Effect of sintering temperature on the accuracy of MIM small-module gears
LIU Zuoshi
MING Aoyang
REN Jihua
WANG Xiaoyi
ZHONG Zhicheng
ZHU Minfeng
ZHU Weidong
Abstract：[Objective]In order to improve the accuracy of small-module gears,small-module gears are prepared by using 420 stainless steel powder as raw material and metal powder injection molding(MIM)process at a sintering temperature of 1 330-1 360℃.The injection blank with the best micro-morphology was taken as a prerequisite to study the effect of sintering temperature on the accuracy of small-module gears.[Methods]MLA650F field emission scanning electron microscope was used to observe the microscopic morphology of the gear injection blanks;JE 20 gear measuring center,Image J software,and Rockwell hardness tester were used to measure the accuracy,porosity,and hardness of the sintered gears,respectively.[Results]The results show that under 110 MPa injection pressure,when the sintering temperature is increased from 1 330℃to 1 350℃,the porosity of the gear surface decreases by 48.28%,the density increases by 5%,the hardness increases by 8.22%,the shrinkage continues to increase,and the accuracy is gradually improved;when the temperature is more than 1 350℃,the porosity decreases by 20%,the density decreases by 0.26%,the hardness decreases by 0.51%,the shrinkage rate increases slowly,and the accuracy of the gear gradually decreases;when the sintering temperature is 1 350℃,the gear has the best comprehensive performance,with a porosity of 1.5%,a density of 7.56 g/cm3,a hardness of 39.5 HRC,a shrinkage rate of 14.1%,and the highest accuracy level of grade 7 in the GB/T 2363-1990 testing standard.
Keywords：Metal powder injection moldingDimensional accuracySintering temperatureShrinkage ratePorosityDensityHardness
Publication Date：2025-09-15
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：7( 136-142 )