Advantages and disadvantages of duplex stainless steel pipe and other stainless steel pipe

So-called duplex stainless steel pipe is a solid solution of tissue iron element in the bulk phase and austenite meet each half, generally at least phase content also need to reach 30% so it both iron element of stainless steel pipe and austenitic stainless steel pipe performance characteristics.
Compared with austenitic stainless steel pipe, the advantages of duplex stainless steel pipe are as follows:
The yield strength is more than twice as high as that of the conventional austenitic stainless steel pipe, and the yield strength is sufficient for the plastic toughness. The use of duplex stainless steel pipe production tanks or pressure vessel wall thickness than commonly used austenitic stainless steel pipe to reduce the cost of 30%~50%.
2. It has excellent resistance to stress corrosion cracking ability, especially in chlorine ion in the environment, even with lowest duplex stainless steel pipe alloy is than that of austenite stainless steel pipe higher resistance to the ability of stress corrosion cracking and stress corrosion is common austenitic stainless steel pipe is difficult to solve the outstanding problems.
3 in many media most commonly applied 2205 duplex stainless steel pipe resistant corrosion than ordinary 316L austenitic stainless steel pipe and super duplex stainless steel pipe with high corrosion resistance, some media, such as acetic acid, formic acid and can even replace the high alloy austenitic stainless steel pipe, and corrosion resistant alloy.
(4) has good resistant to localized corrosion, austenitic stainless steel pipe and alloy content compared to in view of the duplex stainless steel pipe with high strength and good corrosion resistance, abrasion corrosion and corrosion fatigue properties are superior to the austenitic stainless steel pipe.
Fifthly, than austenitic stainless steel pipe wire expansion coefficient is low, and carbon steel close, is suitable for connecting with carbon steel, has important engineering significance, such as the production of composite sheet or lining.
6 in dynamic or static loading conditions than the austenitic stainless steel pipe has higher energy absorption ability. This structure to cope with unexpected accidents such as collision, explosion, duplex stainless steel pipe advantages are obvious, there is practical value.
Compared with austenitic stainless steel pipe, duplex stainless steel pipe is as follows:
The universality and versatility of the application are not as good as austenitic stainless steel pipe, for example, the temporary application of the temperature must be controlled below 250.
Its toughness is lower than that of austenitic stainless steel pipe, and the cold, hot working process and forming performance are not as good as that of austenitic stainless steel pipe.
In the presence of medium temperature brittleness zone, it is necessary to strictly control the heat treatment and welding process system, in order to prevent the harmful phase of the present, damage performance.
The disadvantage of duplex stainless steel pipe and austenitic stainless steel pipe is that there are a large number of ferrite microstructure in duplex stainless steel pipe.
Compared with ferritic stainless steel pipe, the advantages of duplex stainless steel pipe are as follows:
The comprehensive mechanical properties are higher than that of ferritic stainless steel pipe, especially plastic and toughness. Brittleness is not as sensitive as ferritic stainless steel pipe.
In addition to the stress corrosion resistance, other local corrosion resistance is better than that of ferritic stainless steel pipe.
The performance and cold forming performance of the cold working process are much better than that of the ferritic stainless steel pipe.
The welding performance is far better than ferritic stainless steel pipe, usually without preheating before welding, without heat treatment after welding.
The application range is wide ferritic stainless steel pipe.
Compared with stainless steel pipe, the duplex stainless steel pipe has the advantage of being a large amount of austenite in duplex stainless steel pipe. Compared with ferritic stainless steel pipe, the other disadvantage of duplex stainless steel pipe is the high content of alloying elements, the price is relatively high, and the general ferritic stainless steel pipe does not contain nickel.
To sum up, we can briefly see duplex stainless steel pipe use properties and processing properties of the whole picture, with its superior mechanical and corrosion resistance of the comprehensive performance to win the favor of users, has become not only save weight and save investment of excellent corrosion resistant engineering materials.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)

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