On 2018-08-08 14:48:54
Heat treatment process of aluminum alloy casting
Heat treatment process, heating, heat preservation, quenching and aging of aluminum alloy castings
1、 Preparation before heat treatment (equipment: aluminum alloy solid solution (quenching) furnace)
1. Before heat treatment, check whether the heat treatment equipment, control system and instruments are normal.
2. Castings shall be dry and free of oil contamination, dirt and explosion before charging. Castings treated shall be classified according to alloy brand, outline size, wall thickness of castings and heat treatment specification. Different brand shall not be mixed for charging.
3. Castings easy to warp shall be placed on a special chassis or bracket, and cantilever parts are not allowed to be suspended. Large castings shall be installed on a special frame.
4. The single cast or auxiliary cast test bar for checking the casting performance shall be heat treated together with the parts in the same furnace to determine the performance reflecting the casting.
2、 Heating and heat preservation
1. After heating to the set temperature, check and correct the temperature of all parts of the furnace (± 5 ℃) at any time during the heat preservation period to prevent local high temperature or burning.
2. If it can't be recovered in a short time after power failure, the castings in the heat preservation shall be put out of the furnace for quenching quickly. After the castings return to normal, they shall be charged, heat preservation and heat treatment, and the total heat preservation time shall be slightly extended.
3、 Cooling out:
1. After the heat preservation, open the furnace door and put down the material basket to quickly drop the casting into the water pool and quench it into the specified cooling medium for cooling.
2. Quenching transfer time refers to the total time from the time when the casting is discharged to the time when the casting is all quenched into the medium, which should not exceed 15s.
3、 Correction of casting deformation:
1. The casting deformation shall be corrected immediately after quenching, and the straightening mould and tools shall be prepared before quenching.
2. According to the characteristics and deformation of the casting, the corresponding correction method shall be selected. The force shall not be too strong during correction, and it shall be slow and uniform.
4、 Aging operation: (equipment: aluminum alloy aging furnace)
1. Castings requiring artificial aging shall be aged within 0.5h as soon as possible after quenching. The quenched material basket can be pushed directly into the aging furnace, but the product temperature shall not exceed the aging temperature.
2. Set the temperature of the automatic temperature control instrument, then send electricity to heat it, and turn on the fan.
3. When the holding time is up, disconnect the power supply.