Bearing pipes

Bearing pipe is a kind of seamless steel pipe by hot-rolled or cold-rolled ( cold drawn ), used for the manufacture of ordinary bearing rings. The outer diameter of pipe is usually 25-180 mm and with wall thickness of 3.5-20 mm.

Introduction Bearing steel pipe is a sort of hot-rolled or cold-rolled (cold-drawn) seamless steel tube. Salvaging used for producing general antifriction bearing ferrule. The side diameter is 25 mm to 180 mm along with the thickness is between3.5 to twenty mm.

We mainly provide general precision and high precision bearing steel pipes.

Main Standards for Bearing Steel Pipe

ASTM A295 specification covers high-carbon bearing-quality steel to be used in the manufacture of anti-friction bearings. The most common steel grade in ASTM A295 standard is 52100.

 Relevant Steel Specification of ASTM 52100 Bearing Steel

Country USA German Japan British
Standard ASTM A295 DIN 17230 JIS G4805 BS 970
Grades 52100 100Cr6/1.3505 SUJ2 535A99/EN31

Chemical Composition of 52100 Bearing Steel and Equivalents

Standard Grade C Mn P S Si Ni Cr Cu Mo
ASTM A295 52100 0.93-1.05 0.25-0.45 0.025 0.015 0.15-0.35 0.25 1.35-1.60 0.30 0.10
DIN 17230 100Cr6/1.3505 0.90-1.05 0.25-0.45 0.030 0.025 0.15-0.35 0.30 1.35-1.65 0.30
JIS G4805 SUJ2 0.95-1.10 0.50 0.025 0.025 0.15-0.35 1.30-1.60
BS 970 535A99/EN31 0.95-1.10 0.40-0.70 0.10-0.35 1.20-1.60

Mechanical Propertiesof ASTM A295 52100 Bearing Steel

Properties Metric Imperial
Bulk modulus (typical for steel) 140 GPa 20300 ksi
Shear modulus (typical for steel) 80 GPa 11600 ksi
Elastic modulus 190-210 GPa 27557-30458 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Hardness, Brinell
Hardness, Knoop (converted from Rockwell C hardness) 875 875
Hardness, Rockwell C (quenched in oil from 150°C tempered) 62 62
Hardness, Rockwell C (quenched in water from 150°C tempered) 64 64
Hardness, Rockwell C (quenched in oil) 64 64
Hardness, Rockwell C (quenched in water) 66 66
Hardness, Vickers (converted from Rockwell C hardness) 848 848
Machinability (spheroidized annealed and cold drawn. Based on 100 machinability for AISI 1212 steel) 40 40

52100 Steel Physical Properties

Properties Metric Imperial
Density 7.81 g/cm3 0.282 lb/in³
Melting point 1424°C 2595°F

52100 Alloy Steel Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient (@ 23-280°C/73.4- 36°F, annealed) 11.9 µm/m°C 6.61 µin/in°F
Thermal conductivity (typical steel) 46.6 W/mK 323 BTU in/hr.ft².°F

Forging of A295 52100 Bearing Steel

AISI 52100 alloy steel is forged at 927 to 1205°C, and should not be forged below 925ºC. A post-forge equalization treatment is recommended at 745ºC for 4-6 hours followed by air cooling for SAE/AISI 52100 steel.

Bearing steel is used to make ball, roller and bearing rings of steel. Bearings work under immense pressure and friction, it requires a high and uniform bearing steel hardness and wear resistance, and a high elastic limit. Bearing steel chemical composition uniformity, non-metallic inclusion content and distribution, the distribution of carbides and other requirements are very stringent requirements of all steel production in one of the most demanding steel grades.

Bearing steel has a high smelting quality requirements, meanwhile, and requires strict control of sulfur, phosphorus, hydrogen content, and non-metallic inclusions and carbides of the number, size and distribution, non-metallic inclusions and carbides as the number, size and distribution service life of the bearing steel great influence, often bearing failure is in large carbide inclusions or micro-cracks generated around the extension to.

Inclusions content and oxygen content in steel is closely related to the higher oxygen content, the more the number of inclusions, the shorter life expectancy.

And carbide inclusions larger particle size, more uniform distribution, the shorter the service life, and their size , distribution and use of the smelting process and the smelting quality is closely related to, now bearing steel production as well as the main process is the continuous casting EAF + ESR smelting process, as well as a small amount of vacuum induction vacuum arc double vacuum or + repeatedly vacuum consumable and other technology to improve the quality of bearing steel.

Since the bearing should have a long life, high precision, low heat, high speed, high rigidity, low noise, high wear resistance and other characteristics, thus requiring the bearing pipe should have: high hardness, uniform hardness, high elastic limit, high contact fatigue strength, must toughness, hardenability must be in atmospheric corrosion resistance of the lubricant. To achieve these performance requirements, the chemical composition of steel bearings homogeneity, non-metallic inclusion content and type, size and distribution of carbides, decarburization demanding. Overall bearing steel to high-quality, high performance and multi-species direction. Bearing steel according to characteristics and application environments are divided into: high carbon chromium bearing steel, carburizing bearing steel, high temperature bearing steel, stainless steel and special bearing special bearing materials. To meet the high-temperature, high-speed, high load, corrosion, anti-radiation requirements, need to develop a series of special performance of the new bearing steel. In order to reduce the oxygen content of bearing steel, the development of vacuum smelting, electroslag remelting, electron beam remelting bearing steel smelting technology.

The large quantities of bearing steel smelting by the arc melting, to develop into all types of early Canadian refining furnace.

Seamless pipe Specification, standard and identification

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.