Ray law and stress release a law to measure level the comparative research of welding stress

Occupy about in the weight that structural member solders in project machine overall the 60% ～ of weight 75% , criterion at soldering the tall leftover stress in contact meets those who cause steel structure be out of shape, brittleness ruptures, exhaustion is destroyed and stress corrodes craze to wait, so understanding solders the remains in the structure promulgates with respect to force, ensure solder the on the safe side of the quality of steel structure is very important. Solder commonly usedly the test method of structural remains internal stress, by its the principle can divide it is two kinds big: Stress releases machinery to measure the physics of law and nondestructive to measure a way. As a result of electric shade meet an emergency piece report measures law and rigid standard cooperate to use, lowered rigid standard greatly to component part ruinous; More commonly used is diffraction of X smooth ray measures a way in physical law. The article measured the music of the result to make more in detail comparative discussion with the dot to measuring measurement technique two kinds, understand from academic and aspirant birthday commentate. One, the high strenth of 15MnVN normalizing low alloy that capable person of experimental process mother is 500MPa class steel, ply 20mm, use semi-automatic CO2 gas to protect solder, welding wire uses H04Mn2SiTiA. Contact dimension is shown 1 times like the graph. Contact is to because tack welding is cabined,nodding what undertake below condition solder, in each measurement point abrade, electroanalysis XYL is used after polishing- - 75 model X ray stress determines appearance measures leftover stress, release a law in stress of same point reoccupy next (double bar meet an emergency is beautiful) measure stress. If pursue,measuring the place is respectively the show welding line of 1 is fore-and-aft central line, weld junction and perpendicular the B line at welding line. 2, with the analysis as a result experimental result expresses to be in graph 2 in, parallel expresses with σ L at the stress with fore-and-aft welding line, perpendicular express with σ T at the transverse stress of welding line. From the graph 2 (A) and (B) can see, outside affecting an area with heat except welding line, of the leftover stress that measures with two kinds of methods promulgating is to comparative of be identical. The precision that this shows to with X ray diffraction the law measures stress and stress release a law go up in same standard. And go up in welding line and weld junction, the measurement of two kinds of methods is put in apparent difference as a result, if pursue 2 (C) (D) be shown. In welding line fore-and-aft reach its except two end around outside, the numerical value that releases a law to measure native place and leftover stress with stress is equal to approximately succumb the limit, and the stress numerical value that measures with X ray law was not achieved succumb the limit. Appear the reason of this kind of phenomenon is: Field of inhomogenous in the cooling process after solder temperature distributings the welding line that cause and the drawing plasticity that heat up influence area are out of shape, right now the metal is become by ferrite photograph α and class of pearlite photograph θ , and of pearlite succumb the limit and Yang Shimo are measured all prep above ferrite, right now every photograph in welding line happens be out of shape, the principle is shown 3 times like the graph. Because ferrite is matrix, and measuring stress with X ray decide through measuring the change of brilliant face span stress is numeric, the stress value that measures with X ray law so is corresponding ferrite only the weighted average of photograph and pearlite photograph. As a result of this one reason, the stress value that affects an area to be measured in welding line and heat with two kinds of methods is abhorrent. Must notice, the stress that measures with X ray law is not the stress in steel however the stress of ferrite photograph. If be like substrate to did not produce plasticity to be out of shape, criterion ray law, doing not have gotten stress to be able to be regarded is steel is medium stress. The stress that the leftover stress value in weld zone can measure from X ray law is worth proper correction to calculate. 3, conclusion is soldering with X ray law the leftover stress that measures on contact mother capable person and the outcome that measure with rigid standard have very good consistency, and the leftover stress that measures in weld zone with two kinds of methods is worth existence a few difference, this one contradictory phenomenon can explain the base line stress in be steel is the stress that ferrite and pearlite are in balance position to fall. CNC Milling