How to improve the hardness of light - burnt magnesium ball

Magnesium ball can be improved by heat treatment strength and hardness, the following provides various heat treatment effects, light burning magnesium ball you can choose the appropriate heat treatment according to the situation. Surface quenching is recommended if only to increase hardness. The purpose of nodular iron normalizing is to obtain pearlite matrix structure, and refine grain, uniform structure, in order to improve the mechanical properties of castings. Lightly burn magnesium balls

Sometimes normalizing is also the preparation of ductile iron surface quenching in the organization, normalizing high temperature normalizing and low temperature normalizing. The high temperature normalizing temperature is generally not more than 950 ~ 980℃, and the low temperature normalizing temperature is generally heated to the co-folding temperature range of 820 ~ 860℃. After normalizing, it is generally necessary to deal with four people in order to eliminate the internal stress generated when normalizing.

In order to improve the mechanical properties of ductile iron, castings are generally heated to 30 ~ 50℃ above Afc1 (Afc1 represents the final temperature formed by A during heating), and then quenched into oil to obtain martensite structure after heat preservation. In order to properly reduce the residual stress after quenching, the general quenching should be tempered, low temperature tempering structure is tempered martensite plus residual bainite and spherical graphite. This kind of structure has good wear resistance and is used for parts requiring high wear resistance and high strength. Medium temperature tempering temperature of 350-500 ℃ after tempering structure is tempered trostenite plus spherical graphite, suitable for the requirements of good wear resistance, stability and elasticity of the thick parts. The high-temperature tempering temperature is 500-60D ℃, and the tempered structure is tempered Soxhlet for spherical graphite, which has a good combination of toughness and strength, so it is widely used in production.

Ductile iron can obtain high strength and good plasticity and toughness after isothermal quenching. The selection of heating temperature for multi-temperature quenching is mainly to make the original structure all A, no residual F, but also to avoid the growth of A grain. The heating temperature is generally 30 ~ 50℃ above Afc1, and the isothermal treatment temperature is 0 ~ 350℃ to ensure the lower bainite structure with comprehensive mechanical properties. After isothermal quenching, σb=1200 ~ 1400MPa, αk=3 ~ 3.6J/cm2, HRC = 47 ~ 51. But attention should be paid to adding a tempering process after isothermal quenching.