Research On Microstructure, Properties And Stress Field Of The Low Strength Match Welding Joint Of The0Crl3Ni5Mo Steel Plate

As an old connection technology，welding plays an indispensable role in industrialproduction and economic construction. With the development of industry, the requirements ofwelding structure are improving. With widely development and utilization of water resourcesin recent years, the low-carbon martensitic stainless steel0Cr13Ni5Mo with thecharacteristics of the high strength, corrosion resistance, wear resistance is widely used inlarge butt welding runner manufacture all over the world. Welding is the most important jointmethod of different parts of runners.Improving the quality of welding joint and controllingwelding stress become the focus research.In this paper,0Cr13Ni5Mo martensitic stain less steel was applied as base metal, andHS367welding wire was applied as the welding material according to the way of the lowstrength match. The CO2gas shielded welding was used. The equilibrium phases werepredicted by CALPHAD method using Thermo-Calc software. The microstructures ofheterogeneous welded joint after welding and annealed were studied by using metalloscope,energy spectroscopy and XRD. As-welded mechanical property of welded joint was studiedby tensile test, impact test and micro hardness. Welding process and annealing process weresimulated by FEM method using MSC.Marc software. Temperature field and stress field ofthe welding plate ware simulated. The result of simulation of residual stress was compared tothe measured value which was obtained by the blind-hole method, both after welding andannealing.The result shows: There is a fusion zone which different from base metal and weldingseam for elements of Cr and Mo diffusion. The fusion zone’s microstructure is martensite,ferrite, austenite and farthing frangible-rigid sigma phase. Inhomogeneous precipitating of thesigma phase in the welding seam resulted in enrichment nearby the fusion zone. Plasticity andtoughness of the welded joint are well, mechanical property of welding seam is weaker.Although heat treatment decreases welding residual stress, the precipitates quantity of sigmaphase is increased. The prediction of welding stress field and annealing stress field is basically realized by the numerable simulation method, the calculated values are lower thanmeasured values.