Stainless steel elbows should pay attention to the sealing during installation to prevent leakage and affect the normal operation of the pipeline. Under normal circumstances, it can be installed at any position of the pipeline, but it is necessary to facilitate the inspection of the operation. Note that the flow direction of the stainless steel elbow medium should be upward and downward from the longitudinal valve. The stainless steel elbow can only be installed horizontally. When the ball valve of the stainless steel elbow, the stop valve and the gate valve are used, they are only fully open or fully closed, and do not allow to adjust the flow rate, so as to avoid erosion of the sealing surface and accelerate wear. The gate valve and the upper thread stop valve have an inverted sealing device, and the hand wheel is rotated to the highest position to the user.
The difference between the stainless steel elbow and the carbon steel elbow is mainly due to the difference in material. The chemical composition of the elbow will keep the elbow in the actual use and produce important performance and operational value. There are many things to be aware of when using and maintaining stainless steel elbows. Users need to use them according to certain methods and use and maintain them in an accurate and fair manner. When the stainless steel elbow is installed, the stainless steel elbow can be directly connected to the pipeline according to the connection, and installed according to the position used. Stainless steel elbows play an important role and value in installation and use, and produce good operation in certain environments and media.
The electrode used for stainless steel elbow should be kept dry when used. The titanium calcium type should be dried at 150 °C for 1 hour, and the low hydrogen type should be dried at 200-250 °C for 1 hour (do not repeat drying repeatedly, otherwise it is easy to crack and peel off) to prevent The electrode is viscous oil and other dirt to prevent the weld from increasing the carbon content and affecting the quality of the weldment. When the stainless steel elbow is welded, it is repeatedly heated to precipitate carbides, which reduces corrosion resistance and mechanical properties. The post-weld hardenability is large and cracks are likely to occur. If welding of the same type of welding rod is used, preheating at 300 °C or higher and slow cooling at around 700 °C after welding must be performed. If the weldment cannot be post-weld heat treated, a chrome-nickel stainless steel electrode should be used.
The most basic difference between stainless steel elbows and elbows is that stainless steel elbows are relatively short compared to elbows. R = 1 to 2 times is the elbow, and the larger multiple is called the elbow. In the production process, the cold-bent pipe can be bent with a ready-made straight pipe bending machine, and the secondary completion does not require secondary corrosion protection. But the elbow should be customized by the manufacturer, to be anti-corrosion, and the ordering period is long. The price of the elbow is higher than that of the elbow, but the cost performance is much higher than that of the elbow. It is well known that the elbow without the anticorrosion treatment is easily damaged, but it is used in many projects that are not very demanding because of the low price.
The cold bend pipe can be bent with a ready-made straight pipe bender. The stainless steel elbow is not finished with a secondary anti-corrosion. The cold-bending pipe construction process has an oil standard, and the West-East Gas Pipeline has an enterprise standard. However, the elbows in the open areas can be bent. Only the cost is considered. The elbows need to be hot, and the elbows can be cold-bent. Of course, the elbows are expensive. Sometimes elbows must be used in narrow sections, such as stone section trenches, because the radius of curvature of the elbow is small, generally 6D, and the elbow is 40D. In fact, the most intuitive view (pure personal opinion) is that the elbow is equivalent to the overall caliber, and the elbow is much slender.