Questions about the characteristics and chlorine corrosion resistance of dual-phase steel 00Cr18Ni5Mo3Si2

The so-called duplex stainless steel has half of the ferrite phase and half of the austenite phase in its solid-quenched structure. Generally, the minimum phase content may reach 30%. Due to the characteristics of the two-phase structure, DSS has the advantages of both ferritic stainless steel and austenitic stainless steel through correct control of chemical composition and heat treatment process. 1. Compared with austenitic stainless steel, the advantages of duplex stainless steel are as follows: (1) The yield strength is more than twice that of ordinary austenitic stainless steel, and it has sufficient plastic toughness required for forming. The wall thickness of storage tanks or pressure vessels made of duplex stainless steel is 30-50% lower than that of commonly used austenite, which is beneficial to reducing costs. (2) It has excellent resistance to stress corrosion cracking. Even duplex stainless steel with the lowest alloy content has a higher resistance to stress corrosion cracking than austenitic stainless steel, especially in environments containing chloride ions. Stress corrosion is a prominent problem that is difficult to solve for ordinary austenitic stainless steel. (3) The corrosion resistance of 2205 duplex stainless steel, which is the most commonly used in many media, is better than that of ordinary 316L austenitic stainless steel, while super duplex stainless steel has extremely high corrosion resistance. In some media, such as acetic acid, formic acid, etc., it can even replace high-alloy austenitic stainless steel and even corrosion-resistant alloys. (4) It has good local corrosion resistance. Compared with austenitic stainless steel with the same alloy content, its wear corrosion resistance and fatigue corrosion resistance are better than austenitic stainless steel. (5) The linear expansion coefficient is lower than that of austenitic stainless steel and close to that of carbon steel. It is suitable for connection with carbon steel and has important engineering significance, such as the production of composite plates or linings. (6) No matter under dynamic or static load conditions, it has higher energy absorption capacity than austenitic stainless steel. This structural part can cope with unexpected accidents such as collisions, explosions, etc. Duplex stainless steel has obvious advantages and has practical application value. Compared with austenitic stainless steel, the disadvantages of duplex stainless steel are as follows: (1) The universality and versatility of applications are not as good as austenitic stainless steel. For example, its use temperature must be controlled below 250 degrees Celsius. (2) Its plastic toughness is lower than that of austenitic stainless steel, and its cold and hot processing technology and forming performance are not as good as austenitic stainless steel. (3) There is a medium-temperature brittle zone, and the process system of heat treatment and welding needs to be strictly controlled to avoid the appearance of harmful phases and damage to performance. 2. Compared with ferritic stainless steel, the advantages of duplex stainless steel are as follows: (1) The comprehensive mechanical properties are better than those of ferritic stainless steel, especially the plasticity and toughness, and are not as sensitive to brittleness as ferritic stainless steel. (2) In addition to stress corrosion resistance, other local corrosion resistance properties are better than ferritic stainless steel. (3) Cold working process performance and cold forming performance are far superior to ferritic stainless steel. (4) The welding performance is also much better than that of ferritic stainless steel. Generally, no preheating is required before welding, and no heat treatment is required after welding. (5) The application range is wider than that of ferritic stainless steel. Compared with ferritic stainless steel, the disadvantages of duplex stainless steel are as follows: The content of alloying elements is high and the price is relatively high. Generally, ferrite does not contain nickel. To sum up, we can summarize the performance and process performance of DSS. It has won the favor of users with its superior mechanical and corrosion resistance comprehensive properties, and has become an excellent corrosion-resistant engineering material that saves both weight and investment.

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Thank you~ But I still hope to learn more about the anti-Cl performance of this material, that is, how many ppm of chloride ions can it work in an environment.