COMPLEX ARC-WELDING FOR CLAD STEEL AND A CONCEPT OF ITS COMPUTER-SIMULATION SYSTEM - COMPLEX ARC-WELDING PROCESS .2.

A new complex arc welding process is proposed. The aim is to achieve h igh production efficiency and high welding quality required in a small batch production. The process combines some element welding methods t o obtain optimum multi-layer weld. The element welding methods are TIG , MIG (MAG), and their add-on function versions using filler wire(s) a nd magnetic control together. The process selects appropriate element welding for each individual pass considering the characteristics of be ad formation. An application of the complex arc welding using of some element welding methods to the stainless clad steel has been investiga ted to obtain the fundamental data, such as the bead formation, weld m etal, pass numbers and mechanical proper-ties. Experiments showed the following results. Some combination of element welding methods reduce the penetration compared with TIG or MIG welding, resulting in decreas ed dilution of Ni and Cr in stainless steel. The deposition rate rises without spoiling welding speed and operability. The Ni and Cr content s in the weld metal of the TIG added with a filler wire and magnetic c ontrol is higher than that of TIG welding. The tensile fracture of wel ds in the complex process occurred in the portion from the base metal to HAZ, and that in the single process occurred in the base metal. The tensile strength of welds in the complex process is equal of in the s ingle process, and its value is equivalent or superior to the 570 MPa strength of conventional clad steel. The peak of hardness in the weld metal is lower and the hardened region is narrower compared with TIG a nd MIG welding. Using the above results, this paper further proposes a concept of the computer simulation system of a 'complex arc welding p rocess' for automatic selection and application of a suitable element welding method and welding conditions to poduce the required bead prop erties in each pass and each layer.