1. The welding rod should be combined with drying. The titanium-calcium type should be dried at 150℃ for 1 hour, and the low-hydrogen type should be dried at 200-250℃ for 1 hour. The drying should not be repeated, otherwise the coating will easily crack and peel to prevent the coating of the electrode. Sticky oil and other dirt can prevent or even increase the carbon content of the weld and affect the quality of the weldment. The weldability of stainless steel flanges is poor, and attention should be paid to the welding process, heat treatment conditions and the selection of suitable welding rods.
2. The chromium stainless steel pipe fittings are stronger after welding and are easy to crack. If the same type of chromium stainless steel electrode is used for welding, preheating above 300℃ and slow cooling at 700℃ after welding must be carried out. If the weldment cannot be subjected to post-weld heat treatment, stainless steel flange pipe welding rods should be used.
3. In order to improve the corrosion resistance and weldability of stainless steel pipe fittings, appropriate strengthening elements such as Ti, Nb, Mo, etc. are appropriately increased. The weldability is less than that of chromium stainless steel flanges. When using the same type of chromium stainless steel electrode, preheating above 200℃ and tempering treatment at 800℃ after welding should be carried out. If the weldment cannot be heat treated, stainless steel flange pipe welding rods should be used.
4. Welding rods for stainless steel pipe fittings have good corrosion resistance and oxidation resistance, and are widely used in the manufacture of chemicals, fertilizers, kerosene, and medical machinery.
5. When stainless steel pipe fittings are welded, carbides are precipitated after repeated heating, which reduces corrosion resistance and mechanical properties.
6. The coating of stainless steel pipe fittings has titanium calcium type and low hydrogen type. Titanium-calcium type can be used for AC and DC, but the penetration depth is relatively shallow during exchange welding, and it is prone to redness, so it is best to use DC power. Diameter 4.0 and below can be used for all-position weldments, and 5.0 and above are used for flat welding and flat fillet welding.
