PSI - Issue 42

Tereza Juhászová et al. / Procedia Structural Integrity 42 (2022) 1090–1097 Author name / Structural Integrity Procedia 00 (2019) 000–000

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perpendicularly to rolling direction. Tab. 3 contains results of tensile testing of specimens, which corresponds to stress strain curves in Fig. 3(b).

Table 1. Chemical compositions of AISI 304 for given flat bars according to material lists.

Material Grade PL10–E PL10–A

C (%)

Si (%) 0.31 0.35

Mn (%) 1.69 1.22

P (%)

S (%)

Cr (%)

Ni (%) 8.05 8.03

Mo (%) 0.49 0.62

Ti (%)

Cu (%) 0.47 0.69

Co (%)

N (%)

Al (%)

0.019 0.018

0.035 0.036

0.024 0.027

18.31 18.22

0.003 0.001

0.196 0.090 0.006

0.150 0.082 -

Table 2. Declared mechanical properties of AISI 304 by producers at 25°C.

Material Grade

R m [MPa]

R p = 0.2 % [MPa]

R p = 1 % [MPa]

A g [%]

PL10–E

601 654

285 321

302 361

51 47

PL10–A

Table 3. AISI 304 properties measured from tensile test together with standard deviations. AISI 304 R m [MPa] R p = 0.2% [MPa] A g [%] PL10–E 740.0  2.71 353.68  6.84 47.03  0.65 PL10–A 707.4  1.80 473.0  5.68 34.17  0.64

(a) (b) Fig. 1 Material structure at longitudinal and cross-section of PL_10E_02 sample - ( a) and - (b) comparison of tensile tests diagram for plate 10 mm× 50 mm from AISI 304 by A and E producers. 3. Theoretical background Generally, SIF is the most used parameter in fracture mechanics, as a variable describing the stress field in the vicinity of the crack. It can be calculated using opening stress in the crack tip as: � = √ , (1) where a is the crack length, σ is the opening stress and is the shape function dependant on the geometry of the specimen and relative crack length a/W, Irwin (1957), Murakami et al. (1987), ASTM (1991), Tada et al. (2000),