Fastener steel refers to the steel used to make various types of fasteners. Fasteners are a class of mechanical parts used when two or more parts (or components) are tightly connected into a whole, and they are also known as standard parts in the market.
The choice of steel for fasteners depends on many factors, including the type of fastener, the working environment, the expected load and temperature. The following are some common fastener steels and their characteristics:
1. ** high-quality carbon structural steel ** : the most commonly used carbon tempered steel, good comprehensive mechanical properties, low hardenability, easy to crack when water quenching. Tempering treatment should be used for small parts and normalizing treatment should be used for large parts. It is mainly used to manufacture moving parts with high strength, such as turbine impellers and compressor pistons. Shaft, gear, rack, worm, etc.
2. **Q235A (A3 steel) ** : the most commonly used carbon structural steel. It has high plasticity, toughness and welding performance, cold stamping performance, and certain strength, good cold bending performance. Widely used in general requirements of parts and welding structures. Such as tension rod, connecting rod, pin, shaft, screw, nut, ring, bracket, frame, building structure, bridge and so on.
3. **40Cr** : One of the most widely used steel, alloy structural steel. After quenching and tempering treatment, it has good comprehensive mechanical properties, low temperature impact toughness and low notch sensitivity, good hardenability, higher fatigue strength can be obtained when oil is cold, complex shape parts are easy to crack when water is cold, cold bending plasticity is medium, cutting machinability is good after tempering or tempering, but weldability is not good, easy to crack, and should be preheated to 100 ~ 150℃ before welding. It is generally used in the tempered state, and can also be carbonitriding and high-frequency surface quenching treatment.
4. **HT150** : gray cast iron, mainly used for gear box, machine bed, box, hydraulic cylinder, pump body, valve body, flywheel, cylinder head, belt wheel, bearing cover and so on.
5. **35** : commonly used materials for various standard parts and fasteners, with appropriate strength, good plasticity, high cold plasticity, and decent weldability. It can be partially upset and drawn under cold conditions.
