Overall Description
| Name | Round Head Phiilips Sems Screw |
| Size | M3.5/customized |
| Material available | Super good stainless steel |
| Surface | Polished, and so on |
| Feature | Screw with captive washer |
| Head type | Round |
| Drive style | Phillips |
| Application | Home appliances, precision institutions, etc |
Details
Production Flow
Partners
After the low carbon and medium carbon (alloy) steels are quenched into martensite, the general rule is that the strength decreases and the plasticity and toughness increase as the tempering temperature increases. However, due to the different carbon content in low and medium carbon steels, the tempering temperature has different effects on them. Therefore, in order to obtain good comprehensive mechanical properties, the following approaches can be taken separately:
(1) Select low-carbon (alloy) steel, and after quenching, temper at a low temperature of 250 ° C or lower to obtain low-carbon martensite. In order to improve the surface wear resistance of such steels, only the carbon content of each surface layer is increased, that is, surface carburization is performed, which is generally called carburized structural steel.
(2) Adopt medium carbon steel with high carbon content, and temper at high temperature (500-650 °C) after quenching (so-called quenching and tempering treatment), so that it can maintain sufficient strength under high plasticity, generally called This type of steel is quenched and tempered steel. If you want to obtain high strength, but prefer to reduce plasticity and toughness, low-temperature tempering can be achieved for gold-containing tempering with lower carbon content, so that the so-called "ultra-high-strength steel" is obtained.
(3) Steel grades with carbon content between medium carbon and high carbon (such as 60, 70 steel) and some high carbon steel (such as 80, 90 steel), if used to manufacture springs, in order to ensure high elasticity At the limit, yield limit and fatigue limit, moderate temperature tempering after quenching is used.
Second, the operation process:
(1) Quenched and tempered steel:
1. Pre-heat treatment: normalizing->annealing (pearlite steel)->high temperature tempering (martensitic steel)
(1) The purpose of normalizing is to refine the grains, reduce the degree of banding in the structure, and adjust the hardness to facilitate mechanical processing. After normalizing, the steel has equiaxed fine grains.