CS4 Mild Steel

About CS4 Mild Steel

CS4 is a cold rolled mild steel traditionally used for cold forming. Cold-rolled steel is about 20% stronger than hot-rolled steel through the use of strength hardening. Cold-rolled steel can be further heat-treated by the customer.

It is a soft steel with a high ductility level and a low carbon content. 

Whilst the advent of newer steels have largely replaced CS4 for a lot of manufacture, it still has benefits where a close thickness tolerance is required or where stiffness is an advantage.

BSS holds a range of CS4 mild steel in the full hard rolled condition, with a hardness of 165VPN and tensile strength Rm of 540N/mm². 

CS4 mild steel is part of BS1449.

Typical CS4 mild steel Applications

CS4 mild steel is utilised in standard fabrication and engineering.

It is typically used for the manufacture of shims and washers.

In addition to supplying CS4 in sheet for shim manufacture, BSS can supply laser cut shims – call 0114 244 0527 with your requirements. 

CS4 mild steel Chemical Composition

Carbon – 0.8 – 0.13%
Manganese – 0.3 – 0.4%
Silicon – 0.03% max
Sulphur – 0.03% max

DIN1624
St4
St4/RRSt3
St2

BS1449
CS1
CS1/CS3
CS4

En10139
DC04
DC01



Our range

BSS stock CS4 fully hard rolled from .05mm (.0015″ or 48swg) through to 1.63mm (0.064″ or 16 swg).
We do not supply Mill Certificates with orders, we only supply Certificates of Conformity.