Corrosive service ball valves
Corrosion is a gradual material loss due to chemical or physical reaction with the process fluid; based on the concentration, temperature and pressure fall, exposed fluid surfaces can cause severe damage to the valve efficiency unless the right sort of valve and equipment are chosen.
Aggressive contaminants or solid particles may be present in the process fluid typically identified as corrosive & dirty applications.
Sulfuric acid (H2SO4), chlorides, moist acid gas (with carbon dioxide, CO2) and dry sour gas (with hydrogen sulphide, H2S) are all corrosive process ingredients.
Corrosion-resistant alloy (CRA) products, overlays or PTFE layer (Halar layer) on exposed stress bearing and maintaining parts should be regarded to avoid valve continuity and minimize the likelihood of failure and leakage. Source materials (Hydrogen Sulphide, H2S) should also comply with NACE MR0175 (ISO 15156) or NACE MR0103 when indicated for pipeline.
High Alloys, Nickel Alloys, Duplex (22Cr – 2 Ni) and Superduplex (25 Cr – 5 Ni) can be supplied according to corrosion resistance requirements as per special material standards (i.e. Norsok MDS D46 and D44 for Duplex, D56 and D54 for Superduplex, or similar standards).
In addition Electroless Nickel Plating (ENP) and 316L SS or Alloy 625 weld overlay are frequently used to enhance corrosion resistance of balls, seats, stems, seat pockets and stem sealing areas, in corrosive service.
Special designs for abrasive mediums, slurry, scaling, fouling and solidifying facilities are included in the our valve range.