Aluminum plate workpieces and fixtures shall be removed from oil stains, residual salt, paint and other foreign substances before heat treatment.
The fixture used for the first time in the vacuum furnace shall be degassed and purified in advance at a vacuum level not lower than that required by the workpiece. The furnace shall be installed: 1.
Aluminum plate is easy to deform during heat treatment, and should be heated on a special fixture 2.
The workpiece shall be placed in the effective heating zone for preheating: 1.
For workpieces with complex shapes or sharp changes in cross sections and large effective thickness, preheating shall be carried out.
Preheating methods include: one preheating is 800 ℃, and the second preheating is 500 ~ 550 ℃ and 850 ℃, the temperature speed of one preheating rise should be limited, heating: 1.
Workpieces, castings and welded parts with grooved through holes, and aluminum plate workpieces processed and formed are generally not suitable for heating in salt bath furnaces.
The workpiece heating should have sufficient holding time, which can be based on the effective thickness of the workpiece and the condition thickness (Actual thickness multiplied by workpiece shape coefficient)Cooling: 1.
When the aluminum plate is air cooled, it should be scattered in a dry place.
Martensitic stainless steel diamond plate and heat resistant steel can be cleaned, cryogenic treated or tempered only after quenching to room temperature.
The aluminum plate shall be tempered in time after quenching, and the time interval shall not exceed 4h in general. The carbon content of the steel used for the workpiece (Mass fraction of carbon)
Lower, the shape of the workpiece is simple and should not exceed 16h 4.
For welding assemblies composed of aluminum plates, the time interval between welding and subsequent heat treatment shall not exceed 4h for cleaning: 1.
According to the requirements of the workpiece and the surface condition, alkaline washing, water-soluble cleaning agent, chlorine solvent sandblasting, shot peening and other methods are used for cleaning.
Generally, pickling is not used for cleaning. Correction: 1.
The workpiece is corrected by static load, and it is generally not suitable for local tapping 2.
After correction, stress relief annealing shall be carried out at a temperature lower than the original tempering temperature.
The workpiece with complex shape or strict size requirements shall be corrected by setting fixture combined with tempering after correction.
The aluminum plate workpiece shall be subjected to stress relief treatment quality inspection below 300 ℃ after correction: 1.
The workpiece shall be inspected according to the items and requirements specified in the corresponding technical documents.
When the mechanical properties of the workpiece are unqualified, heat treatment can be repeated, but the number of repeated quenching or solid solution is generally not more than two times.
Supplementary tempering of workpieces is not counted as repeated treatment 3.
Martensite stainless steel diamond plate and heat resistant steel workpiece in quenched state or tempered at low temperature shall be preheated, annealed or tempered at high temperature before repeated quenching.
The original records of heat treatment shall be properly kept for future reference. Safety Technology: when heat treatment of workpieces, JB4406-87 relevant provisions of heat treatment safety technology