Precautions for the use of stainless steel electrodes

The use of stainless steel electrode precautions are:

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

2, chromium 13 stainless steel hardened after welding, prone to cracks. If using the same type of chromium stainless steel electrode (G202, G207) welding, preheating at 300°C or more and slow cooling at 700°C after welding must be performed. If the weldment cannot be post-weld heat treatment, a chromium-nickel stainless steel electrode (A107, A207) should be used.

3, chromium 17 stainless steel, in order to improve corrosion resistance and weldability and appropriate increase in the amount of stability elements Ti, Nb, Mo, etc., weldability better than chrome 13 stainless steel. When using the same type of chromium stainless steel electrode (G302, G307), preheating above 200°C and tempering around 800°C after welding should be performed. If the weldment cannot be heat treated, a chromium-nickel stainless steel electrode (A107, A207) should be used.

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

5, chromium-nickel stainless steel welding, subject to repeated heating precipitation of carbides, reducing corrosion resistance and mechanical properties.

6, chromium-nickel stainless steel coating titanium calcium type and low hydrogen type. Titanium-calcium type can be used for AC and DC, but the depth of penetration is shallow during AC welding and it is easy to turn red. Therefore, DC power is used as much as possible. Diameters of 4.0 and below can be used for all-position weldments, and 5.0 and above for flat and flat fillet welds.

7. When the electrode is used, it should be kept dry. The titanium-calcium type should be dried at 150°C for 1 hour. The low-hydrogen type should be dried at 200-250°C for 1 hour (can not be repeatedly dried, otherwise the coating will crack easily), preventing the electrode The skin of the skin is sticky 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 occurrence of eye erosion due to heating, the welding current should not be too large, less than 20% of carbon steel electrode, arc should not be too long, fast cooling between layers, with a narrow bead is appropriate.