Schedule 40 Stainless Steel Pipe is a type of steel pipe that can be used for different kinds of piping. There are uses for air, oil, water, and natural gas, among others. The sch40 pipes are made out of different grades of steel. It is especially resistant to corrosion from chloride ions, which can cause stress cracks. The material also has less carbon, which makes it easier to weld and less likely to rust in one spot. Pipes should be less than 10 inches in diameter. Smaller pipe lines use the 1 inch Schedule 40 Stainless Steel Pipe The weight of schedule 40 steel pipes also changes based on how big they are. In general, the weight of sch 40 pipes per foot is 1.68 lbs.