ISO

P

Material Group - Bearing Steel

The main requirements of bearing steel are high hardness, elastic properties, Resistance to fatigue and contact fatigue failure. These requirements are satisfied by high carbon alloy steels

Chemical Composition
Bearing steel has carbon content in the range of 0.55 to 1.10 percent, manganese, silicon, phosphorus and sulfur up to a maximum of 0.03 percent and chromium in the range of 0.5 to 2.0 percent. The remaining percent is iron. The chemical properties determine the anti-corrosive properties of the bearing steel. The chemical composition of the steel also dictates its mechanical and physical properties such as the strength and hardness, toughness and brittleness and ductility and malleability.

Hardness
Bearing steel has enormous hardness. A minimum expected hardness for bearing components is 58 Rc Bearing steel has a bending strength of 2400 MPa (Pascal Unit) and can withstand high stress and centrifugal forces. But it has a low corrosion resistance
Carbon increases the strength of bearing steel. Strength ensures that parts (i.e., bearings) made from it do not deform on the application of stress and load. Ductility and weldability, however, decrease with increasing carbon content. In addition to this, bearing steel is designed to have high fatigue strength and life and needs to respond uniformly to the heat treatment process. It should have a compact structure with a consistent grain flow and a fine grain size that imparts high impact toughness to the alloy.

Physical Properties
Bearing steel is magnetic in nature and is a good thermal and electrical conductor.

Steel Grade - API Standard

Pipe material depends on application

API Spec.	Pipe Application	Description	Pipe Structure	Material Group	Steel Grade According to API standard
5D	Drilling	Both pipe ends undergo the upsetting process. The drill bit is friction-welded to the end of the pipe. The thick pipe wall provides high distortion resistance.		Group 1	E75
				Group 2	X95, G105, S135
5CT	Casing	Used as an outer protective covering for the pipe. Tubing pipe runs through the center, the casing protects it. Main sizes of casing pipe - Surface Casing: 13⅜ to 24”, Intermediate Casing 9 ⅝”, Production Casing 5 ½ to 7”		Group 1	J55, K55, N80
				Group 2	M65, C75, C75 9Cr & 13Cr, L80, L80SS, C90, C95, C95SS, C95 9Cr & 13Cr, C110, T95
	Tubing	Used in production lines, the crude or gas flows through it. Main sizes of casing pipe, from 2 ⅜ to 5 ½”.		Group 3	P105, P110
				Group 4	Q125 (types 1, 2, 3 & 4), Q125-1
5L	Line	Normally used to transport the crude or gas to the refining plant. This type of pipe is used offshore and onshore, in extreme weather conditions. They are protected by a thick coating. Main sizes of line pipe, from 2 ⅜” to 80”.		PSL 1	A25, A, B ,X42, X46, X52, X56, X60, X65, X70
				PSL 2	B, X42, X46, X52, X56, X60, X65, X70, x80