What are the uses of ferritic stainless steel?

This post was last edited by fhtube on 2016-7-10 at 10:59. Ferritic stainless steels are widely used; in the field of pipes, the ones I’m aware of include 0CR13 (410s)/1CR13 (410)/2CR13 (420)/3CR13 (420J2)/0CR13SIAL (405)/1Cr17 (430)/022Cr18Ti (439)/019Cr19Mo2NbTi (444)/16Cr25N (446)/00Cr27Mo3Ni2TiNb (44660)/14Cr17Ni2 (431)/0CR13NI5MO (13Cr110), etc. Some of these have a martensitic structure or a semi-martensitic structure. The martensitic structure is generally used in many mechanical parts, such as bearings and oil casing made of materials like 2CR13/3CR13/13CR110; whereas grades such as 0Cr13Al and 1Cr13 are mostly used in air heat exchangers and petroleum refining equipment. 022cr18ti/019cr19mo2nbti is generally used for parts or pipes in water heaters, and it is also used in automotive exhaust systems. 16cr25n is primarily used in air heat exchangers; it can withstand temperatures as high as 1100 degrees, and is commonly used in power plants and steel mills. The material 00cr27mo3ni2tinb is known abroad by the designation S44660; it is an exclusive proprietary product of Plymouth. It is used in nuclear power plants, desalination facilities, and power plant condensers. At present, they only produce welded tubes. According to foreign sources, this material can serve as a substitute for titanium. In China, there is also a company in Jiangsu that produces seamless tubes at quite competitive prices. Ferritic and martensitic stainless steels are widely used abroad, but in our country, due to certain systemic issues, monopolies, and a tendency among people to settle for the status quo, their widespread adoption has not been possible. In fact, these materials offer better corrosion resistance and physical properties in certain applications compared to other austenitic or duplex steels, as well as nickel-based alloys. This is also why many of our materials can be produced domestically, yet we are willing to pay a high price to import them from abroad:D. These are my modest insights on this topic, and I hope everyone will actively participate in the discussion. :lol

This post was last edited by fhtube on 2016-7-10 at 10:49. Processing techniques for ferritic stainless steel: 1. Cold-rolled steel pipes exhibit a certain degree of work hardening, have a fine grain structure, and a dense and uniform microstructure; after heat treatment and quenching, they possess good impact toughness. Current processing methods allow for good ductility, though the price of such pipes is relatively high. 2. The surface after cold rolling and drawing has no oxide scale, ensuring good quality ； 3. Products manufactured through cold deformation have high dimensional accuracy and good surface quality ； Hot rolling: This is in contrast to cold rolling; cold rolling takes place below the recrystallization temperature, while hot rolling occurs above that temperature. Its characteristics: 1. Poor toughness and surface smoothness, lower price ； 2. The temperature for hot rolling is similar to that for forging ； 3. The heat pipes are manufactured by hot rolling; their surfaces have oxide scales, and the dimensional tolerances are relatively large ； 4. Due to its production process, it is more commonly used in civilian applications. 5. Hot-rolled steel pipes have mechanical properties that are far inferior to those of cold-worked pipes, and are also lower than those of forged pipes.

It seems like I’m off-topic; this question is about ferritic stainless steel, not martensitic stainless steel

This post was last edited by fhtube on 2016-7-11 09:22. 0CR13SIAL (405)/1Cr17 (430)/022Cr18Ti (439)/019Cr19Mo2NbTi (444)/16Cr25N (446)/00Cr27Mo3Ni2TiNb (44660) – these all belong to ferritic stainless steels. The characteristic of ferritic stainless steels is that chromium is their main element; it determines the structure and properties of the steel, having a significant impact on its mechanical properties and resistance to corrosion. The microstructure of ferritic stainless steel is ferrite, which determines that its mechanical properties are characterized by low strength and poor plasticity during further processing, such as welding cracks. An increase in chromium content can improve the corrosion resistance of ferritic stainless steels. Ferritic stainless steels are mainly suitable for oxidizing media, and they have poor corrosion resistance in reducing media. Its resistance to stress corrosion cracking in media containing nitrides is one of its most notable features; it is even better than that of chromium and nickel austenitic stainless steels. However, pitting corrosion and intergranular corrosion can lead to stress corrosion cracking. Ferritic stainless steels are sensitive to intergranular abrasion, pitting abrasion, and crevice abrasion, but these issues can be mitigated by reducing carbon content and adding molybdenum. (This is a passage I copied from some documents; it’s pretty much what I already know, so I didn’t bother typing it out): lol But with the current processing techniques, if one can properly understand the properties of this material as well as the appropriate heat treatment methods during the steel-making process, it’s possible to avoid issues such as poor surface quality, reduced toughness, and coarse grain structure. For example, the yield strength of TP439 ferritic stainless steel is 280/295 MPa (the standard is 205 MPa minimum), its tensile strength is 460/475 MPa (the standard is 415 MPa minimum), its elongation can reach 30%, and its hardness is HRB78/81 (the standard is HRB90 maximum). Ferritic steels have a high thermal conductivity, a low coefficient of expansion, good oxidation resistance, and particularly excellent resistance to stress corrosion. Therefore, it has a wide range of applications, being used in industries such as home appliances, automobiles, ships, the chemical industry, and oil refining.

Why doesn’t anyone have any other answers? :I hope everyone can discuss this topic. I truly hope that some of the steel mills and downstream enterprises in our country will continue to develop these materials. Abroad, there is strong encouragement for the use of these materials, but in our country we still remain behind in terms of adopting them. :Q