Differences between good and bad materials of stainless steel pipe fittings

The difference between the quality of stainless steel pipe fittings is mainly due to the different nickel content. Nickel is an excellent corrosion resistant material, which can improve the corrosion resistance and process performance of stainless steel after being mixed with chromium in stainless steel. However, in order to obtain pure austenite structure, the nickel content of low carbon nickel steel should reach 24%, and only when the nickel content is 27%, the corrosion resistance of the steel in some media can be significantly changed. The corrosion resistance of 310S stainless steel plate mainly depends on its alloy composition (chromium, nickel, titanium, silicon, aluminum, etc.) and internal structure, and chromium plays a major role.

Arc striking and end of positioned welding of stainless steel pipe fittings shall be transited smoothly. The weld bead shall not be too high, and good fusion must be ensured to prevent incomplete penetration, slag inclusion and other defects. If the tack weld is cracked, the weld at the crack must be removed and then tack welded again. After tack welding, if the interface is not flush, it shall be corrected before formal welding. Forced assembly shall be avoided as far as possible to prevent the tack weld or formal weld of weldment from cracking during welding. If necessary, the length of tack weld can be increased, and the spacing of tack weld can be reduced, or heat treatment measures can be taken. There are also many processing methods for stainless steel pipe fittings. Many also belong to the category of mechanical processing. The most commonly used methods are stamping, forging, roller processing, rolling, bulging, stretching, bending and combined processing. Pipe processing is an organic combination of machining and metal pressure processing.