In the quenching process of stainless steel pipe fittings of defects

In the process of heat treatment of stainless steel pipe fittings, one not careful, stainless steel pipe fittings often appear some defects, thus affecting the quality of the products of heat treatment, appear even scrapped, so must take effective measures to prevent, and to have defects, should be set to save, the emphasis on analysis of common defects in stainless steel pipe fittings quenching process, and make the corresponding preventive and remedial measures.

Defect: overheating and burnt
Reason: the heating temperature is too high or the heating time is too long
Preventive and remedial measures:
1. Correct selection of quenching heating temperature and heating time
2. The contralateral thermometer temperature scale calibrated regularly, prevent instrument malfunction and overtemperature
3. Reasonable furnace charging, prevent the workpiece and the heating body too close
Defect: quenching distortion
The reason:
1. Stainless steel casting workpiece shape asymmetry or thickness disparity
2. The machining stress is big, did not eliminate before quenching
3. Uneven heating and cooling
4. Heating of workpiece clamping methods and improper cooling
5. Quenching organization transformation
Preventive and remedial measures:
1. Improve the workpiece structure, reasonable material selection, adjust the machining allowance, etc
2. Increasing preheat or to stress annealing process, reasonable heat treatment
3. Several times with preheating, precooling quenching and grade of double liquid quenching, quenching isothermal quenching and so on a variety of operating methods
4. Correct operation and reasonable support bundle, scattered cooling quenching heating workpiece
5. School was carried out on the deformation of the workpiece.

Stainless steel welded pipe in overheating for 1 to 2 times after normalizing or annealing of fine grains, annealing, according to the normal process again across burning stain-less steel scrap processing.

Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)