CS80 Spring Steel – AISI 1075 Steel UK


CS80 carbon steel is a spring steel grade within BS1449. It is a close equivalent to C75S and AISI /SAE 1075, and closely matches EN42.

CS80 spring steel is usually supplied in the hardened and tempered condition. 

It is widely used for the manufacture of flat springs, knives and blades. It has gained popularity in recent years, as whilst it was notoriously difficult to cut, the advent of laser and water jet cutting techniques have largely overcome this issue.

Our material is precision rolled with a good surface finish, close thickness tolerance and good flatness.


Carbon – 0.75 – 0.85%
Manganese – 0.5 – 0.9%
Silicon – 0.05 – 0.35%
Phosphorous – 0.045% max 
Sulphur – 0.045% max

AISI / SAE 1075

Our range

We supply CS80 Spring Steel in coil up to 2mm gauge. The hardness range is 400/440 vpn CS80 is available in sheet 0.25mm – 1mm gauge from stock.

We do not supply Mill Certificates with orders, we only supply Certificates of Conformity.