The metallurgy
Why this family exists
Case hardening steels solve a contradiction. A gear tooth needs a surface hard enough to resist pitting and wear for millions of cycles, and simultaneously a core tough enough to absorb shock without cracking. No single hardness value delivers both.
The answer is a low carbon alloy steel that is carburised: carbon is diffused into the surface at high temperature, then the part is quenched. The carbon-rich case transforms to hard martensite while the low carbon core stays tough. Chromium and manganese in the alloy give the depth of hardening that plain carbon steel simply cannot reach.
These are the highest-value grades Kalika produces, and the most demanding. They go into automotive transmissions, where a supply chain running IATF 16949 requires every batch to be documented back to its original heat — which is exactly what our traceability system was built to provide.
The grades
3 grades in this family
Side by side
Choosing within the family
| Property | 16MnCr5 | 16MnCr5H | 20MnCr5 |
|---|---|---|---|
| Key advantage | Hard wearing surface over a shock-tolerant core | Certified Jominy band — the carburising cycle stays valid batch to batch | Core strength up to 1300 MPa with deeper hardening |
| Machinability | 58 · Moderate | 58 · Moderate | 52 · Fair |
| Weldability | Limited | Limited | Limited |
| Condition supplied | Cold Drawn / Annealed (supplied soft for machining) | Cold Drawn / Annealed (supplied soft for machining) | Cold Drawn / Annealed (supplied soft for machining) |
| Primary use | Gears, gear blanks and pinions | Automotive transmission gears and pinions | Heavily loaded gears and pinions |
Chemical composition and mechanical properties shown are as per the applicable standard and are indicative. Actual values for your consignment are certified in the Mill Test Certificate supplied with each dispatch. Available sizes and tolerances are confirmed at the time of enquiry.
Other families
Looking for something else?
Low Carbon
Weldable, formable and economical — the workhorse grades for general engineering.
MS · SAE 1018
Medium Carbon
Through-hardenable strength for shafts, axles and spindles that carry real load.
EN8 · EN8D · EN8M
Free Cutting
Built to be cut fast — the highest-volume grades on any automatic turning shop floor.
EN1A · EN1A PB
Need a case hardening grade?
Send us the grade, shape, size and quantity. If you are not sure which grade fits, tell us what you are manufacturing.