s shown in alloy steel wire. In addition, there are also deformation heat treated steel wires under development. Carbon spring steel wire should have high tensile strength, limited elasticity, toughness, and fatigue strength, and be resistant to impact and vibration. The strength and toughness indicators, especially the prevention of torsional cracks, are key to the production of spring steel wires. The internal quality and surface quality of wire rods directly affect the performance of steel wires. The carbon spring steel wire is made of high carbon structural steel or car bon Tool steel wire rod, and its chemical composition, gas content and non-metallic inclusion must be strictly cont rolled according to the use of the spring. In order to reduce surface defects and decarburization layers, the steel billets used for producing wire rods need to be ground on the surface and peeled if necessary. The wire rod shouldundergo normalizing or sorbite treatment, and larger specifications should be replaced by spheroidizing annealing. The heat treatment in the middle, especially before the drawing process of the finished product, is widely used with sorbitization treatment. During heat treatment, decarburization should be prevented. After heat treatment, sulfuric acid or hydrochloric acid pickling is used to remove iron oxide scale. The coating (see lubrication carrier) c an be dipped in lime, phosphating, borax treatment or copper plating. The drawing process of the finished product has a significant impact on product performance. Generally, a larger total reduction rate of about 90% (see areareduction rate) and a smaller pass reduction rate (approximately ≤ 23%) are used to ensure the toughness of the product. For high-strength spring steel wire, the outlet temperature of each pass of steel wire should be controlle d below 150 ℃ during drawing to prevent torsion cracks caused by strain aging, which is the main defect causing steel wire scrap. For this reason, good lubrication and sufficient cooling are necessary during the drawing process. Adopting a smaller pass reduction rate and drawing speed can help reduce the temperature rise of the steel wire. After drawing, there is a large residual stress in the steel wire, which affects its performance. Measures such as online straightening or low temperature (180-370 ℃) heating can be used to eliminate it.

Alloy spring steel wire is made of alloy spring steel such as silicon manganese and chromium vanadium. The softe ning of the wire rod adopts incomplete annealing. During heat treatment, decarburization should be prevented, a nd for silicon containing spring steel wire rods, graphite carbon precipitation should also be prevented. The heat t reatment of semi-finished products adopts recrystallization annealing. The pickling and coating processes are similar to the production of carbon spring steel wires. As needed, silicon manganese spring steel wire can be delivere d in different states such as cold drawn, annealed, normalized, high-temperature tempered, silver bright, and oil quenched tempered; Chromium vanadium spring steel wire is available in delivery states such as cold drawn, annealed, and silver bright. Generally, alloy spring steel wire must be quenched and tempered at medium temperature before use after being wound into a spring.

Quenched and tempered spring steel wire mainly includes oil quenched tempered carbon spring steel wire and silicon manganese alloy spring steel wire, valve oil quenched tempered carbon spring steel wire and chromium silic on alloy spring steel wire. The purpose of oil quenching tempering and tempering treatment for spring steel wire after drawing is to make the steel wire。