Type 439 stainless steel is a ferritic, titanium stabilized, 18% chromium alloy material with corrosion resistance that is more or less equivalent to grades 304 and 304L. This type is commonly used in applications such as exhaust system components or tubular manifolds, where Types 304 and 304L and Type 430 may also be considered … Type 439 Stainless; Insights from a San Diego Stainless Steel Slitting Company