Case study
Hydraulic Cylinder Manufacturer
Waluj MIDC, Chhatrapati Sambhajinagar
“Consistent hardness meant we stopped adjusting the tempering cycle for every new lot.”
01
The challenge
The customer manufactures hydraulic cylinders and piston rods for material handling equipment. Rods are hardened and tempered to a specified hardness range, then hard chrome plated.
Working with standard EN8, as-quenched hardness varied enough between lots that the tempering cycle had to be adjusted lot by lot, based on trial pieces. That is slow, and it puts the process at the mercy of whoever is reading the trial results.
They were also seeing occasional plating adhesion issues traced to base surface quality, and rejections from rod straightness affecting seal wear in assembled cylinders.
02
What we changed
Grade supplied
EN8DEN8 held to tighter limits — for parts where batch-to-batch variation costs money.
Consistent hardness batch after batch
We moved them to EN8D — the same medium carbon steel supplied to tighter carbon and manganese bands with phosphorus and sulphur each capped at 0.035%. The narrower chemistry band directly narrows the as-quenched hardness spread.
Rods were drawn to h9 with surface quality and straightness monitored as process parameters, giving a consistent, clean base for hard chrome plating.
Each consignment shipped with the Kalika test certificate and the mill certificate for the heat, so their incoming inspection had documented chemistry rather than an assumed grade.
03
The result
- Tempering cycle stabilised — no per-lot adjustment on trial pieces
- Hardness of finished rods held inside the specified range more consistently
- Plating adhesion issues reduced through consistent base surface quality
- Straightness-driven seal wear rejections reduced
- Incoming inspection time cut, with certified chemistry supplied on every consignment
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.