PSI - Issue 36

V. Kharchenko et al. / Procedia Structural Integrity 36 (2022) 277–283 A.V. Sereda et al. / Structural Integrity Procedia 00 (2021) 000 – 000

282

6

Direction ОY 20GR Direction ОX Direction ОY 28GRA Direction ОX Direction ОY

543

1308

1718

423 428

1175 1180

1413 1414

523 498

1387.3

1849.3

1339

1833

Fig. 4. Dependencies of strength limit R m obtained from uniaxial tensile testing (abscise axis) on the strength limits determined via calculation using ind m R ( □, Δ, ○, ◊ ) and Brinell hardness tests using ind m R (■, ▲, ●, ♦ ) (ordinate axis): ◊ , ♦ – 28GKhNMP; □, ■ – 20HR; Δ, ▲ – 30Kh2SN2MFA; ○, ● – 28GRA.

Fig. 5. Dependencies of values R p0.2 obtained for uniaxial tension testing (abscise axis) on the yield values determined via calculation by 0,2 ind p R ( □, Δ, ○, ◊ ) and Brinell hardness tests 0,2 HBW p R (■, ▲, ●, ♦ ) (ordinate axis). ◊ , ♦ – 28GKhNMP; □, ■ – 20GR; Δ, ▲ – 30Kh2SN2MFA; ○, ● – 28GRA . As seen from Figures 4 and 5 deviations of the determined strength characteristics 0,2 ind p R and HBW m R do not exceed 10% for high-strength steels from the results of hardness data in Table 2 by procedure as compared with R p0.2 and R m . The exceptions are the results of assessment of the strength limit for steel 28GR. The deviations of the strength limits determined from the Brinell hardness tests from those obtained in tension are 10.4 %. Moreover, the deviations in values 0,2 ind p R and ind m R were not higher than 5.2 % obtained via instrumented indentation from those obtained in tension. Noteworthy is that the determination of the strength limit of high-strength steels requires the use of correlation dependence Rm = 0.34 HBW. As a result, the deviations of the calculation results for strength characteristic will not exceed 8% as compared with that one obtained in tension. Therefore, the procedures for the determination of the mechanical metal characteristics from the results of instrumented indentation were analyzed. It is implied that the given procedure can be successfully used for the control of the current state of the material in special-purpose structures both at the stage of incoming inspection and operation.