Ball Screw Material Bearing Steel Characteristics
The quality of a ball screw is not only related to its production process, but also has a lot to do with the raw materials used. Bearing steel is one of the common ball screw materials, so what are the characteristics of this material? ?
The physical properties of bearing steel are mainly based on the inspection of microstructure, decarburization layer, non-metallic inclusions and low magnification structure. Under normal circumstances, they are delivered by hot rolling annealing and cold drawing annealing. The delivery status should be stated in the contract. The low-magnification structure of the steel must be free of shrinkage cavities, subcutaneous bubbles, white spots and microscopic pores. Central looseness and general looseness shall not exceed grade 1.5, and segregation shall not exceed grade 2. The annealed structure of the steel should be uniformly distributed fine-grained pearlite. The depth of the decarburized layer, the non-metallic inclusions and the unevenness of carbides shall comply with the relevant national standards.
Bearing steel is divided into fully hardened bearing steel, carburized bearing steel, stainless bearing steel and high temperature bearing steel according to chemical composition, performance, processing technology and application. The fully hardened bearing steel is mainly high carbon chromium steel, such as GCr15, which has a carbon content of about 1% and a chromium content of about 1.5%. In order to improve hardness, wear resistance and hardenability, appropriately add some silicon, manganese, molybdenum, etc., such as GCr15SiMn. The production of this type of bearing steel is the largest, accounting for more than 95% of all bearing steel production. Carburized bearing steel is a chromium, nickel, molybdenum alloy structural steel with a carbon content of 0.08 to 0.23%. The surface of the bearing parts is carbonitrided to improve its hardness and wear resistance. This steel is used for manufacturing Large bearings subjected to strong shock loads, such as large rolling mill bearings, automobile bearings, mining machine bearings and railway vehicle bearings, etc. Stainless bearing steels include high carbon chromium stainless bearing steels, such as 9Cr18, 9Cr18MoV, etc., and medium carbon chromium stainless bearing steels, such as 4Cr13, etc., which are used to make stainless and corrosion-resistant bearings. High-temperature bearing steel is used at high temperature (300~500℃), which requires steel to have a certain red hardness and wear resistance at the service temperature. Most of them use high-speed tool steel instead, such as W18Cr4V, W9Cr4V, W6Mo5Cr4V2, Cr14Mo4 and Cr4Mo4V, etc.
Bearing steel has good wear resistance, low friction coefficient, high hardness, high elastic limit, good impact toughness and fracture toughness, and the quality of the ball screw made from it is also very high-quality.