Cold Rolled or Galvanized Choosing the Right Substrate
Uncoated cold rolled strip is cheaper per tonne, but the comparison only makes sense once the cost of coating the finished part is included. This guide sets out where each one belongs.
The Decision Is About Where the Coating Happens
Both materials start as cold rolled low carbon steel. The difference is whether zinc goes on at the mill, before you form the part, or whether you apply a finish yourself afterwards. Everything else follows from that.
Where Uncoated Cold Rolled Wins
Choose DC01 to DC06 when the part is enclosed, when it will be painted or plated anyway for appearance, or when you need to go below 0.15 mm. The DC ladder reaches 0.05 mm, which is thinner than any galvanized grade we supply, and it draws deeper because there is no coating to crack.
Where Galvanized Wins
Choose DX51D to DX56D when the part is exposed, when its interior surfaces cannot be reached after assembly, or when a separate coating line is a bottleneck. Sacrificial zinc also protects small scratches and cut edges, which no applied paint film does.
The Formability Ladders Run in Parallel
DC01 to DC06 and DX51D to DX56D are the same idea applied to two substrates. If a part draws successfully in DC04, its galvanized equivalent sits around DX53D or DX54D, allowing for the coating. Moving between the two families is therefore a smaller change than it looks.
Do Not Forget the Gauge Limits
This is where the choice is sometimes made for you. Cold rolled DC grades run 0.05 mm to 1.0 mm. Galvanized DX grades start at 0.15 mm. If the part needs 0.1 mm, the substrate question is already answered.
Follow Up Questions
Is galvanized always more expensive than cold rolled?
Can I form galvanized as deeply as uncoated steel?
Materials Covered Here
Sectors This Applies To
Apply This to Your Own Part
A guide can only go so far. Send the part and we will tell you which way the decision goes in your specific case.