Assessment of Delta ferrite for SA 240 Type 304L Austenitic Weld Metal using Different Filler Materials [ READ ]
Rati Saluja, K. M. Moeed
A minimum of ferrite number FN 4 and a maximum of ferrite number FN 21 are essential to prevent hot cracking in austenitic stainless steel. It’s essential to restrict the amount of delta-ferrite as material becomes magnetic. Above ferrite number more than FN 21 delta ferrite can be harmful to the welded area due to the transformation of ferrite to sigma phase. To restate, steel with ferrite numbers between 4 and 21 solidify as primary ferrite with austenite. Delta ferrite content is limited by the content of chromium, nickel, carbon, manganese, molybdenum, silicon, copper, nitrogen, and niobium. Therefore to formulate effect of ferrite on microstructure the MIG welding process is performed with different filler wires, to predict suitability of filler materials with respect to weld metal on the basis of ferrite number and composition. To determine the suitable composition and the corresponding ferrite numbers for type SA 240 Type 304L Schaeffler Diagram, WRC 1992 Diagram and magnetic induction method is used.
Rati Saluja, K. M. Moeed
A minimum of ferrite number FN 4 and a maximum of ferrite number FN 21 are essential to prevent hot cracking in austenitic stainless steel. It’s essential to restrict the amount of delta-ferrite as material becomes magnetic. Above ferrite number more than FN 21 delta ferrite can be harmful to the welded area due to the transformation of ferrite to sigma phase. To restate, steel with ferrite numbers between 4 and 21 solidify as primary ferrite with austenite. Delta ferrite content is limited by the content of chromium, nickel, carbon, manganese, molybdenum, silicon, copper, nitrogen, and niobium. Therefore to formulate effect of ferrite on microstructure the MIG welding process is performed with different filler wires, to predict suitability of filler materials with respect to weld metal on the basis of ferrite number and composition. To determine the suitable composition and the corresponding ferrite numbers for type SA 240 Type 304L Schaeffler Diagram, WRC 1992 Diagram and magnetic induction method is used.
