1, The excessive hardness problems for elbow, mainly due to forming heat treatment process problems, the solution is to use the correct heat treatment process and then a heat treatment.
2, materials and processing defects arising. Defective factors are more and more complex, it has both the material itself defects and manufacturing process problems and heat treatment process caused by the defects of the incorrect. glenflange
3, uneven pipe wall thickness occurs mainly in the deformation of the largest parts of the pipe, such as elbow back wall thickness is thinner than other parts; nozzle and pipe body wall thickness. According to the relevant national standards, inspection of such problems is often difficult to find with measuring tools such as calipers, and only the use of ultrasonic gages can be measured.