Classification of surface heat treatment

Surface heat treatment technology can be roughly divided into three categories: overall surface heat treatment, surface heat treatment and chemical surface heat treatment. The same metal chooses different surface heat treatment technology, which can achieve different arrangements, and then has different functions. Let's analyze the specific problem specifically to see what three methods of surface heat treatment are:

First, the overall surface heat treatment

1. Annealing is to heat the workpiece to the appropriate temperature, select different insulation moments according to the data and workpiece scale, and then slowly cool, the intention is to make the metal internal arrangement reach or close to the equilibrium condition, obtain outstanding technical functions and application functions, perhaps for further quenching to make arrangements.

2, normalizing is to heat the workpiece to a suitable temperature after cooling in the air, the role of normalizing is similar to annealing, only the arrangement obtained is more fine, often used to improve the cutting function of the data, and sometimes used for some parts with low demand as the end surface heat treatment.

3. Quenching is to heat and keep the workpiece warm, and then quickly cool it in a quenching medium such as water, oil or other inorganic salts and organic aqueous solutions. After quenching, the steel parts harden, but together they become brittle.

4. In order to reduce the brittleness of the steel, the quenched steel is insulated for a long time at an appropriate temperature higher than the room temperature and below 650 °C, and then cooled, this technology is called tempering Second, surface heat treatment

Surface heat treatment is a metal surface heat treatment technology that only heats the surface layer of the workpiece to change its surface mechanical function. In order to only heat the surface of the workpiece without too much heat into the workpiece, the heat source used must have a high energy density, that is, a large amount of heat energy is given to the workpiece per unit area, so that the surface or part of the workpiece can reach high temperature for a short time or instantaneously. The primary methods of surface heat treatment are flame quenching and induction heating surface heat treatment, and commonly used heat sources are flames such as aerobic acetylene or propane-oxy, induced current, laser and electron beam.

3. Chemical surface heat treatment

Chemical surface heat treatment is a metal surface heat treatment technology that changes the chemical composition, arrangement and function of the surface of the workpiece. Chemical surface heat treatment differs from surface heat treatment in that it changes the chemical composition of the workpiece surface. Chemical surface heat treatment is to heat the workpiece in a medium (gas, liquid, solid) containing carbon, nitrogen or other alloying elements, keep it warm for a long time, and then make the surface of the workpiece enter the elements such as carbon, nitrogen, boron and chromium. Once in the elements, other surface heat treatment techniques such as quenching and tempering are sometimes required. The primary methods of chemical surface heat treatment are carburizing, nitriding and metal imposition.

The development of science and technology, forcing all walks of life to develop rapidly, the steel industry application of surface heat treatment is also more and more, different surface heat treatment methods, the production of processing parts are also different, only to understand what kind of treatment, can be more conducive to their work.