Operation method for heat treatment of stainless steel pipe and heat-resistant steel pipe

Cleaning:

1. Oil, residual salt, paint and other foreign substances should be cleaned before thermal treatment

2. The clamping device used at the initial stage in the vacuum furnace shall be disposed of with intermittent degassing afterwards at a vacuum degree not lower than the one required by the workpiece

Furnace charging:

1. During the heat treatment process, the workpiece that is easy to be deformed should be heated on the Shared fixture intermittently

2. The workpiece should be placed in an invalid heating zone

Warm up:

1. For the workpiece with messy appearance or sharp change in section and large invalid thickness, it shall be preheated intermittently

2. How to preheat: a preheat of 800? C, 500~550? C and 850? C, the temperature rise speed of a preheating temperature should be limited

Heating:

1. The workpieces, castings and welds with notched holes, as well as the stainless steel workpieces processed and formed, are generally not suitable for heating in the salt bath furnace

2. The thermal insulation time of the workpiece should be satisfied when heating the workpiece, which can be calculated according to the invalid thickness and condition thickness of the workpiece (theoretical thickness times workpiece appearance coefficient) by referring to table 5-16 and table 5-17

Cooling:

1. Martensite stainless steel should be dispersed in a monotonous place when heat resistant steel is cooled

2. Martensite stainless steel and heat resistant steel can be quenched and cooled to room temperature before intermittent cleaning, deep-cooling treatment or tempering

3. The workpiece shall be tempered in time after quenching, and the time interval is generally not allowed to span 4h. The steel used for the workpiece has a low carbon content (carbon quality score), and the workpiece has a messy appearance and should not span 16h

4. The time interval between the welding assembly consisting of martensite stainless steel and heat resistant steel and the subsequent thermal treatment shall not span 4h