Ferritic Stainless Steel with Excellent Oxidation Resistance, Good High Temperature Strength, and Good Formability

Abstract

Ferritic stainless steels with good oxidation resistance, good high temperature strength, and good formability are produced with Ti addition and low Al content for room temperature formability resulting from equiaxed as-cast grain structures. Columbium (niobium) and copper are added for high temperature strength. Silicon and manganese are added for oxidation resistance. The ferritic stainless steels provide better oxidation resistance than ferritic stainless steels of 18Cr—2Mo and 15Cr-Cb-Ti—Si—Mn. In addition, they are generally less costly to produce than 18Cr—2Mo.

What is claimed is: 
     
         1 . A ferritic stainless steel comprising the following elements by weight percent:
 0.020% or less carbon   0.020% or less nitrogen   15-20% chromium   0.30% or less titanium   0.50% or less columbium   1.0-2.00% copper   1.0-1.7% silicon   0.4-1.5% manganese   0.050% or less phosphorus   0.01% or less sulfur   0.020% or less aluminum   
     
     
         2 . The ferritic stainless steel of  claim 1 , further comprising at least one of the following elements by weight percent:
 3.0% or less molybdenum   0.010% or less boron   0.5% or less vanadium   1.0% or less nickel