Application
Gears & Transmission Components
Carburised gears and pinions, where case depth consistency and traceability decide whether the batch is accepted.
The requirement
What this application actually demands
A gear tooth has to survive two entirely different loads at the same time. The flank is rubbing and rolling against a mating tooth for millions of cycles and needs a hard, wear-resistant surface. The root is bending in fatigue and taking shock, and needs a tough core that will not crack.
No single hardness satisfies both. The answer is a low carbon alloy steel that is machined soft, carburised to build a hard case, then quenched and tempered — hard skin, tough core.
The hard part of making this work in production is consistency. A gear plant proves a carburising cycle once and then wants to run it. If the incoming steel hardens to a different depth from one batch to the next, case depth drifts out of drawing tolerance and gears are rejected after all the value has already been added to them.
That is exactly the problem 16MnCr5H solves, and it is why gear manufacturers under IATF 16949 specify the H grade rather than plain 16MnCr5.
Grade selection
Recommended grades, and why
16MnCr5H
First choice16MnCr5H Hardenability Controlled Alloy Bright Bar
Machinability 58 · Weld Limited
The correct specification for volume gear production. Certified Jominy hardenability band means the proven carburising cycle keeps producing the same case depth batch after batch.
16MnCr5
16MnCr5 Case Hardening Alloy Bright Bar
Machinability 58 · Weld Limited
The general purpose carburising alloy for moderately loaded gears and gear blanks where a certified hardenability band is not a contractual requirement.
20MnCr5
20MnCr5 Case Hardening Alloy Bright Bar
Machinability 52 · Weld Limited
For heavily loaded teeth and larger sections. Higher carbon and chromium give core tensile up to 1300 MPa and deeper hardening through thicker gear blanks.
Heat number carried through to your gate
Case study
Read the full case study“Consistent hardenability across every batch — with full traceability for our IATF audit.”
Other applications
Also making something else?
Fasteners
High-volume turned and cold formed fasteners, where cycle time decides the cost per piece.
Shafts & Axles
Torque carrying and fatigue loaded components, where through-section strength and straightness matter.
Auto Components
Tier-1 and Tier-2 automotive parts, where documentation is part of the product.
Hydraulic & Pneumatic
Sealing surfaces and pressure-carrying parts, where surface finish and tolerance are the specification.
General Engineering
The broad base of engineering work — machined parts, fabricated assemblies and everything in between.
Supplying into gears & transmission?
Send us the grade, size and quantity — or tell us the component and we will recommend the grade.