Cleaning:

1. Workpieces and fixtures should be removed before the heat treatment of oil, residual salt, paint and other foreign objects

2. The fixture used for the first time in a vacuum furnace shall be subjected to a degassing process in advance at a temperature not lower than the vacuum required by the workpiece

Furnace:

1. In the heat treatment process easy to deform the workpiece, should be heated on a special fixture

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

Preheat:

1. For the shape of the complex or cross-section has a sharp change in the effective thickness of the workpiece should be preheated

2. Warm-up methods are: a preheat to 800? C, the second preheat of 500 ~ 550? C and 850? C, a preheating temperature should be limited

heating:

1. The workpiece, the casting and the welded parts and the machined stainless steel workpieces which are not through the holes are generally not suitable for heating in the salt bath

2. Workpiece heating should have sufficient holding time, according to the workpiece effective thickness and condition thickness (actual thickness multiplied by the workpiece shape factor) refer to Table 5-16 and Table 5-17 to calculate