Numbering and representation of steel
① International chemical element symbols and national symbols are used to represent chemical composition, and Arabic letters are used to represent component content: For example: China, Russia 12CrNi3A ② Use fixed digit numbers to represent steel series or numbers; For example, the United States, Japan, 300 series, 400 series and 200 series. ③ The serial number is composed of Latin letters and order, which only indicates the purpose.International stainless steel marking method
The American Iron and Steel Institute uses three digits to mark various standards Quasi malleable. Of which: ① Austenitic stainless steel is indicated by numbers of 200 and 300 series, ② Ferritic and martensitic stainless steels are represented by 400 series numbers. For example, some of the more common austenitic stainless steels Marked 201, 304L, 316 and 310, ③ Ferritic stainless steel is marked with 430 and 446, and martensitic stainless steel is marked with 410, 420 and 440C Note, duplex (austenite ferrite), ④ Stainless steel, precipitation hardening stainless steel and high alloy with iron content less than 50% usually adopt patent name or trade name.Chinese
Application, Chinese Pinyin, open hearth steel: P, boiling steel: F, killed steel: B, class a steel: A, T8: te8 GCr15: Ball ◆ bonded steel and spring steel, such as 20CrMnTi 60simn, (C content is expressed in ten thousandths) ◆ stainless steel and alloy tool steel (C content is expressed in thousandths), such as 1 thousandth of 1Cr18Ni9 (i.e 0.1% C), stainless C ≤ 0.08%, such as 0Cr18Ni9, ultra-low carbon C ≤ 0.03%, such as 0cr17ni13mo Weight per meter of 304L stainless steel pipe = outer diameter - wall thickness x wall thickness x0.02491 Element content of 304L stainless steel pipe c ≤ 0.03, ni8.00 ~ 12.00, cr18.00 ~ 20.00, Mn < = 2.0, Si < = 1.0, s < = 0.030, P < = 0.035. 304L stainless steel pipe 18cr-8ni-low carbon as Low-C 304 steel, its corrosion resistance is similar to 304 steel in general, but its grain boundary corrosion resistance is excellent after welding or stress relief; It can also maintain good corrosion resistance without heat treatment, and the service temperature is - 196 ℃ ~ 800 ℃. It is applied to outdoor machines in chemical, coal and petroleum industries with high requirements for grain boundary corrosion resistance, heat-resistant parts of building materials and parts with difficulty in heat treatment. Purpose: mainly used for direct drinking water engineering and other fluid transportation with high requirements Main features: long service life; Low failure rate and water leakage rate; The conveying water quality is good, and no harmful objects will be precipitated into the water; The inner wall of the pipe is smooth and has low water conveyance resistance; High cost performance, service life up to 100 years, no maintenance and low cost; It can withstand high water flow rate erosion of more than 30m / S; Exposed pipe laying and beautiful appearance.Tube for food hygiene
Uses: milk and food industry, pharmaceutical industry, industries with special inner surface requirements. Process features: internal weld bead leveling treatment, solid solution treatment, internal surface electrolytic polishing. Performance features: the inner surface roughness Ra is more than 0.2, the wall hanging residue is small, easy to clean, prevent bacterial growth, electrolytic polishing has passivation effect, and the inner wall has good defense performance. Test methods: horizontal, longitudinal flattening, reverse flattening, hydrostatic test or eddy current flaw detection, mechanical property test, inner surface roughness test.