1 Introduction
2 Experiments
2.1 Materials
Material | C | Si | Mn | Cr | Mo | Ni | Nb |
---|---|---|---|---|---|---|---|
Q345R GB713–2014 [23] | 0.160 ≤ 0.20 | 0.255 ≤ 0.55 | 1.412 1.20–1.60 | 0.014 ≤ 0.30 | < 0.001 ≤ 0.08 | 0.0061 ≤ 0.30 | – – |
SA508-3 ASME code [24] | 0.226 ≤ 0.25 | 0.194 0.15–0.40 | 1.475 1.20–1.50 | 0.956 0.40–1.00 | 0.469 0.45–0.60 | 0.227 ≤ 0.25 | – – |
18MnMoNbR GB713–2014 [23] | 0.140 ≤ 0.21 | 0.264 0.15–0.50 | 1.315 1.20–1.60 | 0.166 ≤ 0.30 | 0.524 0.45–0.55 | 0.160 ≤ 0.30 | 0.036 0.025–0.05 |
S30408 GB12771–2019 [25] | 0.048 < 0.08 | 0.479 ≤ 0.75 | 1.170 ≤ 2.00 | 18.33 18.00–20.00 | 0.049 – | 8.248 8.00–11.00 | 0.0059 – |
2.2 Quasi-Static and Dynamic Tensile Tests
2.3 Spherical Indentation Tests
2.4 Mode I Fracture Tests
2.5 Charpy Impact Tests
3 FE Simulation
3.1 FE Modelling of Mode I Fracture Tests
3.2 FE Modelling of Charpy Impact Tests
3.3 FE Modelling of SITs
4 Calculation Method for Fracture Toughness Based on SITs
4.1 Stress State Analysis
4.1.1 Mode I Fracture Tests
4.1.2 Spherical Indentation Tests
4.2 Damage Mechanism Analysis
4.3 Modified CIE Model
5 Calculation Method of Impact Absorbed Energy Based on SITs
5.1 Stress State Analysis of Impact Test
5.2 Damage Mechanism Analysis
5.3 Correlation between Dynamic and Quasi-Static Fracture Toughness
Material | \({\sigma }_{\mathrm{YD}}\) (MPa) | \({\sigma }_{\mathrm{YS}}\) (MPa) | \({\sigma }_{\mathrm{YD}}\)/\({\sigma }_{\mathrm{Ys}}\) |
---|---|---|---|
SA508-3 | 714 | 560 | 1.275 |
18MnMoNbR | 843.2 | 680 | 1.24 |
S30408 | 362 | 278 | 1.30 |
Q345R | 475 | 373 | 1.273 |
Average value | 1.258 |
5.4 Correlation between Dynamic Fracture Toughness and Impact Absorbed Energy
Material | No. | JIC (N/mm) | JID (N/mm) | KV2i (J) |
---|---|---|---|---|
S30408 | 1 | 118.60 | 269.55 | 21.76 |
2 | 120.10 | 272.95 | 22.05 | |
SA508-3 | 1 | 146.07 | 331.98 | 16.19 |
2 | 130.39 | 296.34 | 18.26 | |
Q345R | 1 | 175.97 | 399.93 | 11.64 |
2 | 168.00 | 381.82 | 13.10 | |
18MnMoNbR | 1 | 231.00 | 525.00 | 17.46 |
2 | 250.27 | 568.80 | 17.82 |
6 Results and Discussion
6.1 Fracture Toughness by Modified CIE Model
Material | ET (GPa) | EPO (GPa) | \(\frac{{E_{{{\text{PO}}}} - E_{{\text{T}}} }}{{E_{{\text{T}}} }}\) (%) | Eeff (GPa) | \(\frac{{E_{{{\text{eff}}}} - E_{{\text{T}}} }}{{E_{{\text{T}}} }}\) (%) |
---|---|---|---|---|---|
Q345R | 190 | 118 | –37.9 | 180 | –5.2 |
SA508-3 | 206 | 144 | –30.1 | 199 | –3.4 |
18Mn | 195 | 132 | –32.3 | 200 | 2.6 |
S30408 | 173 | 127 | 26.5 | 182 | 5.2 |
Material | No. | Mode I fracture test | Previous CIE model | Modified CIE model | ||||
---|---|---|---|---|---|---|---|---|
KICT (MPa∙m0.5) | hc (mm) | KICP (MPa∙m0.5) | \(\frac{{K_{{{\text{ICP}}}} - K_{{{\text{ICT}}}} }}{{K_{{{\text{ICT}}}} }}\) (%) | hc (mm) | KICM (MPa∙m0.5) | \(\frac{{K_{{{\text{ICM}}}} - K_{{{\text{ICT}}}} }}{{K_{{{\text{ICT}}}} }}\)(%) | ||
S30408 | 1 | 152.33 | 0.097 | 183.41 | 20.40 | 0.063 | 144.27 | 5.29 |
2 | 0.151 | 231.27 | 51.82 | 0.064 | 147.80 | – 2.97 | ||
SA508-3 | 1 | 171.13 | 0.098 | 231.14 | 35.07 | 0.057 | 175.9 | 2.78 |
2 | 0.101 | 235.45 | 37.58 | 0.051 | 165.18 | − 3.47 | ||
Q345R | 1 | 176.70 | 0. 202 | 248.73 | 40.76 | 0.091 | 165.7 | − 6.23 |
2 | 0. 207 | 261.87 | 48.20 | 0.095 | 167.7 | − 5.09 | ||
18MnMoNbR | 1 | 223.00 | 0.158 | 296.32 | 32.87 | 0.071 | 192.78 | − 13.55 |
2 | 0.178 | 317.52 | 42.38 | 0.064 | 184.37 | − 17.32 |
6.2 Impact Absorbed Energy by Modified CIE Model
Material | No. | KV2i (J) | KV2 (J) | KV2i /KV2( ηi ) (%) |
---|---|---|---|---|
S30408 | 1 | 21.75757 | 307 | 7.09 |
2 | 22.05407 | 314 | 7.02 | |
SA508-3 | 1 | 16.18597 | 193 | 8.34 |
2 | 18.26295 | 184.5 | 9.90 | |
Q345R | 1 | 11.63808 | 193 | 6.03 |
2 | 13.09879 | 191 | 6.86 | |
18MnMoNbR | 1 | 17.4609 | 237 | 7.37 |
2 | 17.82138 | 227 | 7.85 |
Material | No. | KV2 (J) | JID (N/mm) | KV2i (J) | (η = ηi ) | (η = 9.9%) | ||
---|---|---|---|---|---|---|---|---|
KV2S (J) | \(\frac{{KV_{{{\text{2S}}}} - KV_{{2}} }}{{KV_{{2}} }}\)(%) | KV2S (J) | \(\frac{{KV_{{{\text{2S}}}} - KV_{{2}} }}{{KV_{{2}} }}\)(%) | |||||
S30408 | 1 | 307 | 260.48 | 22.72 | 320.62 | 4.44 | 231.87 | − 24.47 |
2 | 314 | 248.18 | 24.31 | 346.21 | 10.26 | 248.13 | − 20.98 | |
SA508-3 | 1 | 193 | 310.64 | 17.35 | 206.89 | 7.20 | 177.05 | − 8.266 |
2 | 184.5 | 273.94 | 21.10 | 213.19 | 15.55 | 215.34 | 16.71 | |
Q345R | 1 | 193 | 344.34 | 14.76 | 244.75 | 26.81 | 150.60 | − 21.97 |
2 | 191 | 336.18 | 15.31 | 223.29 | 16.89 | 156.24 | − 18.20 | |
18MnMoNbR | 1 | 237 | 386.26 | 12.68 | 172.06 | − 27.40 | 129.35 | − 45.42 |
2 | 227 | 353.29 | 14.21 | 180.98 | − 20.27 | 144.98 | − 36.13 |