No matter seamless or ERW steel pipe, we cannot avoid the most important step which is connection. This step would be essential for each time’s transmission of water, oil, gas and other flood goods by steel pipes.

There is a chart for the comparison of four kinds of steel pipes’ connection. They are butt weld, flange all types, threaded, socket weld, glued, brazed and grooved end. From the chart, we can see that the main difference is the middle of the connection part.

Butt weld is no extra objects are added. A flange is a plate or ring that is attached to a pipe. Two flange pipes then create a tight seal by being bolted together. The pipe is the male fitting and the socket is equivalent to a female fitting. To provide a tight seal it is best to line the outside of the pipe and the inside of the socket with a sealant. A grooved end fitting has a groove or shoulder along the edge. This fittings groove allows for a seal without the need for welding.