大规格SWRCH35K螺帽淬火硬度不达标原因分析  

Cause analysis of quenching hardness dissatisfaction of large size SWRCH35K nut

作　　者：侯兴辉[1] 熊鑫[1] 屈小波[1] 

机构地区：[1]江苏永钢集团有限公司,江苏张家港215628

出　　处：《金属制品》2018年第1期48-52,共5页Metal Products

摘　　要：采用φ26 mm SWRCH35K盘条制作壁厚8 mm的螺帽,螺帽淬火后表面和心部硬度均低于要求。通过化学成分分析、金相检验和端淬试验,确定母材的淬火性能满足螺帽的加工性能要求。给出3种方案的模拟淬火试验,确定螺帽硬度不达标影响因素有淬火温度较低、淬火介质冷却速度较低、退火中产生表面脱碳等。建议螺帽厂家将淬火温度提高至880℃,淬火介质更换为聚酯酸钠水溶液,检修退火设备并修订退火工艺以确保退火过程不脱碳,可以解决螺帽淬火后硬度不达标问题。Diameter 26 mm SWRCH35K wire rod is used to produce 8 mm wall thickness nut, the hardness of nut surface and core after quenching is lower than requirement. Through chemical composition analysis, metallographic examination and end quenching test, the quenching property of base metal is determined to meet the requirement of processing pertormance of nut. The simulated quenching test of 3 schemes were given, it is determined that the influence factors of nut hardness not up to standard are as follows： the quenching temperature is low, the cooling rate of quenching medium is low, surface decarburization occurs during annealing and so on. It is recommended that the nut manufacturer increase the quenching temperature to 880 ℃, the quenching medium is replaced by aqueous sodium acid solution, inspection annealing equipment and revised annealing process to make sure the annealing process is not decarburization, it solves the problem of nut hardness after quenching does not reach the standard.

关 键 词：螺帽 硬度 淬透性 冷却速率 脱碳 

分 类 号：TG356.45[金属学及工艺—金属压力加工]