Introduction to the material characteristics of the hardware spring “spring wire”
Spring steel wire is a kind of steel wire used to make springs (SPRING) or wire-shaped parts (WIRE FORM). According to the different uses of springs, there are many types of spring steel wires needed to make springs, such as mattress springs with lower requirements. The spring wire (the mattress wire for short), the spring wire for shock absorber, the spring wire for suspension spring, the spring wire for engine valve and the spring wire for camera shutter, etc., although there is no unified standard classification name, these The quality requirements of the steel wire are different. Spring steel wire can also be classified according to the manufacturing process, such as raw drawn spring steel wire (without lead bath quenching treatment before drawing), lead quenched spring steel wire, galvanized spring steel wire, oil quenched spring steel wire, etc.
Use characteristics and uses of spring steel wire
The spring is used within the elastic range and should return to its original position after unloading. It is hoped that the smaller the plastic deformation, the better, so the steel wire should have a high elastic limit, yield strength and tensile strength. The higher the yield ratio, the closer the elastic limit is Tensile strength, so the more the strength utilization can be improved, the stronger the spring force.
The spring usually works for a long time under the action of alternating stress, so it must have a high fatigue limit, and good creep resistance and relaxation resistance.
Springs used in specific environments have some special requirements for steel wires. For example, springs used in corrosive media must have good corrosion resistance. Springs used in precision instruments should have long-term stability and sensitivity. , The temperature coefficient should be low, the quality factor should be high, the after-effect should be small, and the elastic modulus should be constant. Springs that work under high temperature conditions are required to maintain sufficient elastic limit and good creep resistance at high temperatures. .
The spring relies on elastic deformation to absorb impact energy, so the spring steel wire does not have to have high plasticity, but at least it must have plasticity that can withstand spring forming, and sufficient toughness to withstand impact energy.
In addition, the forming process and heat treatment process of the spring steel wire should also be considered. Both cold drawn spring steel wire and oil quenched tempered spring steel wire are directly wound with the steel wire in the state of supply, and the spring is directly used after stress relief treatment after it is formed. The tensile strength of steel wire is slightly higher than that of oil-quenched and tempered steel wire.
Large-size cold-drawn steel wire has too much elasticity and it is difficult to wind the spring. Therefore, the specification of cold-drawn spring steel wire is generally less than 8.0mm, and the specification of oil-quenched and tempered steel wire is generally less than 13.0 mm. In fact, springs with a diameter of 13.0mm are mostly spring steel wires in the lightly drawn state, which are cold-drawn and wound into shape and then quenched and tempered for use. Most of the steel wires with a diameter of 15.0mm are made by heating winding technology.