What are the main considerations or key points when purchasing piping materials for GC2?

It depends on the standards chosen during the design phase

Advantage 1: Corrosion resistance – Take a look at the figures; its corrosion resistance is on par with that of S31254 and 254SMO. The PREN value of 2507 super duplex steel is as high as 43. Chemical compositions of commonly used duplex and austenitic stainless steels ——————————————————————————————————— USNP grades Equivalent grades Chemical composition, Wt% ——————————————————————————————————— C Cr Ni Mo N PREN* ——————————————————————————————————— Duplex steel S32304 2304 0.03 23 4.5 - 0.1 25 Duplex steel S31803 2205 0.03 22 5.0 3.2 0.18 35 Duplex steel S32750 2507 0.03 25 7.0 4.0 0.3 43 Stainless steel S30403 304L 0.03 18 8.0 - 0.1 20 Stainless steel S31603 316L 0.03 16 11.0 2.0 0.1 24 Stainless steel S31703 317L 0.03 18 11.0 3.0 0.1 30 ——————————————————————————————————— PREN*: Pitting potential equivalent = %Cr + 3.3%Mo + 16%N Advantage 2: Cost advantage – 7% lower nickel content and 3% lower molybdenum content; with the addition of chromium and 0.3% nitrogen, corrosion resistance comparable to that of 254SMO is achieved. It is particularly important to note the three key characteristics of the N content: 1. A significant increase in corrosion resistance ； 2. Improve material strength ； 3. Stabilizes the austenitic structure, resulting in more uniform properties. Compared to 300 series stainless steels, duplex steels are also more cost-effective, though in a different way; their yield strength is twice that of 300 series stainless steels, which means that the thickness of the steel can be reduced while still withstanding the same load. Due to its high strength, it allows for a reduction in the thickness of the materials used, thereby decreasing the weight of the materials required for the equipment and optimizing costs further. In summary, super duplex steel can **reduce the cost of raw materials, offering better overall cost-performance. Advantage 3: Wear resistance. Due to its high nitrogen content, super duplex steel possesses a yield strength and tensile strength that are up to twice those of ordinary stainless steels; as a result, its wear resistance is significantly higher than that of conventional materials. In some pipes or equipment subject to corrosion and fluid erosion, super duplex steels with high nitrogen and high strength offer a longer service life. Coins have two sides, and materials have advantages and disadvantages. Normal! Super duplex steel 2507 has the following disadvantages: Disadvantage 1: Poor deep drawing properties. The strength of duplex stainless steels is twice that of ordinary austenitic and ferritic stainless steels; their tensile and yield strengths are generally higher as well, but their toughness is somewhat lower than that of austenitic stainless steels. Therefore, this material cannot be used for deep stamping processes, nor can it be employed as a stamping material for applications requiring deep grooves. To achieve better corrosion resistance, materials such as S31254 and higher grades are recommended. Disadvantage 2: High welding requirements. In duplex steel, the base metal typically consists of approximately 50% ferrite and 50% austenite. The equilibrium relationship between ferrite and austenite in welded joints is influenced by both the content of alloying elements in the steel, as well as by the filler metal, the welding heat cycle, and the shielding gas. Due to the effect of N, be vigilant for cracks at the root after welding. For multi-layer welding, attention must also be paid to the inter-layer temperature as well as stress-relief heat treatment required after welding.

Yu always answers in great detail. But generally, during acceptance, what is checked are just the appearance, the certificate of conformity, and the quantity. . . .

:) A manufacturing license is required. . . .

Product certificate of conformity, quality certificate, spectral analysis recheck.

This post was last edited by whr73229880 on 2021-8-24 at 10:37. Oh, thank you. The issue is that the 2507 seamless steel pipes purchased earlier had defects during use; I want to know how it was possible to ensure the quality of the products supplied by verifying the supplier and adhering to technical requirements before making the purchase.