Investigation On Evaluation System Of Diffusion Hydrogen In Deposited Metal

The existence of diffusion hydrogen in the deposited metal has great harm to the welded joint. The accurate determination of the content of diffusion hydrogen is great significance to make sure the quality and safety of the welding products. In order to make the hydrogen measurement accurate and easy to compare the test results, the national standards GB/T 3965-2012 << Determination of diffusible hydrogen in deposited metal>> already prescribed the mercury method, gas chromatography method, hot-extraction method can be used as the basic method of measuring the diffusible hydrogen, the glycerol method was written in the appendix B. However, when using different methods to measure the content of diffusion hydrogen, the test results are different due to the different collecting media and collecting conditions. This research relies on the most comprehensive diffusion hydrogen detection platform in China, using four kinds of representative welding consumables to research the correspondence between the four methods.The results indicate that the mercury method and the gas chromatography method can be regarded as equivalent reference method. When the temperature of the measuring apparatus used this time was set to be 400oC for the heating process, However due to the test specimen's substance temperature can't reaches 400? and a shorter collection time lead to the measured values only makes up approximately 60 percent which was obtained by mercury method and gas chromatography method, the glycerol method due to it's own reasons,so it is value less than the mercury method's results and the gas chromatography's results. By research 251 groups of experimental data's relative standard deviation shows that, The glycerol method in the determination of low hydrogen welding material, the relative standard deviation will appear larger numerical. In the study samples, the experimental data dispersion degree of the hot-extraction method is minimum, the next one is the mercury method, and the third one is the gas chromatography method, and the glycerol method was the most.By exploring the hot-extraction method's electrical signal curve and the time of collection, determined the best collection time of the hot-extraction method is when the electrical signal and it's slope of the electrical signal curve all become to zero.So this measurement termination conditions can ensure that the hot-extraction method's results and the mercury method's results is consistent.Prepared to use VB calculator procedures for the calculation of the diffusion hydrogen is ready to use. The software not only can calculate the value of each test methods, but also can according to the corresponding relationship between the other three methods to calculate reference value. Software establishes the connection with the Word document and the Access database and can manipulate them.