Open AccessOptimization of perlite steels mechanical properties for car fasteners stamping
Author(s) -
A.N. Kuzmin,
Aleksey Filippov,
Г. В. Пачурин,
D. A. Goncharova
Publication year - 2019
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/695/1/012030
Subject(s) - materials science , stamping , hot stamping , metallurgy , hardening (computing) , case hardening , automotive industry , decarburization , alloy , composite material , hardness , engineering , layer (electronics) , aerospace engineering
The car fasteners made of pearlitic steels by cold stamping method are to meet special requirements for their structural and mechanical characteristics. The hardware is made of hot-rolled steel, which cannot be used straight after the delivery for fasteners manufacturing due to the poor quality of the structure and surface layer. Therefore, calibrated rolled stock gets heat treatment before drawing. In addition, hardware of strength class 8.8 and higher obtained from alloy steels using cold heading machines are subjected to temper hardening, which often leads to surface decarburization, cracking and distortion of finished products, that afflicts labor and energy efficiency, and, thus, the final cost of production. The article suggests a method for 35X and 38XA pearlitic steels stock treatment excluding recrystallization annealing, rod-like items temper hardening, and including isothermal operation to prevent decarburization, risks and distortion. Passing through the die, hardening the surface due to volume strain and thread rolling impart to M8 bolts and studs the mechanical properties corresponding to strength grades 8.8 and 9.8. This study also has practical application, it allows manufacturers to determine the appropriate mode for producing automotive fasteners.