Hello! First explain ER321 (not ER-321) wire stainless MIT wire, mainly for the MIG (high efficiency generally plate thickness greater than 3mm). TIG (low efficiency, the general thickness thicker plate thickness) of not more than 6mm or important structures are generally not used for other welding methods. ER321 not flux cored wire, but solid wire. The wire grades for the American Welding Society: AWS A5.9 ER321 national standard: GB / T 4241 H08Cr19Ni10Ti. The weld metal by adding titanium to carbon sequestration, and to prevent intergranular carbide precipitation, and improved resistance to intergranular corrosion of welds with good mechanical properties. An example of the chemical composition of the wire (%): C: 0.028 Mn: 1.85 Si: 0.45 S: 0.010 P: 0.019 of Cr: 18.92 of Ni: 9.25 Ti: 0.34 Mo: 0.007 of Cu: 0.07 Example of weld metal mechanical properties: tensile strength Rm (MPa) 575 Elongation A (%) 40