Black steel pipe’s tensile strength makes it a better choice for people to convey water and gas in rural and urban areas. The oil and petroleum industries widely use black steel pipe for convey large quantities of oil through remote areas. Although it doesn’t have a corrosion resistant layer like the galvanized steel pipes or other welded steel pipes, its high fire resistant performance plays an important role in fire sprinkler system. In most cases, how to extend the service life of black steel pipe in applications has become a topic issue for users now and then.
It can not be denied that steel pipe is a product that tends to be prone to corrosion in service especially under certain harsh conditions. There are many types of metal surface treatments for steel pipe in a mill today. For one thing, fabrication services such as metal finishes will generally add to delivery time on your order. For the other thing, a proper coating can become a effective protective film for steel pipe against any damages or breakdown in order to extend the service life in applications. With regard to hot dipped galvanized steel pipe, galvanizing has been used to protect iron and steel from rusting for over a hundred years in the iron and steel industry. Galvanizing is simply coating of zinc over steel products. Like paint, galvanized coating protects steel products from corrosion by forming a barrier between the steel base and the environment, but galvanizing goes one giant step further than paint. Besides, it can provide electrochemical protection of some cold rolled steel pipes in applications. Since zinc is electrochemically more reactive than steel, it oxidizes to protect the steel near it. As a result, even if a galvanized steel surface is scratched down to the bare steel, the galvanizing coating will prevent the steel from rusting. In addition, anodizing is an electrochemical process that forms a protective coating of aluminum oxide on the surface of aluminum. Aluminum oxide is a hard, durable, weather resistant substance. The coating is integral to the metal and cannot peel or flake.
In some cases, there maybe exist welding defects for black steel pipe in service over time. Technically speaking, welding defects are a type of discontinuity that compromises the usefulness of a weldment, which could render it unable meet minimum applicable acceptance standards/specifications. In recent years, more and more steel pipe manufacturers in China begin to pay much attention to the improving the welding technology involving weld toughness, porosity control, weld appearance, restoring corrosion resistance and other issues in a mill.