Heat Treatment Damages
Damages due to faulty heat treatment
One of the most important production steps in the manufacture of individual parts, assemblies or large components made of metal is heat treatment. It plays a central role in the adjustment of the material properties.
Heat treatment is a sequence of heat treatment steps in the course of which a workpiece is wholly or partially subjected to time-temperature sequences in order to bring about a change in its properties and/or its microstructure.
In addition, the chemical composition of the workpiece can be changed during the treatment. As in case hardening or nitriding, for example.
Thermal processes include hydrogen relief annealing, stress relief annealing, soft annealing, normalising, coarse grain annealing, diffusion annealing and recrystallisation annealing as well as hardening and tempering (quenching and tempering) and surface hardening.
Damage can often occur due to incorrect temperature control or the setting of the ambient medium, which not infrequently affects complete treatment batches.
- Typical damages are: Incorrect strength and hardness leads to fracture or wear.
- Unfavourable phase formation reduces corrosion resistance
- Coarse grain formation lowers the fatigue strength
- Embrittlement due to hydrogen
- Unfavourable residual stresses
But problems are also to be expected during the subsequent machining of parts: punching, turning, milling, drilling, grinding, polishing are all related to the properties and the basic structure.
Our experts use samples to analyse possible causes of defects. As a rule, metallographic sections are evaluated microscopically. The microstructural images then provide our metallographers and materials experts with information about the history of a component. Heat treatment errors can thus be detected and corrective measures initiated.