The precautions for using stamped elbows are as follows:
1. Stainless steel stamped elbows have a high degree of hardening after welding and are prone to cracking. If the same type of stainless steel stamping elbow is used for welding, preheating at 300 ℃ or above and slow cooling treatment at around 700 ℃ after welding are required.
2. Stainless steel stamping elbow coating has titanium calcium type and low hydrogen type. Titanium calcium type can be used for both AC and DC welding, but the melting depth is shallow during AC welding and it is prone to redness. Therefore, DC power supply should be used as much as possible.
3. During the welding of stainless steel stamping elbows, carbides are precipitated due to repeated heating, which reduces their corrosion resistance and mechanical properties.
4. To prevent intergranular corrosion caused by heating, the welding current should not be too high, about 20% less than that of carbon steel welding rods. The arc should not be too long, and the interlayer should be cooled quickly. Narrow weld beads are preferred.
5. When using welding rods, they should be kept dry. Titanium calcium type should be dried at 150 ℃ for 1 hour, and low hydrogen type should be dried at 200-250 ℃ for 1 hour to prevent the electrode coating from sticking to oil and other dirt, which may increase the carbon content of the weld and affect the quality of the welded part.
6. Stainless steel stamped elbows, in order to improve corrosion resistance and weldability, are appropriately added with stable elements such as Ti, Nb, Mo, etc. The weldability is better than that of stainless steel stamped elbows.
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