作者：tjdpbdarticle

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.

Black steel pipe is named for the black oxide substance formed on its surface, which is one popular member of steel pipe kingdom in the steel pipe market today. However, the black oxide substance has no capacity of anticorrosion and antirust. In other words, it is necessary to take some measures to protect the black steel pipe from rusting in daily applications.

In the recent years, surface finishing is a broad range of industrial processes that alter the surface of a manufactured item to achieve a certain property. Finishing processes can be employed to black steel pipes: improve appearance, adhesion or wettability, solderability, corrosion resistance, tarnish resistance, chemical resistance, wear resistance, hardness, modify electrical conductivity, remove burrs and other surface flaws, as well as control the surface friction. In a few cases, some cold rolled steel pipes are manufactured with some types of coatings to restore original dimensions to salvage or repair an item. An unfinished surface is often called mill finish. There are numerous types of metal finishing processes that can be used for a variety of purposes. For example, powder coating applies a decorative finish that is similar to paint, but with greater durability. The process involves melting dry plastic powder onto the metal to produce a textured, matte, or glossy coating. A textured powder-coating machine is also highly effective in removing surface defects.

When it comes to hot dipped galvanized steel pipe in the current market, we have to give a talk about hot dipped galvanizing. It is the process of dipping fabricated steel into a kettle or vat containing molten zinc. The process is inherently simple which provides a distinct advantage over other corrosion protection methods. While the steel is in the kettle, the iron in the steel metallurgically reacts with the molten zinc to form a tightly-bonded alloy coating that provides superior corrosion protection to steel pipes in service.

Passivation is another important method to protect black steel pipe from corrosion in applications, which is widely applied to some structural steel pipes used outdoors. As a rule, this chemical treatment simply augments / expedites the naturally occurring process when the material is exposed to oxygen in the atmosphere. It simply helps “grow” the inert, oxide layer faster and thicker than found naturally. Some specifications call for use of sodium dichromate added to the acidic baths solutions to provide more rapid formation of the oxide layer or passivation film. This practice of using sodium dichromate is becoming less and less prevalent with the significant advancements in ultrasonics and citric acid known as citrisurf which encourage oxygen formation at the surface of the material while the material is still in immersion of the acid bath.

In the current steel pipe market, structural steel pipes have been widely used as one kind of building materials in the frame scaffolding for many years due to its strength and stability in use. Since the 70s, China has imported from Japan, the United States, Britain and other countries frame scaffolding system, and has been widely applied in a high-rise building construction. The sections of frame scaffolding not only provide workers with a place to work from, but the sections also act as a ladder to allow workers a way to reach the desired working height. Seamless pipe and welded steel pipe are two common types of hollow structural sections in use in the current steel pipe market. Structural steel shapes, sizes, composition, strengths, storage practices, etc., are regulated by standards in most industrialized countries. And each project is judged on its use of structural steel from both an architectural and structural engineering perspective.

Generally speaking, frame scaffolding is one of the most common types of scaffolding, often seen on construction sites worldwide. In the majority of cases, it cannot be denied that when frame scaffolding is in good condition and erected properly, it will provide a stable elevated work platform at virtually any height so that workers can easily and safely work anytime. Unlike other structural steel materials, galvanized steel pipe is immediately ready for use when it is delivered. No additional preparation of the surface is required, no time-consuming inspections, additional painting or coatings are needed. Once the structure is assembled, contractors can immediately begin the next stage of construction without having to worry about the galvanized steel materials.

Galvanized steel pipe generally has the rational cost effective in the market. Compared with other typical steel pipe coatings, such as specialized painting and powder coating, galvanization is much more labor-intensive, resulting in a higher initial cost for contractors. Besides, due to its durability and anti-corrosive properties, galvanized steel pipe can recycled and reused, which to some degree save a lot of money during the post maintenance work. Hot dipped galvanized pipe has been considered popular a lot among many users today. For one thing, the galvanization process protects the steel from rusting damage that can occur during transportation, installation and service. The zinc layer on the surface of pipe can form a barrier protection for steel products to extend the service life in applications. For the other thing, this layer is also resistant to wear and scratches, which makes the steel look more attractive.

Seamless pipe and welded steel pipe are two common types of hollow structural sections in use in the current steel pipe market. Structural steel shapes, sizes, composition, strengths, storage practices, etc., are regulated by standards in most industrialized countries. And each project is judged on its use of structural steel from both an architectural and structural engineering perspective.