Resistance of stainless steel to liquid aluminum attack

Abstract

A modified T316L stainless steel composition provides for improved resistance to liquid metal attack, for instance when exposed to liquid aluminum. The modified composition includes a higher nitrogen, higher molybdenum, or a combination of both along with not having any as-cast delta ferrite phase or minimizing this phase. The modified stainless steel composition adds additional resistance to liquid metal attack from using only refractory coatings to prevent attack by liquid aluminum.

I/We claim: 
     
         1 . A stainless steel comprising by weight percentage about 20% Cr, about 2% to about 7% Mo, about 1% to about 1.3% Si, about 8% to about 14% Ni, at least about 1.25% Mn, about 0.03% C, about 0.03% to about 0.16% N, and the balance impurities, wherein the average ferrite is 0% to about 28% based on Feritscope measurements. 
     
     
         2 . The steel of  claim 1 , wherein the N is equal or greater than about 0.12%. 
     
     
         3 . The steel of  claim 1 , wherein the N is equal or greater than about 0.16%. 
     
     
         4 . The steel of  claim 1 , wherein the Mo is equal or greater than about 2%. 
     
     
         5 . The steel of  claim 1 , wherein the Mo is equal or greater than about 6%. 
     
     
         6 . The steel of  claim 1 , wherein the average ferrite is about 0%. 
     
     
         7 . The steel of  claim 1 , wherein the average ferrite is about 18%. 
     
     
         8 . The steel of  claim 1 , wherein the Mo is about 2% and the N is about 0.12%. 
     
     
         9 . The steel of  claim 1 , wherein the Mo is about 2% and the N is about 0.16%. 
     
     
         10 . The steel of  claim 1 , wherein the Mo is about 7% and the N is about 0.12%. 
     
     
         11 . The steel of  claim 1 , wherein the Mo is about 7% and the N is about 0.16%. 
     
     
         12 . The steel of  claim 2 , wherein the average ferrite is about 0%. 
     
     
         13 . The steel of  claim 3 , wherein the average ferrite is about 0%. 
     
     
         14 . The steel of  claim 8 , wherein the average ferrite is about 0%. 
     
     
         15 . The steel of  claim 9 , wherein the average ferrite is about 0%. 
     
     
         16 . The steel of  claim 10 , wherein the average ferrite is about 0%. 
     
     
         17 . The steel of  claim 11 , wherein the average ferrite is about 0%. 
     
     
         18 . The steel of  claim 1 , wherein the Mn is at least about 2.3%. 
     
     
         19 . The steel of  claim 1 , wherein the Mn is at least about 6%. 
     
     
         20 . The steel of  claim 1 , wherein the Mo is about 1.94% to about 6.74%, the Si is about 1.14% to about 1.27%, the Ni is about 7.88% to about 14.41%, the Mn is at least about 1.25%, the C is about 0.0276% to about 0.0307%, and the N is about 0.031% to about 0.160%.