Aging treatment refers to the heat treatment process of metal or alloy workpieces (such as low carbon steel) after solution treatment, from high-temperature quenching or a certain degree of cold working deformation, at a higher temperature or room temperature to maintain their shape and size, and their properties change with time.
QPQ is an abbreviation for “Quench—Polish-Quench”. A more accurate description is called “salt bath composite treatment technology”.
Nitriding treatment refers to a chemical heat treatment process in which nitrogen atoms penetrate the surface of the workpiece in a certain medium at a certain temperature.
After holding for enough time, the decomposed active carbon atoms in the carburizing medium are infiltrated into the surface of the steel piece, and thus high carbon was obtained in the surface layer and the original composition was maintained in the heart.
The difference between salt bath and other heat treatment methods is that when the workpiece is heated, it is immersed in melted inorganic salt.
The workpiece is placed in an inductor made by spiral hollow copper tubes. The inductive current is formed on the workpiece surface after the copper tubes fed with medium or high-frequency AC.
To reduce the brittleness of steel parts, the quenched steel parts are kept warm for a long time at a suitable temperature higher than room temperature but lower than 710 C° and then cooled.