The stainless steel flange requires NACE treatment, which means that the flange needs to meet the requirements of NACE standards. NACE (National Association of Corrosion Engineers) is a globally recognized professional authority in the field of corrosion control, established in 1943, with the aim of providing technical training, certification programs, industry standards, technical reports, and other services. The NACE standard is a non mandatory guideline established by its technical committee for the field of corrosion prevention and control, widely used to evaluate and manage the corrosion resistance performance of materials.

PREN value requirement: For A182 F51 duplex steel flange, in NACE environment, its PREN value (Pitch Resistance Equivalent Number) must be greater than or equal to 34. PREN value is an important material indicator used to measure the corrosion resistance of materials.

NACE MR0175 standard: This is a specification that covers oil and gas production, refining, chemical manufacturing, and other fields, detailing the conditions and requirements for the use of materials in highly corrosive and high stress environments. A182 F51 duplex steel flange must meet the stress conditions in NACE MR0175 standard during use.