球化退火后的深冷处理对9SiCr钢强韧性的影响  

Influence of Deep Cryogenic Treatment on Strength and Toughness of 9SiCr Steel after Spheroidizing Annealing

作　　者：曹衡 王宇 徐军航 温秋林 高云保 赵岭 娄延春 CAO Heng;WANG Yu;XU Jun-hang;WEN Qiu-lin;GAO Yun-bao;ZHAO Ling;LOU Yan-chun(National Key Laboratory of Advanced Casting Technologies,Shenyang 110022,China)

机构地区：[1]高端装备铸造技术全国重点实验室,沈阳110022

出　　处：《精密成形工程》2023年第12期165-172,共8页Journal of Netshape Forming Engineering

基　　金：辽宁省“兴辽英才计划”(XLYC2008036)。

摘　　要：目的针对9SiCr钢加热脱碳倾向大、加工性较差的问题,研究能够提高9SiCr钢的强韧度与耐磨性的热处理工艺。方法设计一种球化退火后进行深冷处理的新热处理工艺路线来实现对9SiCr钢强度与耐磨性的改良。对比9SiCr钢的等温球化退火与循环球化退火后的组织与性能,确定最适合的球化退火工艺;对退火后的9SiCr钢进行淬火,之后按照淬火后是否进行深冷处理、深冷处理前是否进行预回火进行分组对照试验。结果对于热轧态9SiCr钢,800~750℃往复循环球化退火的强化效果优于各温度下等温球化退火的强化效果;深冷处理12h后,9SiCr钢循环退火组织中的马氏体基体析出了大量超微细碳化物,增强了9SiCr钢的耐磨性与刚性。并且,进行深冷处理前在160℃(9SiCr钢Ms点附近)下保温1h可以增大碳化物的形核率,之后再进行深冷工艺,可以进一步促进碳化物析出,有利于改善9SiCr钢的退火组织,增强材料强度与韧性。结论循环球化退火后预回火并进行深冷处理可以显著提高9SiCr钢的强韧性与耐磨性。The work aim to study the heat treatment process that can improve the strength,toughness and wear resistance of 9SiCr steel,to deal with the large tendency of decarburization during heating and the poor machinability of 9SiCr steel.A new heat treatment process route of spheroidizing annealing followed by deep cryogenic treatment was designed to improve the strength and wear resistance of 9SiCr steel.Firstly,the microstructure and properties of 9SiCr steel after isothermal spheroidizi-ng annealing and cyclic spheroidizing annealing under different parameters were compared to determine the most suitable spheroidizing annealing process.Then,the 9SiCr steel after annealing was quenched,and then divided into groups for contras-tive experiments according to whether deep cryogenic treatment was carried out after quenching and whether pre-tempering was carried out before deep cryogenic treatment.For hot-rolled 9SiCr steel,the strengthening effect of cyclic spheroidizing anneal-ing between 800℃and 750℃was better than that of isothermal spheroidizing annealing at each temperature;deep cryogenic treatment for 12 hours made a large amount of ultra-fine carbides precipitate from martensite matrix in the cyclic annealed structure of 9SiCr steel,which increased the wear resistance and rigidity of 9SiCr steel.Moreover,preheating at 160℃(near point Ms of 9SiCr steel)for 1 hour before deep cryogenic treatment could increase the nucleation rate of carbides.After that,deep cryogenic treatment could further promote carbide precipitation,which was beneficial to improve the annealed structure of 9SiCr steel and increase its strength and toughness.Pre-tempering after cyclic spheroidizing annealing followed by deep cryo-genic treatment can significantly improve the strength and toughness as well as wear resistance of 9SiCr steel.

关 键 词：9SICR钢 热处理 球化退火 深冷处理 预回火 

分 类 号：TG156[金属学及工艺—热处理]