PSI - Issue 22

Xiaoteng Wang et al. / Procedia Structural Integrity 22 (2019) 59–63 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

60

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Since the hybrid plasma arc welding (HPAW) was introduced firstly in 2005, significant attentions are paid to this new welding method. Compared with laser-arc hybrid welding, HPAW shows less cost and higher gap tolerance and better bridging ability. In comparison with GMAW, HPAW provides deeper welding penetration, higher welding speed and less deformation. In this paper, an application of HPAW in welding of AHSS in manufacturing industry is reported. The fatigue life of welding joints with those two methods is investigated. Furthermore, to find out the difference of fatigue life, both optical microscope and electron microscope analysis are carried out.

Nomenclature A

AHSS: advanced high strength steel GMAW: gas metal arc welding HPAW: hybrid plasma arc welding

B C

2. Experimental setup Advanced high strength steel plate Q500D of 12mm thickness is obtained and sectioned to dimension of 800mm×150mm. The chemical compositions of Q500D and ER50-6 welding wire are listed in Table1.

Table1. The chemical compositions of Q500D and ER50-6 welding wire (wt %) Alloy C Si Mn P S Cr Ni

Fe

Q500D

0.11

0.30

1.60

0.02

0.015

0.15

0.2

Bal

ER50-6

0.07666

1.02

1.73

0.011

0.018

0.057

0.012

Bal

Plates were joined by HPAW and GMAW, techniques at the flat position (1G / PA). The main welding parameters are shown in Table2. Due to the large heat input and slow welding speed of GMAW, three passes are needed to fill the groove. As a comparison, the weld gap was filled with only one pass.

Table2. Welding parameters of the welding process of Q500D

I 1 /U 1 (backing weld)

I 2 /U 2 (back sealing weld)

I 3 /U 3 (cosmetic weld)

Preheat temperature

Welding speed

GMAW

150 A/22V

150 A/22V

250 A/27V

300mm·min -1

100~120℃

Plasma current I P

MAG current I M

MAG voltage U M

Preheat temperature

Welding speed

HPAW

270/A

430A

28V

600mm·min -1

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