PROCESSING SPECIFICATION
Sizes, Grades and Checks for Heat Treated Bars
What we run today, and what we check on every lot.
| Scope | Typical range / requirement | Output | Checks / records |
|---|---|---|---|
| Input material | Carbon · alloy · bearing steel bars | Heat-treated bar to order | Grade · starting condition |
| Conditions | Annealed · normalised · quenched & tempered | Specified mechanical condition | Hardness · tensile as specified |
| Inspection | Grade standard / customer drawing | Traceable processed bars | Certificate · test report as specified |
How We Do It
Carbon, alloy or bearing steel bar in a condition ready for the treatment.
Heat Treated Bars
Bar supplied annealed, normalised or Q&T, with hardness and test results on the certificate.
- Match the grade to the target hardness and section size. Hardenability decides how deep the bar hardens.
- Heat treat: anneal, normalise, or quench and temper.
- Straighten the bar if the treatment needs it.
- Test hardness, plus tensile where specified, and issue the certificate.
Why Use Heat Treated Bars?
Heat treating the bar before you machine it gives you a known strength and hardness from the first cut, and a bar that is ready for heavy duty parts such as shafts, axles and gears.
When Should You Choose It?
Order annealed bar for easy machining and normalised bar for a uniform structure. Order Q&T bar when the part needs strength and toughness without hardening after machining. For surface-hard parts, case-hardening grades are carburised after machining instead.
Common Questions
What is quenching and tempering?
Quenching heats steel and cools it fast to harden it. Tempering reheats it to a lower temperature to remove brittleness. Together they give a strong, tough steel.
What does quenching and tempering do?
It raises strength and hardness and keeps toughness. The tempering temperature sets the balance: lower gives a harder steel, higher gives a tougher one.
What is quenched and tempered steel used for?
Q&T steel is used for shafts, axles, gears, bolts, crankshafts and other parts that carry high loads. Common grades are EN8, EN19, EN24 and EN31.
What steels can be heat treated?
Medium carbon and alloy steels harden well by quenching. Low carbon steels do not, so they are case hardened instead. Stainless steels depend on the family.
What is the difference between hardening and tempering?
Hardening makes steel hard and brittle by fast cooling. Tempering reheats it to cut the brittleness and set the final strength and toughness.
What is the difference between annealed and heat treated steel?
Annealing is a heat treatment. It softens steel for machining. "Heat treated" usually means hardened and tempered, which makes steel stronger and harder.
How is steel heat treated?
The bar is heated to a set temperature, held, then cooled at a set rate. Quenching uses oil or water. Annealing uses slow furnace cooling. Normalising uses air cooling.
What checks come with heat treated bars?
Every lot carries a certificate with the heat treatment condition and the hardness. Tensile and other tests are available when specified.