31CrMoV9钢的离子渗氮

Ion Nitriding of 31CrMoV9 Steel

对φ55 mm 31CrMoV9钢棒材进行了910℃正火、900℃油淬和600℃回火的预备热处理。然后将该棒材加工成10 mm×10 mm×25 mm的试样。将试样在510℃分别进行离子渗氮25 h和45 h。采用金相分析和硬度试验测定了渗层的深度、表面硬度和显微组织,目的是研究31CrMoV9钢离子渗氮的可行性。结果表明,随着离子渗氮时间的延长,深层深度增大,表面硬度升高,但脉状组织趋于严重。此外,渗层无脆性,心部组织良好。结果表明,31CrMoV9钢的离子渗氮表面硬化是可行的。

31CrMoV9 steel bar stock 55 mm in diameter was preliminary normalized by heating at 910℃ and air cooling, quenched from 900℃ in oil and then tempered at 600℃. Subsequently, the bar stock was machined into specimens 10 mm by 10 mm by 25 mm. The specimens were ion nitrided at 510℃ for 25 h and 45 h respectively. After this the specimens were subjected to case depth and surface hardness measurements and to microstructure surveying by using both metallographic examination and hardness test for the purpose of discovering whether surface hardening of the 31CrMoV9 steel by ion nitriding is feasible. The results show that as duration of ion nitiding increase so too do both the case depth and surface hardness, but the vein structure becomes more severe. In addition, the specimens exhibit no brittleness and good core structure. From these results it will be seen that surface hardening of the 31CrMoV9 steel by ion nitriding is feasible.