PSI - Issue 30

Volume 30 • 2020

ISSN 2452-3216

ELSEVIER

I X E ura s ian Sy mp o s iu m on the p roble ms of s trength and re s ource in lo w cli m atic te mp erature s (EURA S TREN C OL D - 2020 )

Guest Editors: Valeri y V . L e p ov

T heodoros R ousakis Bisong M b elle Samuel

Available online al www.sciencedirect.com ScienceDirect

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Procedia Structural Integrity 30 (2020) 209–215

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Abstract The paper presents the features of various fusion welding and cladding methods using auxiliary cold and hot wires in order to increase productivity and improve the quality of welded joints and deposited layers. The introduction lists the various methods of welding that use an additional wire is heated as well as cold. The section “Theoretical and experimental results” presents a method for calculating heat input into a base metal using a heated filler wire and shows the dependence of heat input on its relative amount. The effect of different amounts of filler wire on the shape and size of the welds is shown. A comparative assessment of the effectiveness of using various schemes for introducing an additional heated filler wire into the weld pool was made. The article discusses the use of standard equipment for welding with an additional inverter source for heating filler wire. The influence of automation of the TIG process with cold and hot wire on the lateral shrinkage of 0.8%C-15%Cr-5%Ni-2%Cu 1%Ti-0.7%Si heat resistant steel was studied. The optimal heating conditions were determined to reduce the concentration of Fe in the third layer of deposited metal in the nodes operating in the underwater production of hydrocarbons. The findings present the results achieved in the course of this study, as well as its theoretical and practical significance. The general patterns of the use of arc-free heating of the wire, including in the extended overhang of the electrode, are revealed. Methods have been developed for calculating the heating modes of additional filler wires of various diameters and chemical compositions. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Keywords: fusion welding; cladding; cold wire; hot wire IX Eurasian Symposium on the problems of strength and resource in low climatic temperatures (EURASTRENCOLD-2020) Advanced welding and cladding methods using auxiliary cold and hot wires Pavel Zhilin*, Gennadiy Gavrilov, Eugene Gerasimov, Oleg Melnichenko Nizhny Novgorod State Technical University, 24, Minin Street, Nizhny Novgorod, 603950, Russia Abstract The paper presents the features of various fusion welding and cladding methods using auxiliary cold and hot wires in order to increase productivity and improve the quality of welde joints and eposited layers. The introduction lists the variou methods of welding that se an d itional wire is heated as well as cold. Th sec ion “Theoretical an experimental results” presents a m thod for calcul ting heat input into a b se metal using a heated filler wire and shows the de ndence of heat in ut o its relative amount. The eff c of different amounts of filler wir on the shape and size of t w lds is shown. A comparative assessment f the effectiveness of using vari s chemes for ntr ducing an additional heated fill r wire into the weld pool was made. The articl discusses the use of standard equip nt for wel ing with n additional inverter source for heating filler wire. The influ nce of automation of th TIG process w th cold and hot wire on the lateral shrinkage of 0.8%C-15%Cr-5%Ni-2%Cu 1%Ti-0.7%Si heat resistan steel was studied. The optimal heati g c nditions wer determined to r duce the concentration of Fe in the third layer of deposited metal in the nodes operating in the underwater production of hy r carbons. The findings present the results achieved in the course of this study, a well s its theoretical and p actical s g ificance. The general patter s of the use of arc-free heating of wire, includ ng in the ext nded overhang of the electrode, are reve led. Methods h ve bee developed f r calculating the heating modes of a ditio al filler wir s f various diameters an chemical compositions. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review u der responsibility of EURASTRE COLD - 2020 guest editors Keywords: fusion welding; cladding; cold wire; hot wire IX Eurasian Symposium on the problems of strength and resource in low climatic temperatures (EURASTRENCOLD-2020) Advanced welding and cladding methods using auxiliary cold and hot wires Pavel Zhilin*, Gennadiy Gavrilov, Eugene Gerasimov, Oleg Melnichenko Nizhny Novgorod State Technical University, 24, Minin Street, Nizhny Novgorod, 603950, Russia

* Corresponding author. Tel.: +7-920-072-69-56. E-mail address: cc.nn@mail.ru * Corresponding author. Tel.: +7-920-072-69-56. E-mail address: cc.nn@mail.ru

2452-3216© 2020 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of the EURASTRENCOLD - 2020 guest editors 2452-3216© 2020 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of the EURASTRENCOLD - 2020 guest editors

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors 10.1016/j.prostr.2020.12.032

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1. Introduction Investigations of the use of auxiliary cold and hot wires have been carried out by Saenger (1971), Saenger (1970), Van Dyke and Wittstock (1972), Konischev et al. (1987), Konischev and Zhilin (1988), Konischev et al. (2015), Zhilin and Gerasimov (2019) in relation to various welding and cladding methods (Figure 1). Laser and electron beams, plasma, submerged, gas tungsten and metal arcs, as well as electroslag and oxyfuel gas have been used as a heat source. As a result, the general patterns of the wire heating by current passing in accordance with the Joule-Lenz law have been revealed, including with an increased electrode extension. In addition, some methodologies have been developed for calculating the heating modes of the auxiliary filler wires (AFW) of various diameters and chemical compositions. Also, requirements have been determined for power sources and separate heating units that can be built into different welding and cladding machines.

Fig. 1. Fusion welding and cladding methods with auxiliary cold and hot wires.

Nomenclature Q

heat input arc voltage

U a

U hw

hot wire voltage

I a

arc current

I hw

hot wire current

the penetration profile coefficient the reinforcement profile coefficient

 pen  rein

Р c Р h H C

the ratio of cold wire the ratio of hot wire penetration depth weld bead height weld bead width

В wbw

the ratio of the base and filling metals

 0

F c.c-s.a. cladding cross-sectional area F p.c-s.a. penetration cross-sectional area F w.b.s-c.a. weld bead cross-sectional area

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2. Theoretical and experimental results

Fig. 2 shows the calculation results of (Q) heat input values [kJ/mm] for hot wire submerged arc cladding in accordance with the following formula: ��� where U a and U hw are arc and hot wire voltage values [V]; I a and I hw are arc and hot wire current values [A]; V is cladding speed [mm/min]. 60 1000 ) ) ( (       v I Q U I U hw hw a a

Fig. 2. Heat input vs the relative amount of heated AFW.

Fig. 3. Schemes of the AFW feeding into the front (a) and back (b) weld pool parts.

The calculation results are given for the filler wire feeding into the front weld pool part (Fig. 3, a). Their analysis enables to conclude that in order to achieve a similar level of productivity, it is necessary to use twin arc cladding with a twofold increase in heat input (over 14 kJ/mm) instead of less than 10% enhance in the presented case. Fig. 4–6 show the results of the experimental studies of the effect of various amounts of filler wire on the profiles of welds and deposited beads. Automatic hot wire submerged arc welding and cladding have significant advantages over the conventional processes. In particular, the deposition rate increases by 1.5…2.0 times while the penetration depth and the ratio of the base and filling metals reduce by 2…3 times. Based on the results of the full factorial experiment, mathematical models have been developed. They include dependences of the weld pool length, relative slag mass, penetration depth, weld bead height, cladding cross-section area, the ratio of the base and filling metals, dimensions of the heat-affected zone (HAZ) depending from the parameters of the welding and cladding processes using AFW. Also, a methodology has been proposed for calculating these parameters and assessing their effect on the basic mechanical properties of the formed wear- and corrosion-resistant coatings and various welded joints such as presented by Konischev et al. (1987), Konischev and Zhilin (1988), Konischev et al. (2015), Zhilin and Gerasimov (2019).

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a)

b)

Fig. 4. The penetration and reinforcement profile coefficients vs the ratio of the cold (a) and hot (b) wires:  pen is the penetration profile coefficient;  rein is the reinforcement profile coefficient; Р h and Р c are the ratio of cold and hot wires.

a)

b)

Fig. 5. Penetration depth, weld bead height and width vs the ratio of the cold (a) and hot (b) wires: H is penetration depth; C is weld bead height; В wbw is weld bead width; Р h and Р c are the ratio of cold and hot wires.

a)

b)

Fig. 6. The ratio of the base metal, cladding and penetration cross-sectional areas vs the ratio of the cold (a) and hot (b) wires:  0 is the ratio of the base and filling metals; F c.c-s.a. is cladding cross-sectional area; F p.c-s.a. is penetration cross-sectional area; F w.b.s-c.a. is weld bead cross-sectional area; Р h and Р c are the ratio of cold and hot wires

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The use of conventional equipment consisting of unified units (a double-head welding tractor or a welding head, a welding head and a semiautomatic machine, a welding tractor and a semiautomatic machine, two semi-automatic machines, a GTAW manual torch with a wire feed channel, an automatic GTAW head with an insulated contact tube, etc.) enable to implement of the welding or surfacing processes with minimal capital costs. Simultaneously with an increase in labor productivity, the number of workers is reduced, the quality of welds is improved due to decreasing the penetration depth and the ratio of the base and filling metals. Deposition with various combinations of surfacing materials having different properties reduces the consumption of electricity and flux, as well as the number of weld beads and filling passes. Also, it decreases HAZ dimensions and heat input into the base metal. In addition, the appearance of the weld beads becomes better, sanitary and hygienic conditions at workplaces are improved. An advanced programmable welding power source enables to control the GTAW process, as well as heating and feeding AFW to the weld pool. Synchronous pulsed welding and heating current modes can be used to improve the weld quality or to facilitate out-of-position welding. The important parameters of the modes are pulse current, wire heating current, wire feed speed, arc length, and vibration parameters. Hot wire GTAW significantly improves deposition performance compared to the cold wire process. While cold wire GTAW enable to form a weld at a speed of about 20 cm/min, welding speed reaches 80…100 cm/min for the automatic hot wire GTAW process. As a result, welding time is reduced, narrower HAZ is formed, filler wires with the base metal mixing and risk of hot cracking are decreased such as presented by Makarov and Yakushin (2014).

Fig. 7. The hot-wire GTAW facility.

Fig. 8. The average transverse shrinkage for different GTAW methods (plates from the 0.8%C-15%Cr-5%Ni-2%Cu-1%Ti-0.7%Si heat resistant steel of different thicknesses).

Fig. 9. The three-layer hot-wire deposition on equipment parts for subsea hydrocarbon production.

Fig. 10. The terminal for presetting of hot-wire parameters.

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a)

b)

Fig. 11. The process of the chemical composition control (a) and iron content (b) in various deposited layers obtained using the ERNiCrMo-3 hot-wire on the AISI 8630 steel.

The prototype of inverter power source for AWF heating has been manufactured in collaboration with the “Technotron” welding equipment factory (Cheboksary, Russia). Also, industrial tests of welded structures have been carried out in relation to the procedures used by “Gazprom” PJSC. The effect of AWF heating on residual stresses has been investigated using two plates from the 0.8%C-15%Cr 5%Ni-2%Cu-1%Ti-0.7%Si heat resistant steel with a size of 200×50 mm and different thicknesses (1.2, 1.5, and 3.5 mm). The plates have been butt-welded without gap by three methods (manual, automatic conventional and hot-wire GTAW) using the facility presented in Fig. 7. The linear dimensions of the plates have been measured before and after welding at four points. Also, angular deformations have been assessed. Transverse shrinkage of the welded joints has been the smallest after the automatic hot-wire GTAW process for all thicknesses studied (Fig. 8). The achieved results are of interest to enterprises in the aircraft industry. The optimal AFW heating modes have been calculated for an automatic hot wire GTAW procedure to manufacture structures from the 0.2%C-0.3%Mn-0.5%Cu-0.5%Ni low alloy and 0.8%C-18%Cr-10%Ni stainless steels used in powder metallurgy in order to reduce the number of discontinuities due to the high hydrogen content in the welds such as presented by Arzamasov et al (2002). Another solved problem is the reduction of iron in the third deposited layer on equipment parts for subsea hydrocarbon production (Fig. 9–11). These achievements can also be applied to improve technologies used by “Gazprom” PJSC. 3. Conclusions Based on the obtained results, the following conclusions were drawn: 1. The calculations of heat input for submerged arc cladding using cold and hot AFW have been done. 2. The optimal modes of heating AFW have been assessed. 3. The effect of various amounts of filler wires on the profiles of the welds and deposited beads has been investigated. 4. The theoretical and practical significance of the performed studies lies in the fact that their main results can be applied in the practical implementation of the methodology for calculating AFW heating modes to develop and produce new types of welding and cladding equipment using an arc, plasma, laser and electron beams a heat source.

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Acknowledgements The work was performed at the NSTU named after R. E. Alekseev under the Agreement with “Ruspolimet” PJSC dated September 20, 2019. No. 19/2504/83-04/1075/19, also co-financed by the Ministry of Science and Higher Education of the Russian Federation under the Agreement dated December 18, 2019. No. 075-11-2019-084 (state contract identifier 0000000007519SZB0002), topic: “Creation of a high-tech production of materials, products and equipment using additive technologies and gas conditioning technologies on the basis of “Ruspolimet” PJSC. References Arzamasov B, Sidorin I, Kosolapov G, 2002. Materials science. Bauman Moscow state technical University, 119-149. (in Russian) Zhilin, P., Gerasimov, E., 2019. Features Of Various Types Of Welding And Surfacing With Heating An Additional Filler Wire. International Conference “Welding in Russia 2019: State-of-the-arts and perspectives”. Tomsk, Russia, 107–108. (in Russian) Konischev, B., Zhilin, P., 1988. Comparative Evaluation of Two Filler Wire Feeding Options for Submerged Arc Welding. Automatic Welding 3, 16–17. (in Russian) Konischev, B., Zhilin, P., Lebedev, S. 2015 Improving Productivity and Quality of the Welding Process in CO 2 Using Auxiliary Cold Wire. Welding and Control 4, 42–46. (in Russian) Konischev, B., Zhilin, P., Shayakov, V., 1987. Automation of Surfacing in the “VTORCHERMET” Company. Welding Production 6, 5–6. (in Russian) Makarov E, Yakushin B, 2014. Theory of weldability of metals and alloys. Bauman Moscow state technical University, 77-79. (in Russian) Saenger, J.F., 1971. Hot Wire – a New Dimension in Arc Welding. Welding and Metal Fabrication 6, 227–234. Saenger, J.F., 1970. Gas Tungsten Arc Hot Wire Welding – a Versatile New Production Tool. Welding Journal 5, 363–371. Van Dyke, L., Wittstock, G., 1972. Submerged Arc Welding and Surfacing with Hot Wire Additions. Welding Journal 5, 317–325.

ScienceDirect Available online at www.sciencedirect.com Sci nceDirect Structural Integrity Procedia 00 (2020) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2020) 000–000 Available online at www.sciencedirect.com

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Procedia Structural Integrity 30 (2020) 167–172

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Abstract The residual stresses in the weld metal and heat affected zone welded by experimental flux-cored wires (FCW) modified by rare earth elements from the Tomtor deposit (Yakutia, Russia) were studied using X-ray diffraction methods. Alloy powders with 10 different concentrations of rare earth elements (REE) were designed and mixed with the filler material of UONI 13/55 covered electrode. The results showed that tensile internal residual stresses occurred in the weld metal and in the heat-affected zone with rare-earth metals. At the same time, compressive internal residual stresses were found in the weld metal and in the welded joint welded by flux-cored wire with 0.7 wt. % total content of REE, which prevent the formation and propagation of post-weld cracks. Microscopy indicated the formation of fine grain weld metal structure with increased hardness. There is a tendency to decrease the width of the heat-affected zone in all samples with REE compared to the heat affected zone (HAZ) width of the samples deposited by covered electrode. An optimal composition of flux-cored wires with a modifying additive with rare-earth metals is proposed. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Keywords: rare-earth elements; flux-cored wires; manual arc welding; microstructure; residual stresses; hardness. 1. Introduction The process of the arc welding is accompanied by high local heating of small areas of the parts to be joined and their relatively rapid cooling. This temperature gradient promotes the formation of internal stresses that arise due to IX Eurasian Symposium on the problems of strength and resource in low climatic temperatures (EURASTRENCOLD-2020) Application of X-ray diffractometry in the study of deposited metal with rare earth elements Stepanova K.V. a, * , Petrov P.P. a , Platonov A.A. a a Larionov Institute of Physical-Technical Problems of the North SB RAS, Yakutsk, 677980, 1Oktyabrskaya St., Russian Federation Abstract The residual stresses in the weld metal and heat affected zone welded by experimental flux-cored wires (FCW) modified by rare earth elements from the Tomtor deposit (Yakuti , Russia) w re studied using X-ray diffracti n methods. Alloy p wd rs with 10 differ nt co centrations of rare earth elements (REE) were designed and mixed with the filler aterial of UONI 13/55 covered electrode. The results sh wed that tensile internal residual str ses occurred in the weld metal and in the heat-affected zone with rare-earth metals. At the same time, compressive internal residual stresses were found in the weld metal and in the welded joint weld d by flux-cored wire with 0.7 wt. % total content of REE, which prevent the formation and propagation of post-weld cracks. Microscopy indicated t e formation of fine grain weld metal structure with increased hardness. There is a tendency to decrease the width of the heat-affected z e in all samples with REE compared to the heat affected zone (HAZ) width of the samples deposited by cover d electro e. An optimal composition of flux-cored wires with a modifying additive with rare-earth metals is propose . © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of t EURASTRENCOLD - 2020 guest editors Keywords: rare-earth elements; flux-cored wires; manual arc welding; microstructure; residual stresses; hardness. 1. Introduction The process of the arc welding is accompanied by high local heating of small areas of the parts to be joined and their relativ ly rapid cooling. This temperature gradient promotes the formation of internal stresse that arise ue to IX Eurasian Symposium on the problems of strength and resource in low climatic temperatures (EURASTRENCOLD-2020) Application of X-ray diffractometry in the study of deposited metal with rare earth elements Stepanova K.V. a, * , Petrov P.P. a , Platonov A.A. a a Larionov Institute of Physical-Technical Problems of the North SB RAS, Yakutsk, 677980, 1Oktyabrskaya St., Russian Federation

* Corresponding author. Tel.: +7-4112-39-0600. E-mail: kseniastepanova@rambler.ru * Corresponding author. Tel.: +7-4112-39-0600. E-mail: kseniastepanova@rambler.ru

2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of the EURASTRENCOLD - 2020 guest editors 2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of the EURASTRENCOLD - 2020 guest editors

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors 10.1016/j.prostr.2020.12.026

K.V. Stepanova et al. / Procedia Structural Integrity 30 (2020) 167–172 Stepanova K.V., , Petrov P.P., Platonov A.A. / Structural Integrity Procedia 00 (2020) 000–000

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unequal expansion and compression of the metal. Internal stresses in the weld arise mainly because of structural phase changes of the metal in the weld and heat-affected zones. Taylor (1961) reported that determination of internal (residual) stresses by X-ray diffractometry methods is based on recording changes in the interplanar spacings of the stressed crystallite. Modern approaches to the study of X-ray diffraction methods are described by Hauk (1997), Welzel (2002, 2005), Genzel (2001). Residual stresses in metals and alloys in certain cases reach the yield strength and even the tensile strength and cause cracking during thermomechanical processing of the material (hardening, grinding, etc.). On the one hand, tensile residual stresses in the surface layers combined with external ones can induce destruction of parts during operation. On the other hand, the occurrence of compressive residual stresses on the surface complicates the formation of cracks and significantly increases the fatigue strength of parts and assemblies of equipment and constructions, as noted by Dudarev (1988) and Ivanova (1986). The interest in methods of weld metal alloying with rare-earth elements is growing now, so the issue of evaluating the residual stresses in a weld and a heat-affected zone with rare-earth metals is very important. Lazko (1981), Efimenko (1980), Cai (2014), Zhang (2007), Li (2017) showed that rare earth elements such as yttrium, cerium, lanthanum, praseodymium, etc. affect on the crystallization process and the formation of the primary weld structure during welding and surfacing of various steels. Therefore, the determination of the mechanisms of the influence of rare earth metals at various concentrations in the weld on the occurrence of internal residual stresses helps to control some properties of the weld metal, such as strength, hardness, impact strength and corrosion resistance. In this research, the residual stresses were studied in the weld metal and HAZ, obtained by deposition with flux cored wires with different contents of rare-earth elements from the Tomtor deposit (Yakutia, Russia) and the optimal composition of flux-cored wires with a modifying additive with rare-earth metals for forming a weld with increased strength properties with reduced stress-strain state was selected. 2. Experimental procedures A commercial grade 09G2S steel plate with a thickness of 12 mm was used as the base metal. Alloy powders with 10 different concentrations of REE (see Table 1) were designed and mixed with the filler material of UONI 13/55 covered electrode. Rare earth material added to the mixture in an amount of 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9; 1% of the total mass of filler wire. Then experimental flux-cored wires (FCW) with diameters of 5 mm, with 15% fill factor were manufactured and weld beads were deposited to steel plates. Manual arc welding experiments were conducted using a VD 306E welding machine at current of 180 A and voltage of 40 V.

Table 1. Chemical composition of experimental flux-cored wires.

Compositions of flux-cored wires

Chemical elements (wt.%) Si Ti V

Mn

Fe

Y

Nb

Pr

Nd

Comp1 Comp2 Comp3 Comp4 Comp5 Comp6 Comp7 Comp8 Comp9 Comp10

9.51 9.21 9.16

2.91

0.009

4.13 4.19 4.03 4.11 4.62 4.15 4.02 4.18 3.85 4.07

2.62 2.78 2.73 2.93 3.58 3.32 3.47 3.66 3.52 3.91

0.0051 0.0087

0.04

0.036 0.057 0.085

0.037 0.067 0.097

3.1

0.01

0.052

2.88

0.013 0.016 0.017 0.022 0.028 0.029 0.031 0.041

0.012 0.014 0.032 0.025 0.033 0.043 0.032

0.0652

9.1

3.3

0.058 0.155 0.117 0.148 0.192 0.129 0.228

0.11 0.18 0.18 0.24 0.25 0.26 0.31

0.14 0.21

-

3.35 3.48

8.83 8.72 8.67 8.53 8.53

0.2

3.2

0.25

3.39 3.07 3.48

0.3

0.31 0.35

0.0538

X-ray diffraction spectra for all samples were detected on a Rigaku Ultima IV X-ray diffractometer with a high precision horizontal goniometer where sample is fixed horizontally. The sample is scanned by an X-ray generator and a sensor, which is a scintillation counter located on the goniometer lever with rotation over a vertical area.

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The diffraction spectrum was recorded in a �  2� scanning scheme with Bragg - Brentano focusing in the range of angles 1230° - 1250° in Co К α radiation (wavelength λ = 0.179020 nm) using a graphite monochromator in the secondary beam. The width of the slit restricting the incident beam horizontally is 10 mm, vertically is 0.50 mm; Seller slits on the incident and diffracted beams - 0.50 mm; the width of the slit restricting the diffracted beam vertically in front of the receiving slit is 0.50 mm. A rectangular beam with a size of (1 x 0.2) mm is focusing on the sample. The operating mode of the X-ray source: U=40 kV; I=40 mA; scanning speed is 0.1 deg/min with 0.01 deg. interval, scan axis: 2 θ / θ . The international diffraction data base PDXL - 2 was used to analyze the diffraction patterns. In order to obtain the profile of the X-ray line corresponding to planes with rear reflection angles, a plane with (hkl) = (220) was chosen. The total width of the diffraction peak at half height was determined (taking into account the standard). Instrumental broadening was detected experimentally by X-ray under the same conditions a reference sample in which the physical broadening is close to zero (D> 0.15 μ m, ρ <10 8 с m -2 ). The standard is made of working samples material by recrystallization treatment. Umanskiy (1982) reported that the residual stresses are characterized by uniform compre ssion or extension (deformation in the elastic zone) of the crystal lattice of metals and alloys and they lead to a uniform change in the interplanar spacings (d) by ∆ d, and therefore to a shift in X-ray interference by an angle ∆θ . Based on this relation, for uniaxial tension, the stress value is determined by the Gorelik (1994) equation (1): where E is Young’s modulus Е = 2.17 * 10 5 MPa, ν is Poisson’s ratio ν = 0.3, d is interplanar distance, ∆ d is the interplanar distance change of the deformed sample, θ 0 is the position of the diffraction line in the absence of deformation, θ is the position of the diffraction line at deformed sample, ∆θ is the shift in the diffraction maximum position of the deformed sample relative to the standard. The microstructure of weld metal was observed by Altami Polar 312 optical microscope. Nitric acid and ethanol in proportion 1 ml HNO 3 per 4 ml C 2 H 5 OH was used for metal etching. The Brinell hardness was determined by MET U1 ultrasonic hardness tester. 3. Results and discussion It has been empirically demonstrated in the surfacing materials, the most vulnerable areas are the weld bead (point 1 in Fig.1) and the lower boundary of the weld (point 2 in Fig. 1).      2 1  0 0 2 * * ctg θ * * ctg * 2   1 * sin   1 sin E d E E d                  (1)

Fig. 1. The schematic picture of the sample with locations of X-ray.

Weld metal obtained by flux-cored wire of Composition 4 has the highest strength properties, hardness is 183 HB, and the minimum segregation sizes at the fusion bo undary reaching 76 μ m are also observed (see Table 2) relative to other compositions. At the same time, the values of residual tensile stresses in the area of the weld bead and in the lower boundary of deposited metal reach 112.4 MPa and 104.4 MPa, respectively, and the level of stress-

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strain state of the deposited material increases. It should be noted that in the deposited metal in all samples, the average elemental content of praseodymium varies from 0.12% to 0.36%, neodymium from 0.03% to 0.23%, cerium from 0.01 to 0. 16%.

Table 2. Some characteristics of deposited metal. Compositions of flux-cored wires REE content in flux (wt.%) Hardness (HB)

HAZ width (mm)

Comp1 Comp2 Comp3 Comp4 Comp5 Comp6 Comp7 Comp8 Comp9 Comp10

0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9

178 173 172 183 180 158 170 167 175 177 163

1,78 2,96 3,14 2,00 2,18 3,04 2,96 2,30 2,70 2,30 3,60

1 0

UONI 13/55

The hardness of the deposited metal of FCW of Composition 7 is 170 HB, which corresponds to the average for all compositions, and the values of residual stresses in weld bead and in the lower boundary of the surfacing are fixed at 68.8 MPa and 47.1 MPa , respectively, as depicted in Fig. 2. Since the results of the X-ray diffraction pattern confirm the predominance of compressive stresses in the sample, we can speak of a reduced level of the stress-strain state at all points of the sample.

Fig. 2. Values of residual stresses σ in samples deposited by different wires and covered electrode UONI 13/55 at 3 points.

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The results of X-ray diffraction analysis in the sample of composition 7 show insignificant distortions of the iron crystal lattice parameter Δ  = 0.00112Å in the weld bead zone and Δ  = –0.00081Å in the lower boundary zone of deposited metal, whereas the value of Δ  = 0.00061 Å in the weld bead zone and Δ  = –0.00038 Å in the lower boundary in the sample, obtained by covered electrode UONI 13/55. The rare-earth metals mainly form finely dispersed refractory compounds as sulfides, silicates, oxides, carbides due to the high thermodynamic activity. A small part of rare-earth metals dissolves in solid solution, forming intermetallic compounds according to the research by Efimenko (2003). The formation in the iron fusion zone of intermetallic compounds with REE in the ferrite grains boundary contributes to its hardening. Moreover, refinement of ferrite grains increases the strength of the metal due to grain-boundary hardening of the polygonized substructure. Thus, REE reduce the diffusion mobility of the weld elements by interacting in electronic level with the elements of the matrix, contributing to a uniform distribution of dislocations with a decrease in their density. The hardening of the weld metal and HAZ is interpreted by the increase in interatomic and intergranular bonds when REE compounds are transferred into the weld pool during manual arc welding. Fig.3 shows the optical microstructure of weld metals, obtained by flux-cored wire of Composition 7 and covered electrode UONI 13/55. Fig 3a presents the non-uniform columnar formations with a width of 98 μ m in the weld zone of flux-cored wire, mixed areas of acicular ferrite are predominate. The fusion zone is characterized by grains with size of 96 μ m (Fig. 3b). The width of the HAZ is 2.96 mm. The average value of the weld metal hardness is 170 HB. Fig.3c,d present the microstructure of weld metal and fusion zone of UONI 13/55. Uniform large columnar formations occurred during cooling of the weld pool; the distance between the ferrite columns is 95 μ m (Fig. 3c). Grains with an average size of 123 μ m formed in the zone of contact of the deposited metal to the base metal (Fig. 3d), perlite areas are edged with ferrite interlayers. The width of the HAZ is 3.60 mm. The average hardness of the weld metal is 163 HB.

a)

b)

c)

d)

Fig. 3. Micrographs of samples deposited by FCW (REE total content is 0.7 wt.%) (a,b) and UONI 13/55 (c,d)

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Thus, in the fusion zone of sample deposited by flux-cored wire with 0.7 wt. % total content of REE, metal is formed with grain sizes 22% less than the grain sizes in the UONI 13/55 metal. There is a tendency to decrease the width of the heat-affected zone in all samples with REE compared to the HAZ width of the samples deposited by covered electrode. 4. Conclusions The results of X-ray diffraction analysis showed that tensile internal residual stresses occurred in the weld metal and in the heat-affected zone with rare-earth metals. At the same time, compressive internal residual stresses were found in the weld metal and in the welded joint welded by flux-cored wire with 0.7 wt. % total content of REE, which prevent the formation and propagation of post-weld cracks. The intermetallic inclusions formed grain boundary at the fusion boundary contribute to the hardening of the polygonized substructure. The composition 7 of flux-cored wire (total content of REE is 0.7 wt.%) was selected as the most optimal in terms of the level of stress-strain state, because a metal with a fine grain structure and an increased hardness value is formed with a reduced stress-strain state. The issue of tensile stresses arising during deposition with REE wires of other compositions requires a more detailed study. Acknowledgements This work was supported by Larionov Institute of Physical and Technical Problems of the North of the Siberian Branch of the Russian Academy of Sciences and funded by Ministry of Science and Education of Russian Federation, Project III.28.1.1 in the frames of Program for Basic Research of the Siberian Branch of Russian Academy of Sciences. References Cai, Y.C. Liu, R.P., Wei, Y.H., Cheng, Z.G., 2014. Influence of Y on microstructures and mechanical properties of high strength steel weld metal, Materials and Design 62, 83-90. Dudarev, E. F., 1988. Microscopic deformation and yield strength of polycrystals. TGU, Tomsk, pp. 256. Efimenko, N.G., 2003. Complex assessment of the effect of yttrium on the properties of welds in steels, Avtomaticheskaya svarka 8, 24-27. Efimenko, N.G., 1980. The use of rare earth metals in coverings of welding electrodes, Svarochnoe proizvodstvo 7, 28-29. Genzel, Ch., 2001. X-ray stress analysis in presence of gradients and texture, Advances in X-ray Analysis 44, 247-256. Gorelik, S.S., Skakov, Y.A., Rastorguev, L.N., 1994. X-ray and electron-optical analysis. MISIS, Moscow, pp.328. Hauk, V., 1997. Structural and residual stress analysis by nondestructive methods: Evaluation .Application. Assessment. Elsevier, Amsterdam, pp. 655. Ivanova, V.S., 1986. Mechanics and Synergetics of Fatigue Failure, Fizika, chimiya i mechanika materialov 22, 62-68. Lazko, V.E., Borisov, M.T., Kovalchuk, V.G., Makarov, E. L., 1981. The effect of cerium on the delayed fracture of a high-strength weld, Avtomaticheskaya svarka 2, 27-29. Li, P. Yang, J.C.., Li, Y., 2017. Welding performance of several new rare earth tungsten electrodes, Materials Science Forum 898, 1117-1122. Taylor, A., 1961. X-ray metallography. John Wiley and sons, New York, London, pp. 993. Umanskiy, Y.S., Skakov, Y.A., Ivanov, A.N., Rastorguev, L.N., 1982. Crystallography, radiography and electron microscopy/ Metallurgy, Moscow, pp.632. Welzel, U., 2002. Diffraction analysis of residual stress. Universitat Stuttgart, Stuttgart, pp.169. Welzel, U., Ligot J., Lamparter, P., 2005. Stress analysis of polycrystalline thin films and surface regions by X-ray diffraction, Journal of Applied Crystallography 38, 1-29. Zhang, Z., Z. Wang, Z., Liang, B., Dong, H.B., Hainsworth, S.V., 2007. Effect of CeO 2 on the microstructure and wear behavior of thermal spray welded NiCrWRE coatings, Wear 262, 562-567.

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Procedia Structural Integrity 30 (2020) 82–86

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Abstract Nowadays, the close interaction between the Russian academic science and industry come true by means of The Digital Economics of Russian Federation State Program. It has pass ahead partially of the Industry 4.0 and 5.0 European programs in case of realization of the analysis of development and control methods of the knowledge-intensive complex engineering systems (CES) that are competitive in the world market of high technologies, products, goods and services for the Arctic and the Subarctic. It has been shown how by the using chaos theory and Bayesian principles on the base of multilevel simulation it could be formulated a general scientific and methodological approach to the problem of identifying, analyzing and choosing alternatives for fundamental research area in order to ensure the disruptive development of manufacturing technologies of the CES production for the long term. The methodology for criterion formation of preference, ranking and multi-criteria selection of the most priority alternatives of the fundamental research for Digital Economics, Industry and Society concepts for the Arctic and the Subarctic has been considered. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Keywords: industrial technologies, fundamental research, complex engineering system; digital economics; Industry 5.0, the Arctic, the Subarctic u IX Eurasian Symposium on the problems of strength and resource in low climatic temperatures (EURASTRENCOLD-2020) A System Approach to Research Development and Creation of the Complex Engineering Systems for Arctic and Subarctic Valeriy V. Lepov a, *, Konstantin D. Panteleev b , Eugeniy G. Rahmilevich b , Eugeniy S. Yrcev b a Larionov Institute of Physical-Techincal Problems of the North SB RAS, 1 Oktyabrskaya Street, Yakutsk, 677980, Russia b FSUE «NPO «Technomash», 40 Maryna Roscha side-street the 3-d Proezd, Moscow, 127018, Russia

* Corresponding author. Tel.: +7-411-239-0601; fax: +7-411-239-0599. E-mail address: lepov@iptpn.ysn.ru

2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of the EURASTRENCOLD – 2020 guest editors

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors 10.1016/j.prostr.2020.12.014

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1. Introduction A “foresight" term was firstly used by Herbert Wells in 1930 as the scientific forecast. At present time it is the system of expertise of strategic sectors of social-economic and innovation development and a discipline use to gather and process information about future operating environment. It could reveal the technological breakthroughs capable to impact of economics and society in a medium and a long-term outlook. Currently for such the scenarios implementation the State development programs used as the “Digital economics of Russian Federation” and other. Particularly the initiative of digital transformation of the economics and society in Europe gain by Germany where from the 2017 was discussed and accepted the program Industry 4.0, as mentioned by Alcácerac (2019), Plakitkin (2018) and other. The strategy choosing means that applying of the general-system approach for economics and industry transformation should base on science and IT-technologies and include the complex engineering systems development. As the requirements hardening to world level for the operational reliability indexes of such systems, and acceleration and expense shortening of product life, so the opportuneness factor of revelation and selection of efficient critical technologies gains particular importance. These technologies provide the priority development of complex engineering systems and operation measures in extreme environment. The process of revealing, analysis and selection of the priority direction of industrial technologies of complex engineering systems development examines as the whole of harmonized system of foresight research, include:  establishment of the enumeration of possible and existing directions of fundamental research for challenging scientific and technological development of the machinery manufacturing;  fundamental basement and probability properties estimation of the revealing direction (states, temps, teams etc.);  formation of the criteria to be used to choice and ranging of most preferential direction.

Nomenclature j

current leap number

coefficient depended of the field of science and technology

K 

NTA CES STR

scientific-and-technological advance complex engineering system scientific and technical revolution

growth rate coefficient

V

volatility of complex multiscale system periods between the technological evolution leaps

y

 t j 

resource capacity coefficient measure of the time scale



2. Methodology and preconditions 2.1. Theoretical preconditions

There two main approaches to scientific and technological development currently exist, - the cumulative model (for step-by-step, evolution development) and leapfrogging model (for scientific revolutions) proposed by Kuhn, 1975. The question about the revolutionary or evolution scenario has been still disputable at present time. 2.2. Informational and Political preconditions The latest developments demonstrate the necessity of range of technologies for monitoring and management of digital information sector of basic science and its applications used the multilevel mathematical models of new type. In the long rang, this will enable to make forecasts for scientific researches and evaluate risks of development. Also

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this will support the management decisions in the field. The creation of tools of analyze, control and manage, of NTA in the field of design and development of CES operated in extreme environment such as Arctic zone thus become a significant task for civil defense purposes. 2.3. Practical preconditions The necessary of higher-level generation of CES and industrial technologies of manufacturing improve the efficiency of the methods for organization the development and implementation for production. At present time in the technology-intensive industries as machinery, the methodology, software and standardization of identification, analysis and selection of priority directions of industry technology of manufacturing of CES are not fully developed. So the set of development in the rocket and space industry had never been realized. 2.4. Methodology of identification, analysis and selection of priority directions of basic research The possibilities and consequences of the emerging and existing areas of scientific and technological progress, which are advisable to study as objects of forecast, should be take into account since they have a significant (and often decisive) impact on the indicators of the appearance of the systems being developed and their components when solving the problems of forecasting the development of CES and industrial technologies for their production. Historically, the process of changing the technical characteristics of CES and industrial technologies for their production, being an integral part of technical progress, is characterized by the alternation of periods of gradual (evolutionary) and revolutionary (breakthrough) development. Areas of gradual development are characterized by a gradual change in characteristics by improving the technologies for the manufacture of CES within the framework of known technological methods and means of technological equipment, and the periods of spasmodic rapid progress of development differ due to critical breakthrough technologies based on methods of new, previously not used or unknown physical principles, technical ideas and solutions. 3. Results and Discussion The abovementioned patterns of development processes greatly complicate the prediction of the technical characteristics of promising CES and industrial technologies for their production, since the process of changing these characteristics cannot be described by a continuous function in general case. Therefore, along with the continuous description at each technological level, a discrete transition to a new one is necessary, thereby the model becomes discrete, structural, multi-level, as have been described by Lepov et al (2016, 2018, 2019). An analysis of the development processes of scientific and technological progress shows that there is a tendency for more frequent leaps, i.e. a decrease in the time intervals between them and an increase in the magnitudes of the jumps themselves. It is necessary to distinguish between leaps of different categories: the most significant are leaps associated with the use of new principles; leaps associated with the implementation of new technologies within the framework of one principle; horse racing associated with the improvement of new technologies. On average, as the analysis shows, the value of the period between jumps is approximated by an exponential dependence of the form: �� � � � ������ � �� , (1) where j is the number of the next jump, τ is the time scale indicator, K τ is a coefficient depending on the branch of science and technology. The question of determining the magnitude of the jump itself is somewhat more complicated. In most cases, the introduction of a new principle or a new solution within the framework of the old one leads to an abrupt increase in one or another characteristic. However, there are cases when, when using the new principle, at first, there is even a deterioration in performance due to the reasons of technological running-in. Also, the dependence should reflect the discrete nature of the jumps. According to the actively developing chaos theory, the rate of change of technology Ω should correspond to the logistic mapping (Verhulst mapping) shown by Gutierrez et al. (2009):