254SMO Super Austenitic Stainless Steel

 　　254SMO super austenitic stainless steel, with German designation 1.4547, UNS designation S31254, and domestic designation 00Cr20Ni18Mo6CuN, is a type of standard six molybdenum alloy steel. This super austenitic stainless steel is developed for environments with halides and acids.

　　The carbon content of 254SMO is very low, which means that the risk of carbide precipitation caused by heating is very low.

　　This steel can still pass the Strauss Test ASTMA262 Practice E method even after one hour of sensitization treatment at 600-1000 degrees Celsius. However, due to the high alloy content of the steel, it is possible for the intermetallic phase of the metal to precipitate at the grain boundaries within the above temperature range. These precipitates do not pose a risk of intergranular corrosion when applied in corrosive media. Therefore, welding can be carried out without intergranular corrosion. The supporting electrode is ENICRMO-3, and the supporting welding wire is ERNICRMMO-3. However, in hot concentrated nitric acid, these precipitates may cause intergranular corrosion in the Heat-affected zone.

　　In solutions containing ions such as chloride, bromide, or iodine, ordinary stainless steel is immediately eroded by localized corrosion in the form of spot corrosion, crevice corrosion, or stress corrosion cracking. However, in some cases, the presence of halides can accelerate uniform corrosion. This is especially true in the presence of halides in non oxidizing acids.

　　In pure sulfuric acid, 254SMO has much greater corrosion resistance than 316L ordinary stainless steel. However, compared with 904L (NO8904) stainless steel at high concentrations, 254SMO has slightly weaker corrosion resistance. In sulfuric acid containing chloride ions, 254SMO has the greatest corrosion resistance. Due to the possibility of localized and uniform corrosion, 316L ordinary stainless steel cannot be used in hydrochloric acid, but 254SMO can be used in diluted hydrochloric acid at normal temperatures. There is no need to worry about point corrosion in the area below the boundary line, but efforts must be made to avoid the presence of gaps.

　　In fluorosilicic acid (H2SiF4) and hydrofluoric acid (HF), the corrosion resistance range of ordinary stainless steel is very limited, while 254SMO can be applied over a wide range of concentrations and temperatures.



评论

发表评论

此博客中的热门博文

Japanese Standard (1)

图片
 　　In the grades of Japanese steel (JIS series), ordinary structural steel mainly consists of three parts to represent the material. 　　For example, S (Steel) represents steel, F (Ferrim) represents iron; The second part represents different shapes, types, and uses, such as P (Plate) for plates, T (Tube) for tubes, and K (Kogu) for tools; The third part represents the characteristic number, which is generally the tensile strength. For example, SS400 represents Steel, the second S represents Structure, 400 represents the lower limit tensile strength of 400MPa, and the overall represents ordinary structural steel with a tensile strength of 400MPa.
阅读全文

National Standard Properties of 304 Stainless Steel Plate

图片
　　 304 stainless steel plate tensile strength (Mpa) 520 　　Yield strength of 304 stainless steel plate (Mpa) 205-210 　　Elongation rate of 304 stainless steel plate (%) 40% 　　304 stainless steel plate hardness HB187 HRB90 HV200 　　The density of 304 stainless steel is 7.93 g/cm3. Austenitic stainless steel generally uses this value. The chromium content (%) of 304 is 17.00 to 19.00, and the nickel content (%) is 8.00 to 10.00304, which is equivalent to 0Cr19Ni9 (0Cr18Ni9) stainless steel in China 　　304 stainless steel is a versatile stainless steel material with stronger rust resistance than the 200 series stainless steel material. It also has good resistance to high temperatures. 　　304 stainless steel has excellent rust resistance and good intergranular corrosion resistance. 　　For oxidizing acids, it was found in experiments that 304 stainless steel has strong corrosion resistance in nitric acid below boiling temperature with a concentration of ≤ 65%. It also has good cor...
阅读全文

Similarities and Differences in Performance between N08367 and N08926

图片
 　　Today, let's talk about the similarities between the two. UNS N08367 and 1.4529 (N08926) materials are both super austenitic stainless steel. High Cr, high Mo, high corrosion resistance, and excellent corrosion resistance in harsh environments such as high-temperature seawater or smoke exhaust desulfurization devices. Under certain conditions, it has corrosion resistance comparable to Hastelloy and pure titanium, making it a cost-effective stainless steel. 　　If the performance is similar, the components must be very similar. 　　I'll show you the ingredient list and you'll know. 　　Except for the Cu element, which has a smaller intersection (0.5-0.75%), all other elements have a larger space, which means that other components can be completely identical. 　　So the two are basically the same and can to some extent replace each other. 　　The commonly used pitting resistance index (PRE) for stainless steel expresses the degree of corrosion resistance. 　　The calcul...
阅读全文