PSI - Issue 20

Sivtsev M.N. et al. / Procedia Structural Integrity 20 (2019) 148–153 Sivtsev M.N. et al. / Structural Integrity Procedia 00 (2019) 000 – 000

150

3

The chemical composition of the steel shown in Table 1. metallographic analysis was performed on a microscope EM METAM PB-21. The structure of the base metal (Fig. 5) ferritic-perlitic, banded structure, lamellar pearlite and grain size of 6-7 (on a scale of GOST 5639-82 (2003)).

Table 1. Chemical composition of steel St3sp (GOST 380-88) steel C Si Mn Cr

Ni

P

S

Cu

As

Fe

St3sp

0,14 - 0,22

0,15 - 0,3 0,4 - 0,65 < 0,3

< 0,3

<0,04

<0,05

< 0,3

< 0,08

Bal.

3. Results and discussions Table 2 shows welding modes and values sizes HAZ deposited weld metal at a temperature of + 21 0 C.

Table 2. The welding modes and values sizes HAZ, at a temperature (+ 21 0 C). Type Specimen number pulse duration, sec pause duration, sec

frequency of the pulsed control, Hz

HAZ weld surfaces, mm

0,3

0,25 0,27

1,82 1,49 1,17 1,53

2,5 2,5 2,1 1,8 2,0 2,2

№ 1 № 2 № 3 № 4 № 5 № 6

Option А APW

0,45 0,55

0,3

0,3

0,35 0,38

Option B APW stationary mode

0,45 0,55

1,2

0,4

1,05

-

-

-

4,2

№ 7

Fig. 2. The size distribution of the HAZ at +21 0 C. Specimens 1-6 pulsed mode with different pulse train frequencies, sample 7 - stationary regime (see Table 1 in.).

According to the data obtained can draw the following conclusion. The welding conditions at positive temperatures + 21 0 C use adaptive pulse-arc welding mode reduces the HAZ size than when welding in a stationary mode. The average size of the HAZ during stationary welding mode 2 times greater than when adaptive pulse-arc welding mode in all 6 of the illustrated options. Also, there is a positive trend towards a decrease the size HAZ in adaptive pulse-arc welding mode by increasing of pause duration current (see. Table 2, Option B, and Figure 2).