摘要
对Cr5M钢进行热处理实验,分析Cr5M钢回火脆性与硬度的关系及其组织结构对回火脆性的影响;据此提出满足辊面硬度要求的Cr5M钢支撑辊整体浸入式调质处理工艺,探究Cr5M钢支撑辊的整体浸入式调质处理效果。结果表明:Cr5M钢具有一定程度的回火脆性,回火脆性温度范围为300~500℃,400℃回火时Cr5M钢冲击吸收能量达到最低值(7.6 J);250℃附近回火,Cr5M淬火钢中的残余奥氏体(Ar)开始发生分解,分解结束温度约400℃,软韧相Ar的分解是导致回火脆性发生的主要因素;960℃淬火+615℃回火的整体浸入式调质处理可替代支撑辊的差温热处理或表面淬、回火热处理,经整体浸入式调质处理的Cr5M支撑辊的综合力学性能优良,表面硬度均匀,最大与最小肖氏硬度差值仅0.7 HSD,平均肖氏硬度为40.1 HSD,支撑辊工作层(淬硬层)深大于15 cm,工作层组织为回火索氏体+少量的铁素体,工作层硬度仅2.1 HSD。
The heat treatment experiment was conducted on Cr5M steel to investigate the relationship between temper brittleness and hardness and the effect of microstructure on temper brittleness.Based on these investigations,an overall immersion treatment process meeting the hardness requirement of Cr5M back-up roll was proposed,and the overall immersion quenching and tempering treatment effect of Cr5M steel support rollers was explored.It is found that Cr5M steel exhibits a certain degree of temper brittleness characteristics at the temper temperature range of 300–500℃.The lowest impact absorbed energy is ascertained to be 7.6 J for the sample tempered at 400℃.The retained austenite(Ar)in the quenched Cr5M steel begins to decompose at the temper temperature of about 250℃,and the decomposition end temperature is confirmed to be about 400℃.The decomposition of soft phase Ar plays a key role on the temper brittleness of Cr5M steel.The overall immersion treatment(quenching at 960℃and tempering at 615℃)can replace the differential heat treatment or surface quenching and tempering treatment.The excellent comprehensive properties are obtained for the overall immersion quenched and tempered Cr5M back-up roll.The uniform surface hardness is achieved for the roll,the value of maximum and minimum Shore hardness(HSD)difference is only 0.7 HSD,and the average hardness is 40.1 HSD.The working ling(quenching layer)depth of the roll is more than 15 cm.The microstructure of working ling is consisted of tempered sorbite and a small amount of ferrite,and its hardness drop is only 2.1 HSD.
作者
李奇
赵士光
王成
高安阳
斯庭智
LI Qi;ZHAO Shiguang;WANG Cheng;GAO Anyang;SI Tingzhi(School of Materials Science&Engineering,Anhui University of Technology,Maanshan 243032,China;Technology Center,Ma Steel Heavy Machinery Manufacturing Company of Anhui,Maanshan 243000,China)
出处
《安徽工业大学学报（自然科学版）》
CAS
2024年第1期18-24,共7页
Journal of Anhui University of Technology（Natural Science）
基金
安徽省科技重大专项(202103a05020036)。
关键词
Cr5M支撑辊
回火脆性
二次硬化
显微组织
淬硬层
Cr5M back-up roll
temper brittleness
secondary hardening
microstructure
quenching layer
