Techalloy 320LR description: Techalloy 320LR has a composition similar to 320, except that carbon, silicon, phosphorus and sulfur levels are kept at lower levels as well as the niobium and manganese being specified at a narrower range. The low melting residuals are limited in this alloy to reduce the possibility of micro-fissuring. It is for this reason that this alloy is often used for welding Type 320 stainless steels.