90 degree 4" weld on elbow, stainless steel 304 stainless steel weld on elbows are primarily used to weld two lengths of piping together to create a solid pipeline with a change in direction. Stainless steel elbows and piping are perfect for use in any food service or industrial setting, and are a preferred method for transferring a large variety of liquids and gases. These elbows are 4" in diameter, and set at a 90â° angle. They are manufactured out of 304 food grade stainless steel, and meet all of todays sanitary standards for sanitary fittings.