PSI- Issue 9

Tareq Rahman Mahmood et al. / Procedia Structural Integrity 9 (2018) 71–85 Tareq rahman mahmood , et al./ Structural Integrity Procedia 00 (2018) 000–000

73

3

standard for thin sub size specimens (ASTM Int. 2009), see Fig. 1. The tensile tests were performed using tensile testing machine type (WDW-100 Laryee tensile machine) with a maximum capacity of 100 KN. The machine is a computer controlled electronic universal testing machine provides several functions such as strain rate control, and profiles of load-extension and stress-strain over 70000 points on each profile. Spot welding machine used in the work was (SIP column spot welders machine) type PPV 50 with maximum power of 90 KVA. Machine was provided with electronic timer from 0.04-3.96 second. The current can be adjusted between 200- 11000 Amps. Cone electrode was made from beryllium copper alloy with diameter 13 mm and 45 ◦ angle. The electrode tip diameter is 6 mm.

Table 1. Chemical compositions of low carbon steel and HSLA alloy sheets.

Compositions %

C% 0.06

Si%

Mn% P%

S%

Cr%

Mo% 0.005

Ni%

Cu%

V%

Fe%

Low carbon steel 0.7 mm Low carbon steel 0.9 mm

0.016

0.25 0.45

0.008 0.019

0.004 0.032

0.016 0.011 0.004 Bal. 0.052 0.036 0.006 Bal.

0.0771

0.15

0.017 0.0985 0.002

HSLA

0.1

0.6

1.889 0.025

0.01

0.225

0.158

0.556 0.25

0.048 Bal.

Table 2. Mechanical properties of low carbon steel and HSLA alloy sheet sheets.

Metals

UTS (MPa)

Yield strength (MPa)

Low carbon steel 0.7 mm Low carbon steel 0.9 mm

256 350 640

150 190 425

HSLA steel 0.8 mm

B

A

Fig. 1. (a) Stress-strain tensile test; (b) tensile specimen.

Standard spot welding specimens for tensile shear test were prepared. It consists samples of a rectangular shape with a length of 100 mm and width of 40 mm. Then, they will be welded with overlap distance of 40 mm in a single spot welding nugget. All the specimens were prepared with angel 0º to the rolling direction. of two-sheet

Fig. 2. Spot welding specimen.