PSI - Issue 14

Santosh Kumar et al. / Procedia Structural Integrity 14 (2019) 872–882 Santosh / Structural Integrity Procedia 00 (2018) 000–000

874

3

Table 1. Chemical composition of H13 steel produced through both routes

Material

C

Si

Mn 0.4 0.45

P

S

Cr

Mo 1.3

V

CR

0.4

1

0.025

0.003 0.001

5

1

SF 1.35 Room temperature tensile test specimens from both route materials, at both hardness ranges were prepared in longitudinal and transverse directions. Specimens were prepared per ASTM E8 Standard. Tensile test was carried out on universal testing machine (ZWICK/ROELL). Three tests were carried out for each set. Average values have been used for analysis. Charpy impact samples were prepared in longitudinal, transverse and short transverse directions. Test specimens were prepared per standard ASTM E23. The testing was done on ZWICK/ROELL make machine (450 J capacity). Three tests were carried out for each set. Average values have been used for analysis. Fracture toughness test specimens were extracted from TS and LS orientations as shown in Fig. 2 Error! Reference source not found. . The specimens were prepared per ASTM E399 Standard. The Fracture toughness (K IC ) test was carried out on Servo Hydraulic MTS machine of capacity 250 kN. The test was conducted according to ASTM E399 standard under load controlled mode. Initially specimens were pre-cracked to 2.4 mm to maintain crack to width (a/W) ratio of 0.5. The pre-cracking frequency = 20Hz and final K = 20 MPa √m was selected during the test. Minimum three samples for each orientation were tested. Average values have been used for analysis. 0.46 0.92 0.01 5.2 1.29

Fig. 2. Fracture toughness sample orientation

Microstructural analysis and fractography was carried out for both route materials. For microstructural analysis, a CARL ZEISS optical microscope with Image Analyser software Z.2m was used. Fractography was performed using SEM of CARL-ZEISS MA EVO18 make, equipped with an X-ray energy dispersion system, operated at 5-20 kV. 3. Results and discussion 3.1 Tensile Test Results Average values of tensile test data for both materials are presented in Fig. 3 – Fig. 6. The yield strength (YS) & ultimate tensile strength (UTS) obtained for higher hardness range in both longitudinal and transverse directions are presented in Fig. 3 and the same for lower hardness are presented in Fig. 5. Percentage elongation (%El) & percentage reduction in area (%RA) for higher hardness range in both the directions are presented in Fig. 4 and the same for lower hardness range are presented in Fig. 6. YS, UTS, % El and %RA for both route materials are similar in respective hardness ranges. The YS and UTS obtained were used for fracture toughness test.