Fasteners are a kind of general parts used for mechanic […]
Fasteners are a kind of general parts used for mechanical connection and fixation. The fastener heat treatment process is divided into two processes, heating and cooling, and the ideal heat treatment quality can be obtained by reasonably controlling the two processes respectively.
(1) Bolts, studs, screws, nuts and special-shaped non-standard parts mainly based on ML35 (32, 40), etc., due to the problem of material hardenability, such parts should be selected with a faster cooling rate during the heat treatment Quenching medium, so as to meet the requirements of hardness, metallographic structure and mechanical properties of parts quenching.
① When the product specification is M4～M16, 3%～5% KR6480 polymer water-falling quenching agent can be selected. If 35, 35A, 35S steel is selected, it can be relaxed to M18～M20.
② When the product specification is M10～M24, 8%～10% KR7280 water-soluble quenching agent can be selected.
③When the product specification is greater than M24, 10%～15% KR7280 hydroquenching agent can be selected.
④ When the product is mainly 45 steel, KR6480 or KR7280 can be selected according to the size of the product.
(2) For bolts, studs, screws, nuts and special-shaped non-standard parts based on 35CrMo, 40Cr, 20MnTiB, etc., the quenching medium used is as follows.
① The products are mainly 35CrMo and 40Cr, and you can choose KR118 quick quenching oil or 5%-10% KR6480 polymer water-soluble quenching agent.
②The products are mainly 20MnTiB and 35VB, and quenching agents such as KR7280 or KR6480 can be selected.
(3) Shallow carburized self-tapping screws, pins, etc., based on low-carbon steel 10, 15, 20, 20Cr, 1018, 1022, 10B21, etc., can be selected as quenching agents such as KR6480 or KR118.
(4) Spring washers and retaining rings mainly made of 65Mn, 60Si2Mn, 70 steel, etc., can choose KR118 quick quenching oil.
(5) KR1188 or KR6480 can be selected for more product types and larger size spans, which can meet the quenching and carburizing quenching quality of all alloy steels and carbon steels of a certain size.