Experimental Studies of Different thick Steel sheets and variable clearance in MIG Brazing

Abstract

Current automotive industry trend is developing the new materials and technologies for automobile BIW to enhance the latest stringent requirements like safety, weight and safer body. Main aim is to reduce the weight of body without compromising the targeted quality and safety norms. One of the solutions is different grades of steel sheets and different thickness combination are used combinedly to weld depend on the function of the designed structural component. Reduction of weight is searched most in the recent high strength steels. Target is to reduce dead load and reduce the cost. In this scenario roof outer and inner panel which is having closed ring type assembly. For ring panel assembly different thickness materials and variable clearance joinery is welded by MIG brazing tags. As per benchmark study the strongest joint 930.8 Mpa is achieved when the joint clearance is .038mm. When the clearance is narrower than it’s harder for the filler metal to distribute itself adequately throughout the joint and joint strength is weakened. Conversely, if the gap is wider than necessary, the strength of the joint will be reduced almost to that of the filler metal itself. But in ordinary day-to-day brazing, need not this much precise to get a sufficiently strong joint. In this study analyzing the tensile shearing strength of the joinery with respect to the thickness and variable clearance. Also, parameters contributing to the strength variation. MIG brazing welding processes is using CMT machine and CuSi3 of brazing wire.