Steel elbows formed by hot pressing or forging processes are stainless steel elbows. Stainless steel elbows are welded to steel pipes by butt welding. The two workpieces are welded together along the entire end face through resistance heating. There are usually two methods of resistance butt welding and flash butt welding. They have high productivity and are easy to achieve automation, so they have been widely used.
Stainless steel elbows not only save space and reduce weight, but also ensure that the joint does not leak and has good sealing performance. Stainless steel elbows also have corrosion resistance (oxidizing acids, organic acids, cavitation), heat resistance and wear resistance. They are usually used in power stations, chemical, petroleum and other industries. The weldability of stainless steel pressed elbows is poor. Attention should be paid to the welding process, the prerequisites of heat treatment and the selection of appropriate electrodes.
Stainless steel elbows are widely used. Generally, they are made by rolling common carbon structural steel, low alloy structural steel or alloy structural steel. They have a large output and are mainly used as pipelines or structural components for fluid transportation. When using ball valves, globe valves and gate valves with stainless steel elbows, they are not allowed to be used for flow regulation and can only be fully open or fully closed to avoid corrosion of the sealing surface and accelerated wear. The gate valve and threaded stop valve are equipped with reverse sealing devices inside. The handwheel should be turned to the upper position and tightened to prevent the medium from leaking from the packing.
The factors affecting the polishing performance of stainless steel elbows include surface defects of raw materials (scratches, pockmarks, pickling), and after deep drawing, small black spots will appear on the surface of the large deformation zone, which will have an impactBQThe performance of the material, the material issue of the raw materials, the hardness is too low, it is not easy to polish, the hardness is too low, and the surface is prone to orange peel during deep drawing, which affectsBQHigh performance and hardnessBQBetter.
Most stainless steel elbow fittings are used for welding. To improve the welding quality, grooves with certain angles and edges are opened at both ends. This requirement is also very strict. The thickness, Angle and deviation range of the edges are all specified. The geometric dimensions are much more than those of pipe fittings. The surface quality and mechanical properties of the elbow are basically the same as those of the pipe. To facilitate welding, the steel of the pipe to be connected should be the same. Stainless steel elbows can resist the erosion of various chemical media except for a few hydrogenation agents. They have excellent acid and alkali resistance, corrosion resistance, do not rust, do not corrode, do not breed bacteria, and do not undergo electrochemical corrosion.
Stainless steel elbows that have been stored for a long time should be inspected regularly. The exposed processed surfaces should always be kept clean, dirt removed, and neatly stored in a well-ventilated and dry indoor place. Stacking or open-air storage is strictly prohibited. The stainless steel elbows should always be kept dry and well-ventilated, and the protective rings should be kept clean and tidy. They should also be stored in accordance with the correct storage methods.
