stainless steel Stainless steel performance
Duplex stainless steel refers to its solid solution in the ferrite microstructure and austenite microstructure of about 50%, usually the minimum phase content should reach 30%, so duplex stainless steel both ferrite Stainless steel and austenitic Which compared with the austenitic stainless steel, duplex stainless steel has more advantages, first of all, its yield strength times stronger than ordinary austenitic stainless steel, also has the necessary molding toughness. The thickness of a tank or pressure vessel made of duplex stainless steel is reduced by 30% to 50% compared to conventional austenitic stainless steels, which is a significant reduction in costs.
Second, the resistance to stress corrosion cracking of duplex stainless steel is very excellent, especially in chloride-containing environments, even with the lowest alloying duplex stainless steel, the ability to resist stress corrosion cracking is higher than that of austenitic stainless steel Stress-resistant corrosion is also a common austenitic stainless steel is often difficult to solve the outstanding problem.
The third point is that the most common 2205 duplex stainless steel is used in many media to have better corrosion resistance than conventional 316L austenitic stainless steels because of the high corrosion resistance of super duplex stainless steels in some media , Such as acetic acid, formic acid, etc. can replace high alloy austenitic stainless steel, and even corrosion resistant alloy.
The fourth point is that duplex stainless steel has a good resistance to local corrosion performance, and alloy content comparable to austenitic stainless steel, duplex stainless steel wear resistance corrosion and corrosion fatigue properties are better than austenitic stainless steel.
The fifth point is that the linear expansion coefficient of duplex stainless steel is lower than that of austenitic stainless steel, close to carbon steel, can be connected with carbon steel, engineering significance, for example, can be used to produce stainless steel composite panels or lining.
The last point is whether in dynamic load or static load conditions, duplex stainless steel energy absorption capacity than the austenitic stainless steel is better. In dealing with unexpected accidents such as collision, explosion, the actual value of duplex stainless steel is very obvious.
But compared with austenitic stainless steel, duplex stainless steel is also a disadvantage. The first is the application of duplex stainless steel and multi-faceted than austenitic stainless steel, such as long-term use of its use temperature must be controlled at 250 ℃ below.
Followed by its plastic toughness is lower than the austenitic stainless steel, its cold, hot processing technology and molding performance than the austenitic stainless steel.
Duplex stainless steel also exists in the temperature brittle area, the need for strict control of heat treatment and welding process system to avoid the emergence of harmful phase, damage performance.
Duplex stainless steel and austenitic stainless steel compared to the most obvious weakness is that the former contains a lot of ferrite.
Let's talk about two-phase stainless steel and ferritic stainless steel compared to what advantages and disadvantages. Advantages of the first comprehensive mechanical properties than ferritic stainless steel, especially plastic toughness. Fuselage is not as sensitive as ferrite stainless steel. Followed by resistance to stress corrosion resistance, the other resistance to local corrosion is better than ferrite stainless steel. Dual-phase stainless steel cold processing technology and cold forming performance is much better than ferrite stainless steel. Another duplex stainless steel welding performance is also much better than ferritic stainless steel, generally do not need to preheat before welding, after welding without heat treatment. Another point is that the use of duplex stainless steel than ferritic stainless steel wide.
However, compared with ferritic stainless steel, duplex stainless steel is one of the weak elements of its high content of alloy, the price is relatively high, it is because the ordinary ferritic stainless steel does not contain nickel.Stainless Steel Bar.