Steel Pipe Group - RHS SHS CHS Galvanized steel pipe: 2017

Tuesday, December 5, 2017

Tianjin erw black steel pipe

As one of the largest welded steel pipe production bases in the north of China, Tianjin steel pipe is playing a very significant role in the steel pipe market. Tianjin erw black steel pipe is very popular among people at home and abroad. Black steel pipe is generally considered non-galvanized steel pipe compared with galvanized one. During the production of the black steel pipe, there will be kind of black oxide substance formed on its surface, which is one reason that people are used to name it black steel pipe. 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.

As for the modern techniques of Tianjin erw black steel pipe, scientific advancement has greatly improved after the butt-weld method invented by Whitehouse. Today, with modern automatic machines, it has become possible for steel pipe manufactures to produce black steel pipes under the extremely high temperature and pressure. What’s more, it will somewhat facilitate steel pipe suppliers to satisfy different diameter requirements for customers. Meanwhile, with the development of modern manufacturing equipment and inventions in electronics, Tianjin black steel pipe quality can be guaranteed strictly following various manufacturing standards. It is much likely that modern manufacturers will use special X-ray gauges to ensure uniformity in wall thickness of steel pipe in the coming days.

In most applications, black steel pipe’s tensile strength makes it a better choice for people to convey water and gas in rural and urban areas. Besides, round steel pipe can also be used to protect electrical wiring and deliver high pressure steam and air. 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 addition, its high heat resistant feature makes it possible to deliver hot water but not drinking water. In our daily life, we can often find the sewages made of the black steel pipe. However, there is no doubt that black steel pipe cannot be used to deliver drinking water.

Tianjin erw black steel pipe has different shapes for your choice in the project, such as square steel pipe, round tube and square & rectangular pipe. Furthermore, take square steel pipes for an example, due to the size, wall thickness, diameter and some other different processing methods, they will be applicable to different actual purposes in real life. Meanwhile, they will undergo further welding processing, heat treatment and other procedures for the final finished products.

Sunday, December 3, 2017

Structural steel tube applications in life

As a rule, a structural steel shape is a profile, formed with a specific cross section and following certain standards for chemical composition and mechanical properties. 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.

Structural steel tubes have been widely used as one kind of building materials in the construction industry for many years due to its strength and stability in use. For example, the flat square surfaces of rectangular steelpipe can ease construction, and they are sometimes preferred for architectural aesthetics in the exposed environments today. Furthermore, structural steel pipe is considered an environment friendly building material in construction industry. Also, some structural steel members, such as I-beams, have high second moments of area, which allow them to be very stiff in respect to their cross-sectional area. In addition, hollow structural sections offer advantages of corrosion protection in applications. Some hollow sections have rounded corners resulting in a better protection than that with sharp corners. This is especially true for the joints in circular hollow sections where there is a smooth transition from one section to another. Meanwhile, this better protection increases the protection period of coatings against corrosion. With regard to steel pipe price in the market, cold formed structural steel tube are relatively high than the hot finished ones. Besides, from the aesthetic viewpoint, cold formed structural steel pipe has a smooth surface, while hot finished sections can be pitted, which can be considered an issue for architecturally exposed structural steel for certain applications.

Compared to other traditional construction materials, structural steel frame is stronger because it was further enhanced by steel reinforcing process. The increase in its standard strength is greater than the total strength of other competing highly strong materials. Today, some steel pipe manufacturers are trying to make customized shapes as per the specific requirements of clients in the world. For example, the elliptical hollow sections have become more popular for architectural designs. Of course, you can often find that some other shapes of structural steel pipes have been used in a variety of infrastructure construction around us.

Thursday, November 30, 2017

How to recognize steel tube failure？

Steel pipe corrosion is a diffusion-controlled process on exposed surfaces, which converts a refined metal to a more chemically-stable form, such as its oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually metals) by chemical and/or electrochemical reaction with their environment. In the steel and iron industry, most types of steel tube corrosion come with a continuous and virtually unstoppable process. Corrosion degrades the useful properties of steel pipes including strength, appearance and permeability to liquids and gases.

Most people commonly believe that many structural alloys corrode merely from exposure to moisture in air. Nevertheless, the corroding process starts in essence from the strong reaction with certain substances in environments. Here we would like to talk about a few common steel pipe failures in applications.

1. Uniform corrosion

Uniform corrosion or general corrosion, is defined as a type of corrosion attack (deterioration) that is more or less uniformly distributed over the entire exposed surface of cold rolled steel pipe. Uniform corrosion also refers to the corrosion that proceeds at approximately the same rate over the exposed metal surface. Specifically, cast irons and steels corrode uniformly when exposed to open atmospheres, soils and natural waters, leading to the rusty appearance.

2. Interior Pipe Deposits

For round steel pipe in applications, internal rust deposits, commonly termed tuberculation, are an inevitable death sentence for most piping systems. They are the lighter and less dense end product of steel tube corrosion. Once established by high and uncontrolled corrosion conditions, internal deposits initiate much greater deep pitting. The highest corrosion loss is more likely at horizontal lines and in low flow or dead end areas where rust and other deposits will settle, but can affect vertical lines and main risers as well. Random areas of high tuberculation are actually the result of a high pitting or cell corrosion condition directly beneath it, with the volume or height of the rust deposit directly proportionate to the depth and volume of pipe wall loss.

3. Weathering Damage

Generally speaking, weathering damage subject to rain, snow, atmospheric conditions, or cooling tower, overspray is the easiest to prevent. The piping is exposed and accessible, with corrosion activity always visually obvious. Most weathering damage requires decades to produce a failure, and is simply due to a lack of maintenance. Smaller diameter piping is always most vulnerable due to its inherently lesser wall thickness.

Of course, with regard to different types of pipe corrosion & failure in use, pipe repair work usually takes on various forms, ranging from temporary clamps to the replacement of entire piping systems. On the other hand, steel pipe manufacturers have various kinds of methods of surface treatment for steel tube done as precautions in a mill.

Tuesday, November 28, 2017

How to make galvanized coating for steel pipe?

How to make galvanized coating for steel pipe？

As it is well acknowledged, galvanized steel pipe is a steel pipe that has been coated with zinc in order to form certain protective layer on the surface of pipe. This coating generally protects the steel from corrosion. Hot dipped galvanized steel pipe is one typical pipe of galvanized pipes in the steel pipe market. As a rule, before the production of galvanized steel pipe, steel materials are placed into a molten bath of zinc. And this process is also called hot dip galvanization. Normally, the two kinds of metals are chemically bound to one another in this processing, and will therefore never separate, resulting in a more resistant and longer lasting version of steel at a mill.

Today, hot dipped galvanized steel pipe has got a large sales share both in the domestic and foreign steel pipe market. Furthermore, due to its wide range of practical applications, galvanized pipe has won the favor of users in the real life. When it comes to galvanized steel pipe, we have to say about its long story of processing technology in history. According to reliable written records, the process of galvanization was first discussed by scientists in the 1770s, nearly 60 years before it was finally introduced in the 1830s. French engineer Stanislaus Tranquille Modeste Sorel took out the first patent for the process in 1937, and began manufacturing it soon after. By the 1850s, Europe was producing galvanized steel out of manufacturing plants located around the continent. The United States followed shortly thereafter, opening its first plant in the 1870s.

In the actual process of the production of galvanized steel pipe, it is necessary for steel pipe manufacturers to have certain professional knowledge of the galvanized coating. In general, factors influencing the thickness and appearance of the galvanized coating include chemical composition of the steel materials, steel surface condition, cold-working of steel prior to galvanizing, bath temperature, bath immersion time, bath withdrawal rate, and steel cooling rate. With reference to the coating thickness, the American Society of Testing and Materials International (ASTM), the Canadian Specification Association (CSA) and the American Association of State Highway and Transportation Officials (AASHTO) specifications establish minimum standards for thickness of galvanized coatings on various categories of items. These minimum standards are routinely exceeded by galvanizers due to the nature of the galvanizing process. On the other hand, the thickness of the zinc layer will also make certain effects on the steel pipe price in the market.

At the end, we have to say that the differences in the luster and color of galvanized coatings do not significantly affect corrosion resistance. The presence or absence of spangle has no effect on coating performance. The well-known spangled appearance found on galvanized products is a crystallization process dependent upon the zinc bath chemistry, the rate of cooling, the method of pickling, the steel chemistry, and the thickness of the coating. Dull gray or patchy matte gray galvanized coatings give a service life equal to bright or spangled coatings since the service life depends on the zinc coating thickness.