40CrNiMoA钢上接头失效分析及热处理工艺改进  

Failure analysis and heat treatment process improvement of 40CrNiMoA steel upper joint

作　　者：柳锦红 刘剑 刘树恒 姚明锋 陈杰 Liu Jinghong;Liu Jian;Liu Shuheng;Yao Mingfeng;Chen Jie(CSSC ZhongNan Equipment Company Ltd.,Yichang Hubei 443005,China)

机构地区：[1]中船重工中南装备有限责任公司,湖北宜昌443005

出　　处：《金属热处理》2024年第2期301-306,共6页Heat Treatment of Metals

摘　　要：为解决40CrNiMoA钢上接头断裂问题,经过对工件断口进行化学成分分析、金相分析及力学性能测试,发现变径R半径过小造成应力集中、材料热处理硬度过高、断后伸长率不足是造成断裂的主要原因。通过优化结构设计和热处理工艺改进来降低产品热处理和使用中的断裂风险,结果表明,将工件变径圆角加大到R20;对材料采用淬火中间保温,控制升温速度至淬火加热温度810℃,慢油淬火,且控制升温速度加热至回火温度570℃,慢油冷却以防止回火脆性后,材料力学性能满足产品设计和使用要求。经实际工况中使用测试,在产品寿命周期内未发生断裂事故。In order to solve the fracture problem of the 40CrNiMoA steel upper joint,the main reasons for the fracture are the stress concentration caused by the small radius of variable diameter R,the over high hardness and the insufficient elongation via chemical composition analysis,metallographic analysis and mechanical property test of the workpiece fracture.The risk of crack fracture in heat treatment and use of the product can be reduced by optimizing the structural design and heat treatment processes.The results show that the mechanical properties of the workpiece material can meet the requirements of both product design and use by increasing the diameter rounded corner to R20,adopting intermediate heat preservation,controlling the heating rate to the quenching temperature of 810℃,cooling in slow oil,and subsequently,controlling the heating rate to the tempering temperature of 570℃plus cooling in slow oil to prevent tempering brittleness.After testing in actual working conditions,no fracture accident occurs in the product life cycle.

关 键 词：40CRNIMOA钢 上接头 失效分析 结构设计优化 工艺改进 

分 类 号：TG157.35[金属学及工艺—热处理]