The duplex stainless steel

- Sep 29, 2017 -

The duplex stainless steel is in its curing tissue ferrite phase and austenite phase each half, generally the minimum phase content may reach 30%. Due to the characteristics of the two-phase structure, through the proper control of chemical composition and heat treatment process, the DSS combines the advantages of ferritic stainless steel and austenitic stainless steel.

As shown in Figure 1, compared with austenitic stainless steel, duplex stainless steel advantages are as follows:

(1) yield strength than ordinary austenitic stainless steel more than doubled, and the need for molding enough plastic toughness. The use of duplex stainless steel to produce tank or pressure vessel wall thickness than the usual reduction of austenite 30-50%, is conducive to reducing costs.

(2) has excellent resistance to stress corrosion cracking, even with the lowest amount of alloying duplex stainless steel also has a higher resistance to corrosion than austenitic stainless steel, especially in chloride ion environment. Stress corrosion is a common problem that is difficult to solve by ordinary austenitic stainless steel.

(3) the most common use of 2205 duplex stainless steel corrosion resistance is better than ordinary 316L austenitic stainless steel, and super duplex stainless steel has a high corrosion resistance, and then some media, such as acetic acid, Formic acid and so can even replace the high alloy austenitic stainless steel, and even corrosion resistant alloy.

(4) has good resistance to local corrosion, compared with the alloy content of austenitic stainless steel, its wear resistance corrosion and fatigue corrosion resistance is better than austenitic stainless steel.

(5) than the austenitic stainless steel linear expansion coefficient, and carbon steel close to, suitable for connection with carbon steel, has important engineering significance, such as the production of composite panels or linings.

(6) both under dynamic load or static load conditions, than the austenitic stainless steel has a higher energy absorption capacity, which structural parts to deal with emergencies such as collision, explosion, etc., duplex stainless steel has obvious advantages, practical application value The

Compared with austenitic stainless steel, the weakness of duplex stainless steel is as follows:

(1) the application of universal and multi-faceted as austenitic stainless steel, for example, its use temperature must be controlled at 250 degrees Celsius.

(2) its plastic toughness than the austenitic stainless steel low, cold, hot processing technology and forming performance as austenitic stainless steel.

(3) the existence of moderate temperature brittle area, the need for strict control of heat treatment and welding process system to avoid the emergence of harmful phase, damage performance.

2, compared with ferritic stainless steel, duplex stainless steel advantages are as follows:

(1) comprehensive mechanical properties than ferritic stainless steel is good, especially plastic toughness, not as ferritic stainless steel as brittle sensitive.

(2) In addition to stress corrosion resistance, the other resistance to local corrosion is better than ferrite stainless steel.

(3) cold processing technology and cold forming performance is much better than ferrite stainless steel.

(4) welding performance is also far better than ferritic stainless steel, the general welding without preheating, after welding without heat treatment.

(5) Wide range of applications than ferritic stainless steel.

Compared with ferritic stainless steel, the weakness of duplex stainless steel is as follows:

Alloy element content is high, the price is relatively high, the general ferrite does not contain nickel.

In summary, you can generally see the DSS performance and process performance profile, with its superior mechanical and corrosion-resistant comprehensive performance to win the favor of users, has become both a weight-saving and save the investment of excellent resistance Corrosion engineering materials.

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