Knowledge centre
Straight answers to the questions buyers, engineers and students ask us about how steel wire is made and chosen.
Basics
Steel wire that has been cold-drawn through a die after the scale has been removed. Compared with hot-rolled rod it has a smooth, bright surface, a precise diameter and higher strength. It is the raw material for cold-forged, cold-headed and machined parts.
Process
Mill scale is harder than steel and would wear the dies and scratch the wire. Pickling dissolves it; phosphating then adds a coating that carries lubricant into the die.
Grades
For property class 10.9 and above, SAE 4140 or boron steel are the usual choices. Boron steel heads more easily and costs less; 4140 gives deeper hardening for larger sections. Use the grade finder or ask us.
Buying
Grade, finished diameter, quantity (per month or per order), the end application and the delivery location. If you have a drawing or a specification, share that too.
Glossary
Mill scale
Iron oxide layer formed on hot-rolled steel as it cools.
Pickling
Removing scale by dissolving it in acid.
Phosphating
Growing a crystalline phosphate coating that carries drawing lubricant.
Annealing
Heating and controlled cooling to soften steel and relieve stress.
Spheroidising
Annealing that turns plate-like carbides into round particles for better cold forming.
Pearlite
Layered structure of ferrite and iron carbide in carbon steel.
Bell furnace
Batch furnace where a heating bell is lowered over a stack of coils.
Reduction of area
How much the cross-section shrinks in a drawing pass, in per cent.
Cold heading
Forming a part (like a bolt head) from wire at room temperature by upsetting.
Carburising
Adding carbon to the surface of low-carbon steel so it can be hardened into a wear-resistant case.
Heat number
Identifier of the mill melt the steel came from, used for traceability.
Q&T
Quench and temper: hardening then tempering to reach strength with toughness.
Enquiries
We come back with availability and a quotation — usually the same working day.