2023-12-27 17:37:00 Jinghong

How To Use Screw Product To Maintain Have Coup

Screw standards are: product name (standard), material, strength class, specifications and surface treatment
1. In terms of product type, the torque of the outer hexagon screw is relatively larger, the torque of the inner hexagon screw is relatively smaller, and the torque of the cross groove is smaller.
In the product matching use, we generally recommend to choose the screw grade is higher than the nut grade, so * with economic benefits.
2, the product material grade, here is mainly about our hongyi screw commonly used carbon steel, according to the level of carbon content, we are divided into: C1008(corresponding to grade 4.8), C1035(corresponding to grade 8.8), C1045(corresponding to grade 10.9), SCM435(corresponding to grade 12.9 and 45H), the higher the carbon content, the harder the material.
All screws from grade 8.8 to above are high strength screws.
3. For specifications, such as M4x8, 4 refers to the outside diameter of the tooth is 4mm, and 8 refers to the effective length of the embedded object is 8mm. Generally, the total length of countersunk head screws is loaded.
The pan head screw cross does not contain head dimensions.
4, the same material to do heat treatment, the higher the hardness, the worse the toughness.
Grade 8.8 to above electroplating shall be heat treated.
There are two kinds of heat treatment we do at present: high strength screws need tempering heat treatment, that is, the hardness of screws from inside to outside is uniform;
Self-tapping nails require carburizing heat treatment, that is, the surface of the screw carburized a layer of carbon, very hard, but the inside is very soft, if carburized to the inside the screw will be burnt.
5. Generally, hardness >32HRC, electroplating has hydrogen embrittlement risk.
Hydrogen embrittlement is the product pickling (oil), H+ into the metal to form bubbles, the screw in use on the spot, 24 hours before breaking.
Therefore, the product with the risk of hydrogen embrittlement needs to be dehydrogenated after electroplating.