BS ISO 18070:2015 pdf download – Corrosion of metals and alloys — Crevice corrosion formers with disc springs for flat specimens or tubes made from stainless steel 5.1Specimen specifications Both flat specimens and tubes made from stainless steels can be used as specimens in the crevicecorrosion formers specified in this International Standard.The specimen outer surface area shall be atleast 100 cm2. NOTE1 A squared specimen with a centre hole is preferred since the distance between the anode and cathodearea might be critical in solutions with low conductivity. NOTE 2lf an electrode potential is applied, a smaller specimen can be used. 5.1.1 Flat specimens A hole, 7 mm in diameter, shall be drilled in the middle of each specimen. NOTE To hang up of specimen and for electrical connection, a small hole can be drilled at one end of thespecimen. 5.1.2Tubes A hole, 7 mm in diameter, shall be drilled in the middle of the tubes in radial dimension.The hole shallbe drilled at both sides of the tube allowing a bolt to be inserted in the hole without alignment.Thelength of the tubes shall be at least 30 mm. NOTE To hang up of specimen and for electrical connection, a small hole can be drilled at one end of thespecimen. 5.2Surface preparation of the specimens 5.2.1The surface finish shall be as reproducible as possible.Any test surface may be tested but it isrecommended that all surfaces, including cut edges and drilled holes, shall be abraded down to at leastP120 grit paper, according to ISO 6344-3.Care shall be taken to avoid overheating the surface. NOTEultra sonic cleaning after abrading can be used. 5.2.2 After abrading and cleaning, the specimens shall be left in air at a temperature higher than thedew point temperature for at least 24 h before testing, to be able to form a stable oxide. 5.2.3 The specimens shall be cleaned immediately prior to immersion in the solution by degreasing.rinsing in high-purity water with a conductivity less than 1 uS/cm, (ISo 3696, grade 2) followed byethanol or a similar solvent and air drying.After degreasing, care shall be taken not to contaminate thetest surface of the specimens. 6Crevice former and assembly6.1General Both flat specimens and tubular stainless steels can be used as specimens in the crevice corrosionformers specified in this International Standard, see Figure 1 and Figure 2. 6.2Disc springs Disc springs with a linear force versus deflection relationship shall be used. The...

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