CS4 Mild Steel - Cold rolled mild steel

CS4 Mild Steel is a cold rolled mild steel traditionally used in cold forming and fabrication applications. With a low carbon content and high ductility, CS4 is a soft steel that remains easy to work with, yet offers excellent strength through cold rolling.

Cold-rolled steel is approximately 20% stronger than hot-rolled steel due to work hardening, and CS4 can be further heat-treated by the customer if required.

Although newer steel grades have replaced CS4 in many manufacturing sectors, it is still widely chosen for applications where tight thickness tolerances and stiffness are important.

Key Features of CS4 Mild Steel

• Part of BS1449 standard steels
• Carbon content: 0.08–0.13%
• Hardness: 165 VPN
• Tensile strength (Rm): 540 N/mm²
• Cold rolled – ~20% stronger than hot rolled steel
• Excellent ductility for forming and fabrication
• Supplied in fully hard rolled condition

CS4 remains a popular choice for general fabrication and precision engineering. Common uses include:

• Shims (sheet or laser cut)
• Washers
• General cold forming and fabrication
• Precision components requiring close thickness tolerances

At BSS, we can supply CS4 mild steel sheet for shim manufacture, or laser-cut shims to your exact requirements.