In the welding of stainless steel rod workpiece, the choice of stainless steel welding should pay attention to the following issues:
1, chrome stainless steel has a certain corrosion resistance (oxidizing acid, organic acid, cavitation), heat and wear resistance. Usually used for power plants, chemical, oil and other equipment materials. Chromium stainless steel welding is poor, should pay attention to welding process, heat treatment conditions and the selection of appropriate welding weldings.
2, chromium 13 stainless steel after the hardening of the larger, prone to crack. If the same type of chromium stainless steel welding (G202, G207) welding, must be more than 300 ℃ preheating and 700 ℃ after the slow cooling treatment. If the weldment can not be post-weld heat treatment, you should use chrome-nickel stainless steel welding.
3, chrome 17 stainless steel, in order to improve the corrosion resistance and weldability and the appropriate increase in the amount of stability elements Ti, Nb, Mo, welding better than chrome 13 stainless steel better. When using the same type of chromium stainless steel welding (G302, G307), should be more than 200 ℃ preheating and 800 ℃ after tempering around the tempering treatment. If the weldment can not be heat treatment, you should use chrome nickel stainless steel welding.
4, chrome nickel stainless steel welding has good corrosion resistance and oxidation resistance, widely used in chemical, fertilizer, oil, medical machinery manufacturing.
5, chromium-nickel stainless steel welding, by repeated heating precipitation of carbides, reducing corrosion resistance and mechanical properties.
6, chrome-nickel stainless steel skin with titanium and low hydrogen type. Titanium calcium type can be used for AC and DC, but the depth of soldering when welding deep, and easy to red, so as far as possible the use of DC power supply. Diameter 4.0 and below can be used for all-position welding, 5.0 and above for flat welding and flat welding.
7, the welding should be used to dry, titanium calcium type should be dried at 150 ℃ for 1 hour, low hydrogen type should be 200-250 ℃ drying 1 hour (can not be repeated drying, or easy to peel the skin peel), to prevent the welding Skin sticky oil and other dirt, so as not to cause the weld to increase the carbon content and affect the quality of welding.
8, in order to prevent the heating caused by the eye between the corrosion, welding current should not be too much, less than about 20% of carbon steel welding, arc should not be too long, cold between the layers, narrow bead is appropriate.