热处理工艺对2Cr12NiMo1W1V叶片钢组织和性能的影响

Effect of heat treatment process on microstructure and property of 2Cr12NiMo1W1V steel for steam blade

为了解决2Cr12NiMo1W1V钢短时持久性能低的问题,采用OIM、SEM、TEM等手段研究了不同淬火和回火工艺下超超临界叶片用2Cr12NiMo1W1V马氏体耐热钢的组织、室温力学性能及短时持久性能。结果表明,随着淬火温度的提升,抗拉强度和冲击吸收功略有增加,屈服强度和硬度呈降低趋势,塑性变形不明显,合金的持久性能显著增加。2Cr12NiMo1W1V优化的热处理工艺为1038℃淬火+675℃回火,合金的强韧性和持久性能较好。微观组织分析表明,提高淬火温度,合金中的大颗粒M23C6的碳化物更多固溶到基体中,并在回火过程中大量析出细小的M23C6相,减少了短时持久过程中裂纹起源,阻碍位错运动,使合金抵抗高温变形的能力增加,改善了合金的持久性能。

In order to solve the problem of low creep fracture time of 2 Cr12 NiMo1 W1 Vsteel,the microstructure,room temperature mechanical properties and short-term creep fracture strength of 2 Cr12 NiMo1 W1 V martensitic heat-resistant steel for ultra-supercritical blades under different quenching and tempering processes were studied by means of OM,SEM and TEM.The results show that the tensile strength and impact absorbing energy increase and the yield strength and hardness decrease with the increase of quenching temperature.The optimized heat treatment process of 2 Cr12 NiMo1 W1 Vis quenching at 1038℃and tempering at 675℃.The strength,toughness and durability of the alloy have good match.The microstructure analysis shows that with the increase of quenching temperature,the carbide of M23 C6 with big size in the alloy is more solid solution in the matrix,and result in a large number of fine M23 C6 phases are precipitated during tempering.Which reduces the crack origin in the short-term creep test process,at the same time,the dislocation movement was hindered.Thus the ability of the alloy resist high-temperature deformation increased,and the creep fracture property of the alloy is improved.