Why is it stipulated in HG2053 that cast iron pressure components cannot be used for toxic gases?
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Why is it stipulated in HG2053 that cast iron pressure components cannot be used for toxic gases?
Cast iron parts have a lower density; although there is no leakage at the time, there is still a risk of leakage over time.
Cast iron has a high carbon content, poor plasticity, uneven microstructure, and poor weldability； Cast iron also has lower tensile strength, plasticity, and toughness compared to carbon steel, and it is a brittle material. Therefore, HG/T20531 \"Cast Steel and Cast Iron Vessels\" stipulates that they shall not be used as pressure-bearing components in pressure vessels intended to hold media with an extremely high, high, or moderate degree of toxicity or flammable media, nor as components in non-pressure vessels with a pressure of 0.05 MPa or higher; they shall also not be used as pressure-bearing components in shell-and-tube waste heat boilers.
Cast iron has a high carbon content, poor plasticity, uneven microstructure, and poor weldability； Cast iron also has lower tensile strength, plasticity, and toughness compared to carbon steel, and it is a brittle material. Therefore, HG/T20531 \"Cast Steel and Cast Iron Vessels\" stipulates that they shall not be used as pressure-bearing components in pressure vessels intended to hold media with an extremely high, high, or moderate degree of toxicity or flammable media, nor as components in non-pressure vessels with a pressure of 0.05 MPa or higher; they shall also not be used as pressure-bearing components in shell-and-tube waste heat boilers.
Why can’t toxic media be used with cast iron
Cast iron has a high carbon content, poor plasticity, uneven microstructure, and poor weldability； Its tensile strength, plasticity, and toughness are also lower than those of carbon steel. Since cast iron is a brittle material, once it fractures, it breaks into fragments, resulting in extremely high destructive force ； If it contains toxic substances, the risk of use will be even greater. Pressure vessels are hazardous devices; materials with high plasticity and high toughness are chosen to ensure safety during use. Therefore, HG/T 20531 \"Cast Steel and Cast Iron Vessels\" stipulates that they shall not be used for pressure vessel components that are intended to hold media with an extremely high, high, or moderate degree of toxicity as well as flammable media, nor for components of non-pressure vessels with a pressure of 0.05 MPa or higher; they also shall not be used for pressure components in shell-and-tube waste heat boilers.