Reasons For The Decline In The Quality Of Bent Pipes And How To Pay Attention To Them

During pure bending, the outer arm wall of the neutral layer of the Stainless Steel Weld Elbow is thinned by the tensile stress &1 under the action of the external force distance M, and the inner side is subjected to compressive stress. The resultant forces N1 and N2 cause the cross-section of the tube to change. Based on this factor, the main reasons for the decline in the quality of bent pipes are RX and SX. Therefore, GBJ235-82 clearly stipulates the RX value under various pressure levels and the amount of thinning on the outside, in order to control RX with SX values, thereby ensuring quality.

When bending the pipe, the outside of the material is under tension and the inside is under pressure. The location of the neutral axis is different from the pipe bending method. When working in top bending (compression bending), the neutral axis is located about 1/3 away from the outer wall. In rotation bending ( When working (return type), the neutral axis is located 2/3 away from the outer wall. Therefore, it is beneficial to use the spiral bending method for thin-walled pipe bending.