The Quality Analysis of the SCM435 Cold Forging Steel and Technical Research on Rolling Process
|Keywords||SCM435 Cold Heading Steel Rolling process Hardness|
SCM435 cold heading steel is the main raw material for the production of Advanced fasteners fastener industry . The chemical composition of the products on the rod , the surface quality and the performance of cold heading higher . The SCM435 hot-rolled wire production that often appear cold upsetting surface cracking phenomenon , and the production did not raise the hardness requirements remained after抽测SCM435 cold heading steel hot-rolled wire rod surface hardness (superscript th) -325 . The topics for cold heading steel SCM435 site production , to take appropriate measures to reduce the hardness of the SCM435 cold heading steel hot-rolled wire rod , and practiced and worked out a set of rolling process is suitable for the production line . The main contents and conclusions of the study include the following aspects : ( 1 ) from the SCM435 the CCT curve test results within 1-10 ℃ / s cooling rate will be the formation of bainite , when the cooling rate is less than 1 ° C / s appear ferrite and pearlite , by slow rolling , cold cooling rate as much as possible in the relatively slow cooling of the rollers of the transport line of the insulation cover intrinsic phase change . Therefore, to ensure that the cooling rate of the cooling transport line roller transport line should be to reduce the the SCM435 hardness of key . ( 2 ) stainless steel long products cooling transportation line roller cooling conveyor line 21M insulation cover design , due to the cooling rate is too fast , resulting in the SCM435 hardness value can not achieve the desired level . Through the design and application of the fourth paragraph of the roller conveyor insulation cover , the effect is obvious. (3) The test results show that : the finish rolling temperature and low temperature silking , and wire insulation cover travel speed slow help to reduce the surface hardness . By slow cooling after rolling , as far as possible in the complete phase-change cooling insulation cover internal transport line roller conveyor slower cooling rate . To reduce SCM435 hot cold heading steel wire hardness , spit temperature controlled at 800-850 ℃, and the slow cooling process after silking effect , its hardness from the original down to HB270 HB310 .