Also named martensitic or quench hardening, neutral hardening is a heat treatment used to achieve high hardness/strength on steel. It consists of austenitising, quenching and tempering, in order to retain a tempered martensite or bainite structure.
There are several benefits of neutral hardening, depending on the steel type:
-Heavy loaded parts can be given an optimal combination of high strength, toughness and, if applicable, temperature resistance
-Such parts can be made lighter and more stiff, due to higher strength
-Tools and dies get the required high wear and/or heat resistance while maintaining toughness
-Parts that need grinding to low roughness, acquire the required machinability
-For all these purposes, if the parts are made of martensitic stainless steels, the corrosion resistance is only available after the heat treatment
Tool steels: the desired properties of high hardness, wear resistance, heat resistance and machinability can only be given by hardening.
Martensitic stainless steels: these steels only get their maximum corrosion resistance by hardening.
For all steel types: during the shaping of the parts, (takes place before the heat treatment), the material is relatively soft and therefore easy to machine.
Application & materials
-Highly loaded parts, such as drive shafts, carrier bars, frames, fork lift forks, nuts and bolts, lifting eyes etc.
-Similar parts, intended for elevated temperatures
-Springs of any kind, and any dimension
-Tools: cutting, hammering, rolling i.e. any kind of tooling for cold, as well as for hot working