What is Cr-Mo alloy steel mill liners?

Cr-Mo alloy steel is short for chromium-molybdenum steel. In Australian and New Zealand Standard, it is the AS2074 steel standard; In the USA, it is the BS3100 steel standard. Because Cr-Mo steel has good wear resistance, toughness, and hardness, this steel widely used in casting mill liners for autogenous mills, semi-autogenous mills, ball mills, rod mills, and Vertimills.

  • Low Carbon Chrome Moly Steel (300 to 370BHN): Was generally used for mill liners (AG mill, SAG mill, and Ball mill) prior to the movement to higher carbon content steels. It has excellent wear characteristics with some impact resistance, generally now used for discharge grates where slightly better impact resistance is required compared to the higher carbon chrome-moly steels or for thinner section liners.
  • High Carbon Chrome Moly Steel (325 to 380BHN): This steel is now considered the main material used for SAG mill liners. There are a number of variations with either different carbon or chrome contents. The variations tend to have a bearing on the size of the liner and its section thickness. There is ongoing development within this area as the size of the liners are outstripping the properties provided by the standard high chrome-moly steels.

 

Cr-Mo alloy steel Mill Liners chemical composition and Specification

In Australian and New Zealand Standard, it is AS2074 L2A, AS2074 L2B, and AS2074 L2C. In the USA, it is BS3100 BW2, BW3, BS3100 BW4.

Material Composition

NameChemical Elements(%)
CSiMnCrMoCuPS
AS2074 L2B0.4-0.8≤1.20.6-1.54-60.3-10.3-0.8≤0.04≤0.06
AS2074 L2C0.3-0.6≤1.20.5-1.21.2-2.50.3-10.3-0.8≤0.04≤0.06

 

Physical Property & Microstructure

NameSurface(HRC)Ak(J/cm2Microstructure
AS2074 L2B≥48≥20M+C
AS2074 L2C≥40≥30M+C

 

Specification

SizeHole Dia.(mm)Liner Length(mm)
≤40≥40≤250≥250
Tolerance+2

0

+3

0

+2+3