Testing of Cold-drawn Steel Tube Residual Stress and Result Analysis

Analyzed is the result from testing of the cold-drawn steel tube residual stress with the hole-drilling technique.As a result, the regularities of residual stress distribution on the surface of the tube at each individual operation step of the cold-drawing process are identified.Then the result from relevant theoretic analysis is compared with that from the said testing.Based on the result from the testing of the stress distribution, the cold drawing process is optimized.And relevant method and measures for eliminating tube hazardous residual stress of the cold-drawn steel tube are proposed.It is revealed via related analysis that the steel tube as made with the equal-diameter cold-drawing process has little surface residual stress that is in any case compressive stress, and presents excellent over-all properties;adding an annealing process between two cold-drawing passes produces little effect on eliminating surface residual stress of the finished tube;and given that the total deformation is fixed, cold-drawn steel tubes with much lower surface residual stress will be produced by means of increasing the deformation of the first pass cold drawingoperation, and meanwhile reducing the deformation of the second pass cold-drawing operation.