Abstract: A method of manufacturing an exhaust gas manifold, that includes metal exhaust pipes and metal flanges for attaching the pipe openings to corresponding internal combustion engine exhaust ports, employs a hybrid MIG welding process to reduce the occurrences of weld spatter being deposited on the pipe surfaces. Additional benefits are a reduction in applied energy, a resultant reduction in heat being applied to the work pieces, less consumption of weld wire, and improved efficiency of making the weld on the inside surface of the flange adjacent to the pipe opening. The hybrid MIG technique involves moving the head of the weld gun so that its weld wire tip is in contact with the closed path joint formed between an aperture in the flange and the pipe opening. Electrical energy is then applied between the weld wire and the work pieces (flange and pipe) for a relatively short period of time that is sufficient to cause the tip of the weld wire to become a molten drop.

Abstract: A method of manufacturing a torque arm assembly for use in an automotive vehicle utilizing a cold hybrid MIG technique to minimize the introduction of excessive heat into the welded sheet metal panel components of the assembly. Outer and inner metal panels of the assembly are formed with edges along their lengths and are mated with their overlapping edges forming a joint that is welded. The cold hybrid MIG technique involves moving the weld gun so that its weld wire tip is in contact with the outer surface of the inner panel. Applying electrical energy between the weld wire and the panel for a period of time that is sufficient to cause the tip of the weld wire to become a molten drop. Terminating the application of electrical energy and moving the weld wire away from contact to allow the molten wire drop to enter the joint and form the weld. Repeating the weld steps at a high frequency at each point along the joint to is complete the weld along its length.

Abstract: A catalytic converter for an automotive exhaust system or the like comprises a catalyst substrate within a midsection of a metal housing. The metal housing includes an end section that extends from the midsection and includes an opening, which may be either an inlet or an outlet for the catalytic converter. An inner heat shield is disposed within the end section and includes a flared section that is spaced apart from the housing end section to provide thermal insulation. The flared section is formed of a metal sheet and includes one or more ribs to reinforce the flared section and reduce vibration that might otherwise produce noise. Preferably, the ribs are formed by elongated ridges that extend generally in the direction of gas flow through the converter.