Originally Posted by overbored
The L does stand for low carbon but has nothing to do with rust. both 316 and 304 alloys of stainless steel come in an L variation. it is the extra chromium in the 316 that makes it more corrosion resistant than 304. the L does make the alloy less affected by chromium carbide precipitation after welding which can have an effect on intergranular corrosion of the welding heat effect zone
Is there any easy way to tell if they use the product you spec? How can you tell different grades of SS, unless you provide your shop with the product.