PSI - Issue 23

Barbara Nasiłowska et al. / Procedia Structural Integrity 23 (2019) 577– 582 Nasiłowska B. / Structural Integrity Procedia 00 (2019) 000 – 000

579

3

550

σ an [MPa]

MR (PM)

L-nk (L) (sp L) L-k

500

450

400

TIG-nk (T)

TIG-k (sp-T)

350

10 4

10 5

10 6

log N f

połączenia wykonane wiązką lasera - niekulowane (L - nk) połączenia wykonane laserowo - kulowane (L - k) joints made with a laser be m – on-shot p ened (L) joints made with a l r beam – shot peened (sp-L)

połączenia wykonane metodą TIG -niekulowane (TIG - nk) połączenia wykonane metodą TIG - kulowane (TIG - k) j ints m de with TIG method – non-shot peened (T) joints m de with TIG method – shot p ened (sp-T) 1.4539 parent material (PM) materiał rodzimy 1.4539 (MR)

Fig. 1. Fatigue life of parent material, joints welded with laser and TIG methods

In the welded joints (non-shot peened) made with TIG method (Fig. 2 c) and a laser beam (Fig. 2 a), the fracture development was multifocal and occurred from the specimen surface transiting into a fatigue zone and then into residual one. The foci of the shot peened specimens detected using analysis of fatigue fracture microfactography were dependent on the resultant nominal stress of the cycle and on the residual stress, and were located up to 200 μ m under the surface (Fig. 2 b, d).

b

a

2 0 µm

100 µm

d

c

2 0 µm

100 µm

Fig. 2. (a, c) foci of fractures in non-shot peened joints and (b, d) shot peened (a, b) made with a laser beam and (c, d) TIG method