Problemsolutions: Quenching

Beside the structure and the surface-quality also the appearence of the surface of heat treated components is an important feature for outstanding product-quality.

REQUIRED LIGHT AND MIDDLE –GREY SURFACES AT CARBURIZED COMPONENTS

PROBLEM:

components of material 16MnCr5 have been quenched after carburizing in a pusher-furnace in oil.The surface-colour of the components have been in the range of yellow-bluish and partly brown. Analysing the surface of the components have confirmed that the discolouration have been caused by oxygen.

SOLUTION:

the quenching chamber was split by a separate wall in two parts. The part of the quenching chamber, which was connected directly with the furnace was under protective gas. The other part (exit) had direct contact with the atmosphere (oxygen). Through strong circulation of the oil-fans oxygen has been introduced in the quench-oil. The quenching chamber has been modified in this way, that the wall has been taken away and at the oil-bath exit a gas-tight door has been installed by which the whole oil-bath was under protective atmosphere.

ADVANTAGES:

it was now not anymore possible to mix the quenching oil with air, the oxidation of the components could be avoided. All components left the furnace with bright surfaces.

Author: Beitz