Istanbul
Production Facility

Process Advantage

Salt Bath Hardening —
Dimensional Stability by Design

After forming, all Isco steel toecaps undergo hardening. The choice of quenching medium has a decisive effect on the dimensional stability of the finished component — and Isco uses salt bath hardening (marquenching) for precisely this reason.

In conventional oil bath quenching, a vapour blanket forms on the surface of the component during the initial cooling stage. This vapour layer creates non-uniform heat extraction across the part — the surface cools at a different rate from the core, generating internal stress gradients that cause distortion and dimensional variation.

Molten salt baths have no vapour phase. The heat transfer is immediate, uniform and consistent across the entire surface and cross-section of the part — and the buoyancy of the salt bath physically stabilises the component during cooling, mechanically preventing sag and warping.

The result: more predictable post-hardening dimensions, batch after batch — which means the toecap fits your last accurately, every time, without secondary straightening operations or dimensional rejects.

This is confirmed in peer-reviewed metallurgical literature, ASM International proceedings, and across the commercial heat treatment industry: "A part quenched in salt will experience less distortion than that same part quenched in oil."