Tungsten steel mould fittings work under high temperature and high pressure conditions, and their working environment is very harsh, so the manufacture of tungsten steel mould fittings needs to go through several processing and treatment. Two of the more important treatment methods are annealing and tempering. This article will focus on the analysis of these two processing methods for analysis.

First, annealing focus on analysis

1, the role of annealing

Annealing is through the heating and cooling to change the physical and chemical structure of the material, in order to achieve the desired characteristics and performance. For tungsten steel mould parts, after many times of high temperature processing, the grain becomes fine and uneven distribution, which easily leads to the increase of material brittleness and shortening of fatigue life. At this time, annealing treatment is needed to improve the grain structure and properties of the material.

2, the main points of annealing

(1) Heating temperature: the heating temperature of tungsten steel mould material is generally 1650℃-1700℃, but the specific heating temperature still needs to be adjusted according to the type, size and shape of the material and other factors.

(2) Holding time: After reaching the set heating temperature, the material needs to be fully insulated, and the holding time in the annealing room is usually 2 hours-6 hours. The longer the holding time, the more obvious changes in the grain, the material properties are more stable, but need to take into account the cost of time and energy consumption and other factors.

(3) Cooling speed: the cooling speed in the annealing process is also very important, too fast or too slow cooling will have an adverse effect on the nature of the material. Generally speaking, tungsten steel mould fittings are cooled naturally by air or slowly to avoid stress and deformation.

3、The advantages of annealing

Through annealing, the grain of tungsten steel mould fittings becomes fine and uniformly distributed, and the performance is improved, which is shown in the following aspects:

(1) Improve the ductility and toughness of the material, reduce the brittleness of the material.

(2) Reduce the internal stress and organisational defects of the material, improve the fatigue life of the material.

(3) Improve the processability of the material, improve the processing efficiency and accuracy of the mould.

Second, the focus of the analysis of tempering

1, the role of tempering

Tempering is through heating and cooling to improve the organisation and properties of steel to avoid brittleness and denaturation of steel. Unlike annealing, tempering is carried out after quenching, the purpose is to eliminate the internal stresses and brittleness produced by quenching, to restore uniformity of the organisation, improve the toughness and ductility of the material.

2, the main points of tempering

(1) tempering temperature: tempering temperature is usually lower than the quenching temperature of steel, the purpose is to eliminate internal stress and brittleness, without making the steel hardened again. In general, the tempering temperature of 500 ℃ - 700 ℃, according to the actual situation can be adjusted appropriately.

(2) Tempering time: Tempering time refers to the steel at the tempering temperature of the holding time, usually 1 hour - 2 hours or so, the time also needs to be adjusted according to the specific circumstances to ensure that the steel is fully tempered.

(3) cooling rate: the cooling rate in the tempering process is also very critical, too fast or too slow are likely to lead to steel cracking or thermal deformation. Generally speaking, tempering using slow cooling methods, so that the steel naturally cooled to room temperature.

3, the advantages of tempering

Through the tempering treatment, the organisation and properties of steel have been improved, specifically in the following aspects:

(1) Eliminate the internal stress and brittleness of steel, improve the toughness and ductility of steel.

(2) Restore the uniform organisation of the steel, improve the hardness and strength of the steel.

(3) Improve the corrosion and abrasion resistance of steel and increase its service life.

Summary:

Annealing and tempering are essential processing treatments for manufacturing tungsten steel mould parts, and they are different in terms of material properties, process flow, and operation points. By strengthening the focus on the analysis of the two treatment methods, the quality and performance of tungsten steel mould parts can be improved more effectively.