There are a lot of precision casting investment casting carbon steel heat treatment. For example, the whole cast annealing, normalizing and normalizing plus tempering. For particularly large precision castings, mostly using the diffusion annealing heat treatment methods.
1. What is the full annealed casting.
The casting is heated to the austenite region temperature range and kept for some time, and then cooling with the furnace annealing method taught full, abbreviated annealing.
Upon heating, the guarantee does not produce the casting deformation and cracking under the premise. Win rapid heating, a set to increase production capacity. Heating rate depends on the chemical composition of the steel. Shape of a small cross-section castings and castings. Contains a high amount of carbon steel. Poor thermal conductivity, the heating rate is low allowable. Shoulders of the larger cross-section. The greater the temperature difference between the inner layer upon heating, due to the greater thermal stress, so the heating rate more slowly. Complex shape, section thickness of casting a big difference, the heating rate should be slower.
2, the normalizing heat treatment.
Normalizing heating temperature and holding time and full-annealing the same, the difference is reached after the holding time, speaking casting is cooled to room temperature in air.
3. Casting normalized and tempered
In order to improve the structural performance just can adopt them after tempering normalizing heat treatment process. Tempering temperature of 500-650 degrees, are tempering, heat To 2-3 hours,
4, carburizing
Lost wax casting surface decarburization phenomenon, is a more serious flaw. The carbon content of the surface layer of decarbonization will just be reduced. For medium and high carbon steel is more obvious.
Heat treatment significantly increased the precision machinery casting properties. All products are casting a lot of companies do heat treatment. But the heat treatment process more complicated.
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