Steel pipe processing methods

Steel pipe processing and furnace installation:
1. Workpieces that are easily deformed during heat treatment should be heated on a special fixture.
2. The workpiece should be placed in the effective heating zone
Warm-up:
1. For workpieces with complex shapes or sharp changes in cross-section and large effective thickness, preheating should be stopped.
2. Preheating methods include: primary preheating is 800°C, secondary preheating is 500~550°C and 850°C. The temperature rise speed of primary preheating should be limited.
heating:
1. Workpieces with grooves and closed holes, castings and weldments, as well as processed stainless steel workpieces, are generally not suitable for heating in a salt bath furnace.
2. There should be sufficient holding time for heating the workpiece, which can be based on the effective thickness of the workpiece and the conditional thickness (actual thickness multiplied by the workpiece shape coefficient)
Cool down:
1. When martensitic stainless steel heat-resistant steel is air-cooled, it should be scattered in a dry place
2. Steel pipes of martensitic stainless steel and heat-resistant steel can be cleaned, cryogenically treated, or tempered before being quenched to room temperature.
3. The workpiece should be tempered in time after quenching. The time interval should generally not exceed 4 hours. The carbon content (mass fraction of carbon) of the steel used in the workpiece is low and the shape of the workpiece is simple. The time interval should not exceed 16 hours.
4. For welded assemblies composed of martensitic stainless steel and heat-resistant steel, the time interval between welding and subsequent heat treatment should not exceed 4 hours.
Liquidation:
1. According to the requirements and surface conditions of the workpiece, use alkali cleaning, water-soluble cleaning agents, chlorine solvent sandblasting, shot blasting, and other cleaning methods.
2. Pickling is generally not used for cleaning.