Reminder: Eight matters that should be paid attention to when using stainless steel electrodes

1. Chromium stainless steel has certain corrosion resistance (oxidizing acid, organic acid, cavitation), heat resistance and wear resistance. Usually used for power station, chemical, petroleum and other equipment materials. The weldability of chromium stainless steel is poor, so attention should be paid to the welding process, heat treatment conditions and the selection of suitable welding rods.

2, Chromium 13 stainless steel has greater hardenability after welding and is prone to cracks. If the same type of chromium stainless steel electrode (G202, G207) is used for welding, preheating above 300°C and slow cooling treatment at about 700°C after welding must be carried out. If the weldment cannot be subjected to post-weld heat treatment, chromium-nickel stainless steel electrodes (A107, A207) should be used.

3. In order to improve the corrosion resistance and weldability of chromium 17 stainless steel, appropriate amount of stability elements Ti, Nb, Mo, etc. are added appropriately, and the weldability is better than that of chromium 13 stainless steel. When using the same type of chromium stainless steel electrode (G302, G307), it should be preheated above 200°C and tempered at about 800°C after welding. If the weldment cannot be heat treated, chromium-nickel stainless steel electrodes (A107, A207) should be used.

4. Chromium-nickel stainless steel electrodes have good corrosion resistance and oxidation resistance, and are widely used in chemical, fertilizer, petroleum, and medical machinery manufacturing.

5. When chromium-nickel stainless steel is welded, carbides are precipitated after repeated heating, which reduces corrosion resistance and mechanical properties.

6. The chromium-nickel stainless steel coating 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 AC welding, and it is easy to redness at the same time, so use DC power as much as possible. 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.

7. The electrode should be kept dry when using it. The calcium-titanium type should be dried at 150°C for 1 hour, and the low-hydrogen type should be dried at 200-250°C for 1 hour. , To prevent the electrode coating from sticking to oil and other dirt, so as not to increase the carbon content of the weld and affect the quality of the weldment.

8. In order to prevent the corrosion between the eyes due to heating, the welding current should not be too large, about 20% less than carbon steel electrode, the arc should not be too long, the interlayer cooling is fast, and the narrow welding bead is better.