Shi Kefei, Zhao Fei, Liu Yuan, Yin Sheng, Yang Ronggui
College of Materials and Metallurgy, Guizhou University, Guiyang 550025, China.
Key Laboratory for Materials Structure and Strength of Guizhou Province, Guizhou University, Huaxi District, Guiyang 550025, China.
Materials (Basel). 2022 Jun 2;15(11):3970. doi: 10.3390/ma15113970.
To further improve the mechanical properties of H13 steel at room and high temperatures, its precipitates were regulated based on the Thermo-Calc results. Scanning electron microscope (SEM), electron backscattering diffraction (EBSD), transmission electron microscope (TEM), and X-ray diffraction (XRD) Rietveld refinement were used to study the effect of the intercritical annealing on the microstructure and mechanical properties of H13 steel. The results show that the intercritical annealing at 85095 °C increased the VC volume fraction from 2.23 to 3.033.48%. Increasing the VC volume fraction could inhibit the MC precipitation from 10.01 to 6.63~5.72% during tempering. A large amount of VC also promoted the MC precipitation during tempering at higher dislocation densities. The intercortical annealing simultaneously increased the elongation of H13 steel. An excellent combination (room temperature: ultimate tensile strength (UTS) of 898 MPa and total elongation (TEL) of 19.35%, 650 °C: UTS of 439 MPa, and TEL of 27.80%) could be obtained when intercritical annealing is performed at 900 °C. Meanwhile, after aging at 650 °C for 128 h, the room temperature UTS and TEL decreased by only 31 MPa and 0.52%, respectively.
为进一步提高H13钢在室温和高温下的力学性能，基于Thermo-Calc计算结果对其析出相进行调控。采用扫描电子显微镜（SEM）、电子背散射衍射（EBSD）、透射电子显微镜（TEM）和X射线衍射（XRD）Rietveld精修方法研究了临界区退火对H13钢微观组织和力学性能的影响。结果表明，850950°C的临界区退火使VC体积分数从2.23%增加到3.03%3.48%。增加VC体积分数可使回火过程中MC析出量从10.01%抑制至6.63%~5.72%。大量的VC在较高位错密度的回火过程中也促进了MC的析出。临界区退火同时提高了H13钢的伸长率。当在900°C进行临界区退火时，可获得优异的综合性能（室温：抗拉强度（UTS）为898MPa，总伸长率（TEL）为19.35%；650°C：UTS为439MPa，TEL为27.80%）。同时，在650°C时效128h后，室温下的UTS和TEL分别仅下降31MPa和0.52%。
