Case study
Leading Gear Manufacturer
Waluj MIDC, Chhatrapati Sambhajinagar
“Consistent hardenability across every batch — with full traceability for our IATF audit.”
01
The challenge
The customer manufactures transmission gears for a Tier-1 automotive supplier and runs a single proven carburising cycle across the whole product family. Their drawing calls for a case depth held to a narrow band.
They were experiencing case depth drifting outside that band between material batches. Both batches were metallurgically within the 16MnCr5 chemical specification — but one sat near the top of the manganese and chromium ranges and the other near the bottom, and they hardened to measurably different depths on the same furnace cycle.
The consequence was expensive. Rejections were found at final inspection, after machining, carburising and grinding had already been paid for. Each drift also cost engineering time re-proving the furnace cycle against the new lot.
A second problem was documentary. Their IATF 16949 surveillance audit required them to demonstrate, for a sampled batch of finished gears, which heat of steel it originated from. Their existing supplier could produce a mill certificate but could not link a specific delivered bundle to it.
02
What we changed
Grade supplied
16MnCr5HGuaranteed hardenability band — consistent case depth on every batch, every time.
Certified Jominy band — the carburising cycle stays valid batch to batch
We moved them from 16MnCr5 to 16MnCr5H — the hardenability controlled variant. Each heat is Jominy end-quench tested at the mill and certified to fall inside a defined hardness-versus-distance band, so the hardening response is a controlled property rather than an outcome of where the chemistry happened to land.
Material is drawn on a dedicated line pass with the die, line, shift and operator recorded against the heat number in our ERP at the time of production — not reconstructed afterwards.
Every bundle despatched carries a QR tag encoding its heat number. The same heat number is printed on the delivery challan and appears on the Kalika test certificate issued with the consignment, alongside the mill certificate for that heat.
03
The result
- Case depth held inside drawing tolerance across successive batches on the unchanged carburising cycle
- Rejections at final inspection reduced — the drift-driven failure mode was removed
- Furnace cycle no longer re-proved for each incoming lot, releasing engineering time
- Complete batch traceability produced during the IATF surveillance audit, on the day it was requested
- Kalika approved as a documented source for their case hardening alloy requirement
Results described here are those reported by the customer for their process and product. Outcomes on your parts depend on your design, your machining and your heat treatment, and are not guaranteed by the material alone.
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.
Discuss your requirement
Tell us what is happening on your line. If the answer is a different grade, we will say so — including when it is one we do not stock.