What should notice when welding stainless steel pipe fittings?
Stainless steel fittings manufacturer china introduce you: 1, due to the heating to guard against erosion between eyes, welding current shoulds not be too eve, 20% less than carbon Steel electrode mercy, arc shoulds not be too long, interlayer cold quickly, with narrow bead advisable.
2, stainless steel pipe fittings after welding hardenability is relatively large, easy to crack.If the acceptance of typical stainless steel pipe welding, it is necessary to preheat more than 300℃ and after welding 700℃ around the cooling disposal.If the welding can not be hot disposal after welding, should choose stainless steel pipe welding rod.
3, stainless steel pipe fittings, in order to improve corrosion resistance and weldability and appropriate amount of invariable elements Ti, Nb, Mo, etc., better weldability than stainless steel pipe fittings.When accepting the typical chromium stainless steel electrode, it should be preheated above 200℃ and tempered at 800℃ after welding.If the welds cannot be disposed of thermally, chrome-nickel stainless steel electrode shall be used.
4, stainless steel cast fittings with elaborate erosion resistance and oxidation resistance, widely used in chemical, fertilizer, oil, medicine, machinery manufacturing.
5. Stainless steel pipe fittings have titanium calcium type and low hydrogen type.Titanium-calcium type can be used for ac and dc, but ac welding when the melting depth is relatively shallow, at the same time convenient reddiness, so all roughly accept dc power supply.
6, Stainless steel pipe fittings china has must be corrosion resistant (oxidizing acid, organic acids, cavitation), heat-resisting and wear-resisting function.Generally used in power stations, chemical, petroleum and other equipment equipment materials.Stainless steel pipe welding is poor, should pay attention to the welding process, thermal treatment before the selection of appropriate electrode.
7, the operation of the electrode should be connected to dry, titanium calcium type should be dried by 150℃ for 1 hour, low hydrogen type should be dried by 200-250℃ for 1 hour (can not be repeatedly dried, otherwise the coating is convenient to crack off), beware of the electrode coating oil and other dirt, so as not to add carbon to the weld and affect the quality of the welding.
8. During welding of stainless steel pipe fittings, carbide is precipitated by repeated heating, which reduces corrosion resistance and mechanical function.
Common problems mainly include the following, specifically:
1. Uneven wall thickness of sanitary stainless steel pipe fittings
The uneven wall thickness of sanitary stainless steel pipe fittings mainly occurs in the parts with the largest deformation of stainless steel pipe fittings, such as the wall thickness on the back of elbow is thinner than other parts;The wall thickness of the nozzle and the stainless steel fitting body is different.To detect these problems, calipers and other commonly used measuring tools are not easy to detect, at this point only the use of ultrasonic thickness gauge can be detected.
2. Excessive hardness
The problem of excessive hardness is mainly caused by the heat treatment process after forming. The solution is to conduct another heat treatment with the correct heat treatment process.
3. Inspection of stainless steel pipe fittings before and after delivery
As the last step to ensure the quality of sanitary stainless steel pipe fittings, inspection plays an important role, especially for the stainless steel pipe fittings under high temperature and pressure and flammable and highly toxic medium, the inspection process is particularly important.
Stainless Steel Pipe Fittings