For composite tube sheets, is intergranular corrosion a concern?
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Example: For the tube side of the heat exchanger, the 904L material requires testing for intergranular corrosion as well as re-testing of its properties; the tube sheet is made of 904L+S30408. According to code requirement 2.1.2.1(4), “......and verification testing of the chemical composition and mechanical properties of the materials used in the main pressure-bearing components......” Can it be understood that the layered structure of the tube sheet does not require re-testing, but intergranular corrosion testing is still necessary?
Based on the information you provided, it can be understood that the main material of the pressure-bearing components in the composite tube sheet is 904L, and verification tests for its chemical composition and mechanical properties are required. Furthermore, depending on the material, intergranular corrosion may be necessary. Therefore, in specific cases, it is necessary to determine whether intergranular corrosion prevention is required based on the requirements of the tube sheet material and the operating environment. .
Standard 3.2.4, Subsection 3.2.4.2: Preparation of specimens for corrosion resistance testing. Standard 3.2.7: Special corrosion requirements. For pressure vessels or pressure components with special corrosion requirements, such as those prone to intergranular corrosion, appropriate corrosion resistance measures, testing methods, and other technical requirements shall be specified in the design documents.
If the tube sheet cladding is not taken into account in the tube sheet strength calculations, then it is sufficient for the cladding to resist intergranular corrosion only
If the technical requirements in the design drawings state that \"the intergranular corrosion sensitivity testing of the stainless steel material used for the pipe sections and the weld joint specimens shall comply with GB/T21433.....GB/T4334...\\", and the material specification sheet indicates that the material is suitable for use against intergranular corrosion, can it be assumed that it is sufficient to conduct intergranular corrosion testing only on the weld joint specimens?
Materials using foreign brand names must be handled in accordance with the requirements of Clause 2.1.2.1(4) of the regulations
Is it correct not to choose overseas materials for 904L?