Avoid Spiral Steel Tube Rupture in Long Pipeline

Currently, the project is widely used annealed after welding cooling to eliminate residual stress, while cooling after welding residual stress is an important process, this approach is not a waste of energy and easy to produce larger welding residual stresses. Post weld heat treatment is a new technique to eliminate residual stress. After the material is preheated before welding to heat treatment temperature and the welding process to maintain continuous heating of the weld member that temperature after soldering using its thermal insulation cotton allowed to cool slowly. This method can effectively reduce the welding residual stress, improve resistance to stress corrosion of metals. Post weld heat treatment can effectively reduce the welding residual stress, and heat treatment temperature is higher, the residual stress better. After the heat treatment can be effectively improved resistance to stress corrosion spiral welded steel pipe, the higher the heat treatment temperature, stress corrosion resistance increased more significant. Pipeline Industry Development of China's second climax will surely come. Spiral steel pipe (ssaw steel pipe) will be put into research, and enhance the pipeline capacity. Improve and increase the diameter of the intensity level, due to the importance of the people's lack of understanding of the impact toughness of the material, in many parts of the world have occurred fragility and fracture toughness of pipeline accidents. Through the analysis of these incidents, research, and "fracture mechanics" as the development of a new discipline and practical application in the pipeline industry, increasing the awareness of the importance of understanding the impact toughness of the pipe. Toughness index has actually become a pipe line pipe important indicator. In fact, the spiral steel pipeline transportation has many advantages, is the resilience of poor transmission capacity shortage. For just freezing point, high waxy crude oil, higher than the designed capacity, the pipeline will be constrained by existing capacity and pressure pumping capacity; below the designed capacity, the pipeline will be constrained by existing thermal conditions. To overcome this fixed point, only with the DRA and depressant. Spiral steel pipe and ductile crack extension instability instability expansion. How to avoid pipeline breaks have a way of base metal and weld flattening test, guided bend test, a number of indicators of landing inspection toughness test, Charpy impact test. Not only for the gas pipeline has a higher toughness requirements for oil pipelines in recent years also made a high impact toughness requirements. For long-distance pipeline, it should completely avoid crack initiation is very difficult, in fact, at home and abroad are difficult to fully achieve. This is because the long-distance pipeline hundreds of kilometers long and some even more than a thousand kilometers long welds, weld too much, plus the damage caused during construction and transportation, etc., so that increases the chances floor room. Currently, the project is widely used to eliminate residual stress annealed after welding cooling, and cooling after welding residual stress is an important process, this approach is not a waste of energy and easy to produce larger welding residual stresses. Post weld heat treatment is a new technique to eliminate residual stress. After the material is preheated before welding to heat treatment temperature and the welding process to maintain continuous heating of the weld member that temperature after soldering using its thermal insulation cotton allowed to cool slowly. This method can effectively reduce the welding residual stress, improve resistance to stress corrosion of metals. Post weld heat treatment can effectively reduce the welding residual stress, and heat treatment temperature is higher, the residual stress better. After the heat treatment can be effectively improved resistance to stress corrosion spiral welded steel pipe, the higher the heat treatment temperature, stress corrosion resistance increased more significant. Pipeline Industry Development of China's second climax will surely come. Spiral steel pipe will be put into research, and enhance the pipeline capacity.