CHQ wire grades: choosing steel for cold heading

Cold heading quality (CHQ) wire is steel wire made for cold forging: clean, with a controlled surface, tight size tolerance and a structure that can take heavy deformation. Choosing the grade is a balance between formability and final strength.

Common families

• Low-carbon grades (for example 1010, 1018) — very formable, for parts that do not need heat treatment, such as rivets, low-strength screws and many wire forms.
• Medium-carbon manganese grades (for example 1022, 1541) — for parts heat treated to medium and high strength.
• Boron grades (for example 10B21, 15B25) — low carbon for easy forming, hardenable to high strength classes such as 10.9.
• Alloy grades (for example 4140, SCM435) — chromium-molybdenum steels for the highest strength and larger sections.
• Case-hardening grades (for example 16MnCr5, 20MnCr5) — for parts with a hard, wear-resistant skin and a tough core.

Condition matters as much as grade

For severe forming the wire is spheroidise annealed so the carbides are round and the steel is soft and ductile. The wire is then pickled, coated (phosphate or lime) for lubrication and drawn to the final size.

Standards and values are summarised for general guidance — always work to your drawing and the current edition of the standard. Related REL page.