PSI - Issue 59

Kozulin S. et al. / Procedia Structural Integrity 59 (2024) 391–398 S. Kozulin et al. / Structural Integrity Procedia 00 (2019) 000 – 000

393

3

2. Material and Research Methodology

The methodology of the research included the following statements. Most of the supporting bands for rotating kilns are manufactured from medium-carbon steels 35L, 25MnSiL, 30MnSiL, and 34L-ESH (Table 1 (Spec. 22-170-87)). The mechanical properties of the steels are provided in Table 2.

Table 1. Chemical composition of steels for manufacturing bands.

Chemical composition, wt. % G О S Т 26291 -87

Material

C

Si

Mn

S

F

Cr

Ni

Cu

35L

0.32-0.40 0.22-0.28 0.25-0.35 0.30-0.37

0.20-0.52 0.60-0.81 0.60-0.80 0.20-0.52

0.45-0.90 1.00-1.30 1.10-1.40 0.40-0.90

0.045

0.040

-

-

-

25MnSiL 30MnSiL 34L-ESH

≤0. 030 ≤0. 040 ≤0. 020

≤0. 030 ≤0. 040 ≤0. 030

≤0. 30

≤0. 30

≤0. 30

-

-

-

≤0. 30

≤0. 03

≤0. 30

Table 2. Mechanical properties of steels for manufacturing bands.

Mechanical properties

Material

H ardness, НВ

KCU, j/cm 2

Ϭ т , MPa

Ϭ в , MPa

δ, %

Ψ, %

35L

275

491

15

25

34

137-166

25MnSiL

245

470

18

30

29

123-149

30MnSiL 34L-ESH

343 296

589 519

14 23

25 30

29 37

≥156

152-170

Experimental research was conducted by welding full-scale specimens with thicknesses of 480 and 620 mm from 35L and 34L-ESH steels. The calculation of the expected chemical composition of the weld metal was performed according to the methodology presented in Syshchuk-Slusarenko et al. (1981). MESW CN was carried out using fluxes AN-8U and AN-9. The electrode wires were fed into the welding zone using welding machines A-645, A 1304, and ASH113M2 and power sources TShS 3000-3 and PSM-1000. The analysis of the microstructure of welded joints was performed using the MIM 7 microscope. The macro hardness of characteristic areas of welded joints was determined using the portable dynamic hardness tester TEMP 2. Quality control of welded joints was performed using the UD4-T device. During the development of the technology for repairing through cracks in MESHW, the following methods were employed. The selection of edge preparation parameters was carried out in accordance with the methodology as shown in the work of Kozulin (2011). The development of techniques to enhance the technological strength of welded joints and methods to minimize residual deformations of welded joints was conducted in accordance with the methodologies described in Kozulin et al. (2010, 2011), Prohorov (1962). The assessment of the influence of the thermal cycle of MESHW on the structure and mechanical properties of welded joints was performed according to the methodology described in the work of Kozulin et al. (2022). The correction of through cracks in the bands of rotating cement kilns using MESW CN was carried out using the routing technology presented in the work of Kozulin et.al. (2021). Based on the results of the conducted research, a detailed scheme for organizing workplaces for repairing through cracks in the bands of rotating kilns in their place of operation has been developed (Fig. 2).