A, definitions,
Spring steel refers to the steel specially used to make spring elastic elements due to its elasticity in the quenching and tempering states.The elasticity of steel depends on its elastic deformation capacity, that is, within the specified range, the elastic deformation capacity makes it bear a certain load, and no permanent deformation occurs after the load is removed.Spring steel shall have excellent comprehensive performance, such as mechanical properties (especially elastic limit, strength limit and yield ratio), anti-elastic and anti-elastic properties (i.e. anti-elastic and anti-loose properties), fatigue properties, quenching properties, physical and chemical properties (heat resistance, low temperature resistance, oxidation resistance, corrosion resistance, etc.).In order to meet the above performance requirements, spring steel should have excellent metallurgical quality (high purity and uniformity), good surface quality (strict control of surface defects and decarburization), and accurate external dimensions.
According to GB/T 13304 steel classification standard, spring steel belongs to mechanical structure steel according to basic performance and service characteristics.According to the quality grade, it belongs to special quality steel, that is, steel with special strict control of quality and performance in the production process.According to our custom belong to special steel.
Second, the classification of
(1) classification by chemical composition
According to GB/T 13304 standard, spring steel is divided into non-alloy spring steel (carbon spring steel) and alloy spring steel according to its chemical composition.
Carbon spring steel
Carbon content (mass fraction) of carbon spring steel is generally 0.62%~0.90%.According to its manganese content, it is divided into general manganese content (mass fraction) (0.50%~0.80%) such as 65, 70, 85 and higher manganese content (mass fraction) (0.90%~1.20%), such as 65Mn.
2. Alloy spring steel
Alloy spring steel is a kind of steel based on carbon steel, which can improve its mechanical properties, quenching and other properties by adding one or more alloy elements to meet the requirements of various springs.
The basic composition of alloy spring steels include: silicon-manganese spring steels, silicon-chromium spring steels, cr-manganese spring steels, cr-v spring steels, stelli-chrome v spring steels, etc.Based on these series, some brands have added alloy elements such as molybdenum, vanadium or boron to improve their performance in some aspects.
In addition, from other types of steel, such as quality carbon structural steel, carbon tool steel, high-speed tool steel, stainless steel, choose some brands as spring steel.
(2) classified according to the production and processing methods
1. Hot-rolled (forged) steel includes hot-rolled round steel, square steel, flat steel, steel plate, forged round steel and square steel.
2. Cold drawn (rolled) steel products include steel wire, steel strip and cold drawn steel (cold drawn round steel).
(3) classified according to the payment status of steel
1) hot rolled (forged) steel
2) hot rolled (forged) steels are made into springs, which are then quenched and tempered.
Above all should accord with the corresponding delivery state hardness regulation.Cold drawn (rolled) steel
1) steel wire
When the spring is made of the lead bath isothermally quenched cold drawn steel wire (also known as pyden process cold drawn steel wire), the steel wire can be tempered at low temperature to eliminate the stress.
After the hardened and tempered steel wire is cold-drawn to the required size, the steel wire is subjected to continuous heating, continuous oil quenching and lead tempering.When steel wire is made into a spring, low temperature tempering is required to eliminate stress.
Metal wire (i.e., steel wire not hardened and tempered)
A. Deliver in cold drawn condition
B. Delivery shall be made under annealing, normalizing or tempering conditions
The steel wire in the above two states shall be hardened and tempered after being made into spring.
2) steel belt
To eliminate stress, low temperature tempering is required when the spring is made from the cold rolled spring.
After the quenching and tempering of the impeller is delivered into the spring, low temperature tempering is required to eliminate stress.
The spring shall be hardened and tempered after the annealing condition is delivered.
3) cold-drawn steel
The steels are cold-formed into springs and then hardened and tempered.
(4) other classification methods
In addition to the above, there are other classification methods, such as:
According to the requirements of delivery conditions can be divided into chemical components (mechanical properties) delivery and delivery according to hardenability
According to the working conditions of spring, it can be divided into spring steel with static load, spring steel with impact load, spring steel with high (low) temperature and corrosion resistance.