Dissimilar Welding of Si-Mo Ductile Iron Exhaust Manifold Welded to Stainless Steel Catalytic Converter using NI-ROD Filler Metal 44HT

The demands of modern society continue to drive automotive design to greater efficiency and cleaner operation at lower cost. Higher operating temperatures are now typically required to meet these demands, making the use of more robust materials and joining techniques a necessity. This paper describes how the benefits of reduced emissions and greater fuel economy along with quieter operation are achieved by using silicon-molybdenum modified ductile iron exhaust manifolds welded to close-coupled 400 series stainless steel catalyst cans. This weldment is made possible by using a newly-developed stabilized Ni-Fe-Mn-Cr-Cb welding wire called NI-ROD^® Filler Metal 44HT. Durability testing of fabricated exhaust components under extreme dynamometer testing has shown that this welding material provides successful higher temperature performance by the ductile iron than that provided by previous weldments of the same iron.