What Is Bearing Strength?

Bearing steel is steel used to make balls, rollers and bearing rings. Bearing steel has high and uniform hardness and wear resistance, as well as high elastic limit. The requirements for the uniformity of the chemical composition of bearing steel, the content and distribution of non-metallic inclusions, and the distribution of carbides are very strict. It is one of the most stringent steel types in all steel production. In 1976, the International Organization for Standardization (ISO) included some common bearing steel numbers into international standards, and divided bearing steel into four types: total hardened bearing steel, surface-hardened bearing steel, stainless bearing steel, and high-temperature bearing steel. Steel number.

Bearing steel is also called high-carbon chromium steel. The carbon content W _c is about 1%, and the chromium content W _cr is 0.5% -1.65%. Bearing steel is divided into six categories: high-carbon chromium bearing steel, chromium-free bearing steel, carburizing bearing steel, stainless bearing steel, medium and high temperature bearing steel and antimagnetic bearing steel.

The high-carbon chromium bearing steel GCr15 is the world's largest-produced bearing steel. The carbon content Wc is about 1% and the chromium content Wcr is about 1.5%. Since its birth in 1901, it has remained basically unchanged for more than 100 years. With the advancement of science and technology, research work continues, and product quality continues to improve, accounting for more than 80% of the world's total bearing steel production. So that if there is no special description of bearing steel, it means GCr15.

China has produced high-carbon chromium stainless bearing steel, the main steel number is 9Cr18; carburizing bearing steel, the main steel number is G20CrMo; chromium bearing steel, the main steel number is GCr15. ^[1]

The physical properties of bearing steel are mainly to check the microstructure,

Bearing steel is divided into fully hardened bearing steel, carburizing bearing steel, stainless bearing steel and high temperature bearing steel according to chemical composition, performance, use processing technology and application. Full 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 the hardness, wear resistance and hardenability, some silicon, manganese, molybdenum, etc., such as GCr15SiMn, are appropriately added. This type of bearing steel has the largest output, accounting for more than 95% of all bearing steel output. Carburizing 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 part is carbonitrided to improve its hardness and wear resistance. This steel is used for manufacturing Large bearings that bear strong impact loads, such as large rolling mill bearings, automotive bearings, mining machine bearings, and railway vehicle bearings. Stainless bearing steels include high carbon chromium stainless bearing steels, such as 9Cr18, 9Cr18MoV, 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 ). It is required that the steel has certain red hardness and wear resistance at the use temperature. Most of them use high-speed tool steel substitutes, such as W18Cr4V, W9Cr4V, W6Mo5Cr4V2, Cr14Mo4 and Cr4Mo4V.

(1) UHP electric furnace smelting of 50 tons and above LF furnace refining of 60 tons and above VD furnace vacuum processing of 60 tons and above continuous casting of alloy steel billet or rectangular billet (260mm × 300mm, 180mm × 220mm) slow cooling or Hot delivery rolling material finishing inspection and storage.

(2) Converter smelting of 90 tons and above LF furnace refining of 100 tons and above RH furnace vacuum treatment of 100 tons and above continuous casting of alloy steel billet or rectangular billet (eg: 320mm × 340mm, 240mm × 240mm) slow cooling Or hot delivery rolling material finishing inspection and storage. ^[2]

Bearing steel is used in manufacturing

The production of bearing steel mainly implements the GB / T18254-2002 standard and the Laiwu Steel GCr15JD quality agreement adapted to the requirements of precision forging bearing users. The quality requirements of the GCr15JD agreement are stricter than the GB / T18254-2002 standard. The GCr15JD requires oxygen content 10ppm and central segregation level. Grade 1.0, composition control, sizing and dimensional deviation are all stricter than GB / T18254-2002 standard.

Bearings are subjected to great pressure and friction during work, so bearing steel is required to have high and uniform hardness and wear resistance, as well as high elastic limit. The uniformity of the chemical composition of the bearing steel,

Production export

China's Dalian Steel Plant, Daye Steel Plant is the main source of bearing steel. Currently it is mainly exported to Hong Kong and Southeast Asia. China mainly imports bearing steel from Japan and Germany.

Product packaging

If the diameter is less than 20mm, it must be delivered in packages. If it is larger than 20mm, it can be delivered in bare packages. Anti-rust oil should be applied to cold drawn steel. The goods shall be accompanied by a quality guarantee certificate indicating the steel number, furnace number, weight, specifications, chemical composition, inspection standards and inspection results before leaving the factory.

Specifications Appearance

The specifications are mainly round steel,

The basic machinery foundry industry such as precision bearings has become a key industry during the "Twelfth Five-Year Plan" period of the country. In order to achieve the economic growth goals proposed by the two conferences, infrastructure construction projects in cities around the city have begun intensively, and the market demand for bearing steel will be released.

With the continuous and rapid development of the bearing manufacturing industry, the bearing steel market is promising. Domestic bearing steel manufacturers are actively developing new bearing steel varieties, and the development of the bearing manufacturing industry based on high-end products is the main trend in the future.

In order to achieve the economic growth targets proposed by the two conferences, infrastructure construction projects in various cities have set off a climax. The intensive start of railways, social housing, water conservancy, ports, airports and other major projects has driven the recovery of construction machinery manufacturing and stimulated demand for construction machinery. The market demand for bearing steel has also been released. At the same time, the market prices of iron and steel raw materials such as iron ore, coke and high chromium continue to run at a high level, which has led to the continuous rise in bearing steel production costs and the promotion of rigid costs, which has led to an increase in the ex-factory prices of steel mills. Two favorable factors have stabilized growth and boosted domestic demand.