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Heat treatment of steels

Normalization of a heterogeneous microstructure

Normalizing of steel (annealing)

The aim of normalizing is to achieve a uniform homogeneous microstructure with reproducible properties! https://youtu.be/PJ2FKTHAo5s As already explained in the chapter deformability of metals, fine roundish grains generally lead to better toughness and...
Recrystallization annealing of a rolled sheet

Recrystallization annealing of steel

The aim of recrystallisation annealing is to restore a deformed microstructure to improve its deformability! https://youtu.be/PJ2FKTHAo5s The microstructure of rolled, bent or deep-drawn workpieces is strongly deformed by the high forming forces. This...
Coarse grain annealing of a free cutting steel

Coarse-grain annealing of steel

The aim of coarse grain annealing is to improve machinability! https://youtu.be/PJ2FKTHAo5s In general a coarse-grained steel microstructure is undesirable due to the relatively low toughness and strength values. The only advantage of a...
Soft annealing

Soft annealing of steel

The aim of soft annealing is to improve formability and machinability! https://youtu.be/PJ2FKTHAo5s Not every material has to be designed to withstand high mechanical forces. With a curved sheet metal with milled out slots,...
Carburizing of a case-hardening steel

Case hardening (surface hardening)

With case hardening, low-carbon steels are first enriched with carbon in the surface layer (carburisation) and then quenched! https://youtu.be/7UcNNuqKA6U Case hardening The toughness (ductility) of steels increases with decreasing carbon content, as then less...
Diffusion annealing of a high-alloy steel

Diffusion annealing of steel

The aim of diffusion annealing is to compensate for concentration differences! https://youtu.be/PJ2FKTHAo5s When steels with high alloy concentrations solidify, the alloying elements may not be distributed homogeneously in the microstructure or in the...
Induction hardening

Induction hardening of steel (surface hardening)

With induction hardening, the workpiece is heated by induced eddy currents. The hardening depth is controlled by the frequency of the alternating current! https://youtu.be/7UcNNuqKA6U The flames during flame hardening generally lead to a...
Temperature curve during quenching and tempering

Quenching and tempering of steel

The aim of quenching and tempering is to achieve a hard and wear-resistant surface or to increase the strength of a workpiece. https://youtu.be/64qw1am8twE Introduction The heat treatments explained in the chapter on annealing processes...
Nitriding of a nitriding steel

Nitriding of steel (surface hardening)

Nitriding is not based on the formation of martensite but on the formation of hard and wear-resistant nitrides on the surface of the workpiece! https://youtu.be/7UcNNuqKA6U Surface hardening like flame hardening, induction hardening, laser...

Solution annealing of steel

The aim of solution annealing is to dissolve formed precipitates! https://youtu.be/PJ2FKTHAo5s During welding or hot forming, microstructural changes occur in the steel due to the influence of heat and uncontrolled cooling. This is...