Zhejiang stainless steel sanitary pipe if different components, and its performance is also different materials are welded together, the performance of sanitary stainless steel fittings are not only on the most vulnerable one, while the Japanese are often due to a difference between the two or uneven emergence of new contradictions. For example due to corrosion cell constitutes dissimilar sanitary stainless steel pipe corrosion fatigue life of welded joints, probably than any one material corrosion life are greatly reduced; strength, ductility, elastic modulus can also lead to stress and strain differences in focus, and thus fracture advance ; in addition, such as differences in the thermal expansion coefficient, thermal conductivity, etc. can also cause thermal stress and strain and thermal fatigue damage. Therefore, non-uniformity of composition and properties of welded joints of dissimilar materials inhomogeneities should receive special attention. Zhejiang stainless steel sanitary pipe Typically, components are welded two dissimilar materials, the greater the difference, the weld composition differences sanitary stainless steel pipe weld seam on both sides or one side of the base metal sanitary stainless steel tube is also greater. Sanitary stainless steel pipe weld between the base metal sanitary stainless steel pipe will form a connection with a dissimilar materials deputy. Welding process, in this connection, Deputy, one side is a solid A (or B) base metal sanitary stainless steel tube, one side is a liquid weld pool D component. High temperatures, A (or B), the concentration of the diffusion children Su children (including increased proliferation in some cases) will happen between D, from D to enter the A (or B) in the solid phase ICI table highest inward decreased, not shown in Figure 5-2. By A (or B) D of child elements diffuse into the flow of the liquid due to homogenization, does not affect the local sanitary stainless steel pipe weld components. Weld on one side (or both sides) of the non-uniformity depends on the component A (or B) and D, and each pixel of the wood composition children, it is inevitable; but the depth and its final concentration gradient diffusion, is affected when a lower temperature level and temperature stays. This is a solid weld side (or both sides) of the phase-forming components of an unevenness source.