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Strong Duplex Black Steel Pipe

The time of issue:2014-9-10 10:25:11       Author:

In the duplex black steel pipe, the duplex structure is resistant to stress corrosion cracking, which can affect the stainless steel pipe in hot waters containing chlorides. The most common duplex black steel pipe can be used in many applications such as hot water tanks. Nitrogen can be added to some stainless steels and it is very important in duplex grades. This element has several beneficial effects for black steel pipe. Like nickel, nitrogen promotes austenite and it improves resistance to pitting and crevice corrosion. Duplex black steel pipe is inherently stronger and may have over twice the yield strength when it is used in seagoing chemical tankers. 

In some cases, both strength and corrosion resistance are required so rods and connectors can be made from black steel pipe and stainless steel pipe. What is more, glass curtain walls in public buildings also have high strength and stainless steel pipe can make the structure seem lighter and more transparent. In fact, this is a specialized steel pipe family that has very high strength as long as we add elements such as copper. This is because black steel pipe can form very fine particles during heat treatment and they generally have slightly higher corrosion resistance at best. If corrosion of black steel pipe does occur, it is normally by localized corrosion and the most common forms can be prevented in the first place. For instance, pitting can be localized at individual sites on the surface of black steel pipe. Pitting starts at points in the protective oxide film of stainless steel pipe, such as at manganese inclusions on the steel pipe surface. What is more, we should realize that crevice corrosion takes place where physical crevices are present, such as at the joint between two overlapping black steel pipes. 

We may also see the stainless steel flange and metallic gasket under surface deposits in large stainless steel pipe structure. The mechanisms of black steel pipe pitting and crevice corrosion are similar and both most commonly occur in chloride environments. But it is assisted by the existence of a physical crevice and has to initiate on a black steel pipe surface which is effectively flat. It is often not possible to control environmental factors such as the amount of chloride or the temperature when we use black steel pipe. 

Therefore, it is usually necessary to choose a sufficiently corrosion resistant grade of black steel pipe for the service. An indication of steel pipe corrosion resistance is given and stainless steel pipe is commonly used in the aerospace and defense industries. Therefore, the use of carbon cast steel can be coupled with layered black steel pipe casting on the effective joint with a thick plate of alloy steel.


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