The Expansion And Applition Of X-Ray Test Stress System

The following extensions of possession for stress testing instrument, based on X-ray diffraction theory, are achieved by building corresponding software of new testing method, according to the X-ray testing theoretical basis of polycrystalline materials stress obtained by Bragg equation derivation: 1) The real-time observation of diffraction is available by turning black boxes into white ones, which could make the further theoretical analysis easier; 2) The number and locations of measuring stations can be set discretionarily and the same location can be measured repeatedly; 3) New material types and stress parameters can be added freely, thus testing types can be expanded unlimitedly; 4) New data processing methods are added and different methods can be chosen; 5) One of the multiple diffraction peaks can be selected and processed; 6) The experimental data are filtered manually to get rid of invalid ones.Scores of times, the ferrous powder is examined with result values within the range of±20Mpa, which confirms accuracy of the measuring software.To solve the problem that stainless steel, aluminum alloy and titanium alloy are hard to measure using X-ran method, the updated-software system is applied to study the diffraction curves of different materials. The uniform strength beams made of these materials are tested by updated-software system under different loads. The results are also compared with electrometric and theoretical methods and the old system.Conclusion: the results of electrometric measurements to calibrate the uniform strength beams correspond to the theoretical results while all the errors are in 1~3%.1) By the calibrating process for Carbon Steel, the results tested by the functional extended equipment show the same trend as the original equipment, between which the max error is less than 16Mpa. And the average absolute values of 7 times loading errors for Japanese instrument, half-width method and parabola method of this paper are 17.40MPa, 15.54 MPa and 15.59 MPa, respectively.2) Two peaks in the X-Ray diffraction of stainless steel have been observed. It proves that the 127°peak cannot determinate the stress although remarkable, while the 149°peak can reflect the residual stress correctly although unremarkable.3) The trend of aluminum alloy result tested by expanded function X-ray instrument is identical with theoretical and electronic method, but with a fixed difference between them. Those two peaks also exist on the aluminum alloy diffraction curve where the peak position at 156°can determine the stress of aluminum alloy.This research also indicates that, in both stainless steel and aluminum alloy, the peak positions at some angles cannot reflect the genuine changes, and this problem needs further research.