摘要
通过对扭矩不合格自攻螺钉低倍组织和断口形貌的检验分析,总结了SWRCH22A自攻螺钉加工过程中导致扭矩不合格的原因。认为热轧盘条残余缩孔、奥氏体混晶组织以及球化退火、渗碳淬火热处理工艺不当降低了自攻螺钉扭矩,影响其使用性能。针对性提出了热轧盘条生产过程中连铸头尾坯及冶炼深脱氧关键工艺的控制要求和自攻螺钉加工过程中无检验手段调整热处理工艺的判断方法等措施。采取措施后,热轧盘条的致密度和均匀性满足加工要求,自攻螺钉获得硬度梯度良好的浅层渗碳淬火组织,扭矩合格。
Through inspection and analysis of microstructure and fracture morphology of self tapping screws with unqualified torque,the reasons for unqualified torque during processing of SWRCH22A self tapping screws were summarized.It is be-lieved that residual shrinkage cavity,mixed austenite crystal structure,and improper spheroidizing annealing,carburizing and quenching heat treatment processes of hot rolled wire rods have reduced torque of self tapping screws and affected their performance in use.Targeted measures have been proposed to control the key processes of continuous casting head and tail billets and smelting deep deoxidation in production process of hot rolled wire rods,as well as judgement method for adjus-ting heat treatment process without inspection methods during self tapping screw processing.After taking measures,density and uniformity of hot rolled wire rod meet processing requirements,and self tapping screw obtains shallow carburized and quenched structure with good hardness gradient,and torque is qualified.
作者
温国栋
Wen Guodong(Rockcheck Steel Group Co.,Ltd.,Tianjin 300352,China)
出处
《金属制品》
CAS
2023年第5期38-40,46,共4页
Metal Products
关键词
SWRCH22A
自攻螺钉
扭矩
混晶组织
球化退火
SWRCH22A
self tapping screw
torque
mixed crystal structure
spheroidizing anneal
