Use of ni-rod filler metal 44ht for welding si-mo ductile iron exhaust manifolds to stainless steel converter housings

摘要

Automotive design is continually driven toward greater efficiency and cleaner operation. These requirements demand higher operating temperatures, necessitating the use of advanced materials and joining techniques. Coupled with demands for lower cost, this combination of requirements presents a formidable challenge to manufacturers. This paper describes the use of a newly-developed stabilized Ni-Fe-Mn-Cr-Cb welding wire called NI-RODcircleR Filler Metal 44Ht which is used in welding silicon-molybdenum modified ductile iron exhaust manifolds to close-coupled 400 series stainless steel catalyst cans. Use of this product can yield benefits of reduced emissions, greater fuel economy and quieter operation all at lower cost than fabricated stainless steel manifolds. Durability testing of fabricated exhaust components under extreme dynamometer testing has shown that this welding material provides high temperature performance by the ductile iron that is superior to that provided by previously-used welding materials.