1. Grade 65, 70 and 85
High strength, hardness and yield ratio can be obtained, but the hardenability is small, the heat resistance is not good, the ability to bear dynamic load and fatigue load is low. It is widely used in small springs with low working temperature or large springs which are not important. Such as automobile, tractor, railway vehicle and general mechanical spring.
65Mn has simple composition, better hardenability, comprehensive mechanical properties, decarburization and other process properties than carbon steel, but it is more sensitive to overheating, has temper brittleness, is easy to crack after quenching, has low price and large amount. It can also make valve spring, spring ring, shock absorber, clutch spring, brake spring, etc.
2. 55Si2Mn 、60Si2Mn 、60Si2MnA
The silicon content (WSI) is high (up to 2.00%).
High strength and good elasticity. Good tempering stability. Easy decarburization and graphitization. Hardenability is not high.
The main spring steel is widely used. Manufacture all kinds of spring, such as leaf spring and coil spring of automobile, locomotive and tractor, cylinder safety valve spring and some important spring working under high stress, and spring with serious wear.
The hardenability of 55si2mnb is obviously improved because of its boron content.
The steel grade 55si2mnb developed by China has better hardenability, comprehensive mechanical properties and fatigue properties than 60Si2Mn steel. It is mainly used to manufacture leaf springs for medium and small-sized automobiles. It can also be used to make other leaf springs and spiral springs with medium cross-section size.
3. 60Si2CrA 60Si2CrVA
High strength spring steel. It has high hardenability and good heat treatment performance. Due to its high strength, it is necessary to eliminate the internal stress after rolling the spring to make the important large spring with large load. 60si2cra can be used for steam turbine seal spring, regulating spring, condenser support spring, high pressure water pump disc spring, etc. 60Si2CrVA steel is also used to make very important springs, such as spring of conventional weapon spring and crusher spring.
The outstanding advantages of 60CrMnA are good hardenability, good hot working performance, comprehensive mechanical properties, anti decarburization performance, and various important springs with large cross-section, such as large leaf spring and spiral spring of automobile and locomotive.
The hardenability is the highest among all kinds of spring steels available. Mechanical properties, anti tempering stability is also good, large-scale civil construction, heavy vehicles, machinery, such as the use of super large springs. The thickness of steel plate can be more than 35mm, and the diameter of round steel can be more than 60mm.
A small amount of vanadium improves elasticity, strength, yield ratio and elastic reduction resistance, refines grains and reduces decarburization tendency. The plasticity and toughness of spring steel are better than that of other spring steels. All kinds of important helical springs with high hardenability and fatigue performance are especially suitable for springs with high working stress amplitude and strict fatigue performance requirements, such as valve spring, fuel injector spring, cylinder expansion ring, safety valve spring, etc.
The hardenability is higher than that of 60CrMnA, and other leaf springs, spiral springs and torsion springs with similar properties and larger sizes are used.
High strength heat resistant spring steel. Good hardenability. High temperature anti relaxation and hot working performance is also very good, working temperature below 500 ~ C heat resistant spring, such as steam turbine main steam valve spring, steam seal spring, boiler safety valve spring, 400t boiler disc valve spring, etc.