Steel Pipe Processing and Furnace Loading:
1. During the heat treatment process, workpieces that are easily deformed should be heated on a special fixture
2. The workpiece should be placed in the effective heating zone
Preheating:
1. For workpieces with complex shapes or sharp changes in cross-section and large effective thickness, preheating should be stopped
2. The preheating methods are: primary preheating is 800oC, secondary preheating is 500~550oC and 850oC, and the primary preheating temperature rise rate should be limited
Heating:
1. Workpieces with grooves and non-through holes, castings and welded parts, and processed stainless steel workpieces are generally not suitable for heating in a salt bath furnace
2. The workpiece should be heated for a sufficient insulation time, which can be referenced according to the effective thickness and conditional thickness of the workpiece (practical thickness multiplied by the workpiece shape coefficient) Tables 5-16 and Table 5-17 are used for calculation
Cooling:
1. When martensitic stainless steel and heat-resistant steel are air-cooled, they should be scattered in a dry place
2. Before the martensitic stainless steel and heat-resistant steel of steel pipes are quenched and cooled to room temperature, they can be cleaned, cryogenically treated, or tempered
3. The workpiece should be tempered in time after quenching. The time interval should not exceed 4h. The carbon content (mass fraction of carbon) of the steel used for the workpiece is low, and the workpiece shape is simple. It should not exceed 16h
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 4h
Cleaning:
1. According to the requirements and surface conditions of the workpiece, alkaline cleaning, water-soluble cleaning agent, chlorine solvent sandblasting, shot blasting and other methods are used for cleaning
2. Generally, pickling is not used for cleaning
Post time: Aug-27-2024