Elbow, which is made by stamping a flat piece of material identical to the pipe material into a semi-circular shape, and then welding the two semi-circular pieces together to form a complete elbow. Due to varying welding standards for different types of pipes, it is typically assembled and spot-welded as a semi-finished product for shipment, with on-site construction welding based on the pipe weld grade. Therefore, it is also known as a two-piece welded elbow.