Basic knowledge of common fastener products

Basic knowledge of common fastener products
Shenzhen Heat Hardware Co.,Ltd is a screw manufacturer specializing in the production of non-standard screws, stainless steel screws, hexagon socket screws, precision screws, anti-theft screws, special screws, combination screws ,sems screw,security screw,brass screw.micro screw,long screw.machine screw

and other products.

In terms of main product types, the torsion force of the hexagon socket screws is relatively greater, the torsion force of the hexagon socket screws is smaller, and the torque of the cross recess is smaller. In the use of products,

we generally recommend that the grade of the screw is one level higher than that of the nut, which has the most economic benefits.

Basic knowledge of fastener products:
The standards of screws are: product name (standard), material, strength grade, specification and surface treatment

1. In terms of product types, the torsion force of the hexagon socket screws is relatively greater, the torque of the hexagon socket screws is smaller, and the torque of the cross recess is smaller. In the use of products, we generally

recommend that the grade of the screw is one level higher than that of the nut, which has the most economic benefits.

2. Product material grade, here we mainly talk about the carbon steel commonly used by Hongyi screws. According to the level of carbon content, we are divided into: c1008 (corresponding to 4.8 grade), c1035 (corresponding to 8.8

grade), c1045 (corresponding to 10.9 grade) scm435 (corresponding to 12.9 and 45h), the higher the carbon content, the harder the material. Screws of grade 8.8 and above are all high-strength screws.

3. For specifications, such as m4x8, the outer diameter of the 4-finger tooth is 4mm, and the effective length of the 8-finger embedded object is 8mm. Generally, the total length of the countersunk head screw is loaded, and the half

countersunk head screw needs to add half the head. length. The pan head screw cross does not include the head size.

4. When the same material is heat treated, the higher the hardness, the worse the toughness. Heat treatment is required for electroplating from 8.8 to above. We currently do two kinds of heat treatment: high-strength screws require

quenching and tempering heat treatment, that is, the hardness of the screw is uniform from the inside to the outside; self-tapping screws need carburizing heat treatment, that is, the surface of the screw is carburized, which is very
hard , But the inside is very soft, if carburizing to the inside, the screws will be burnt.

5. Under normal circumstances, the hardness> 32hrc, electroplating has the risk of hydrogen embrittlement. Hydrogen embrittlement means that when the product is pickled (oil stain), h+ enters the metal to form bubbles, and the screw is

used continuously on the spot, and it breaks after 24 hours. Therefore, this product with the risk of hydrogen embrittlement requires hydrogen removal after electroplating.