PSI - Issue 30

Nikolay I. Golikov et al. / Procedia Structural Integrity 30 (2020) 93–99 Author name / Structural Integrity Procedia 00 (2020) 000–000

95

3

Table 1. Chemical composition in % and mechanical properties of 09Mn2Si steel according to GOST 19281-2014.

Impact strength (U-notch) (J/cm 2 )

Tensile strength (MPa)

Elongation (%)

С

Si

Mn

Ni

S

P

Cr

V

N

Cu

As

0,5

1,3

≥ 34 at - 70° С

<0,12

<0,3 <0,035 <0,03

<0,3

<0,12

<0,008 <0,3 <0.08

≥ 490

≥ 21

0,8

1,7

Table 2. Chemical composition of St3sp steel in % according to GOST 380-2005. C Si Mn Cr Ni P

S

Cu

Al

Fe

0.14-0.22

0.15-0.30

0.40-0.65

≤ 0,30

≤ 0,30

≤ 0,04

≤ 0,05

≤ 0,30

-

Bal

Table 3. Chemical composition in % and mechanical properties of electrodes.

Impact strength (V-notch) (J/cm 2 )

Tensile strength (MPa)

Elongation (%)

Electrode grade

С , %

Si, %

Mn, %

Ni, %

Mo, %

S, %

P, %

UONI-13/Moroz

0,075

0,3

0,7

2,8

-

0,010

0,017

210

660

22,0

≥ 49 at -30° С

540

29

LB-52TRU

0,09

0,42

0,9

-

-

0,017

0,020

Bevel edges with a scarf angle of (25 ± 2)°, a roof face of 2 mm and a weld gap of 1.6 mm for arc welding of a butt joint according to GOST 5264-80 were applied on 09Mn2Si steel plates with dimensions of 200x300x12 mm and St3sp steel plate of 300x500x7.5 mm in size. Structural elements, their size, and symbols are given in Table 4.

Table 4. Structural elements and their dimensions (GOST 5264-80).

g

e

Structural component

S

=

Weld symbol

Assumed deviation.

of prepared edges of the welded parts

Assumed deviation.

S 1

of welded joint

Nom.

Nom.

+1,5 -0,5 +1,5 -0,5

0,5

7,5

12

±2

S17

0,5

12

19

±2

Single welding of 09Mn2Si steel plates was accomplished in three passes with LB-52TRU and UONI 13/Moroz electrodes with the following diameters: 3.0 mm for the root pass and 4.0 mm for the fill and cap passes (Fig. 1, b). The following welding modes were selected and performed for the investigation: DC welding (DCW) and current modulation with a welding frequency of 1.67 Hz (WCM-1.67) and 5 Hz (WCM-5) — a method for adaptive pulse arc welding. The plates were welded at natural low climatic temperatures (-45 °C). DC welding was performed at room temperature as well to compare the results of studies. Single welding of St3sp steel plates was accomplished in two passes at negative (-40 ° С ) and positive (+20 ° С ) ambient temperatures using LB-52TRU locally produced electrodes with complete cooling of the root pass. DC welding and welding current modulation were performed at a pulse recurrence rate of 1.67 Hz (WCM-1.67). The following inverter welding power sources were used for welding: FEB-315 MAGMA for adaptive-pulse welding and NEON VD-315 for direct current welding. Tables 5 and 6 presents welding modes and parameters of the samples.