【2026 Red Copper Gaskets】Should red copper gaskets used for sealing be in an annealed or quenched state?

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Should the heat treatment state of the copper gasket used for sealing be annealing or quenching? Anodized copper gaskets are standard products widely used in industrial sealing, whereas quenched copper gaskets are rarely mentioned or used in the sealing industry. The core difference between the two stems from fundamental variations in material properties caused by different heat treatment processes. Copper does not undergo allotropic transformations; its \"quenching\" generally refers to rapid cooling after solution treatment, with the aim of obtaining a supersaturated solid solution to prepare for subsequent aging hardening. However, this is not a process used for gasket sealing. Annealing process: Heat red copper above its recrystallization temperature (e.g., 380–680°C), hold it at that temperature for a while, and then cool it slowly (either in a furnace or by air cooling). Primary purpose: to soften the material, eliminate work hardening, and improve plasticity and ductility. Low hardness, with typical values of HB 30~50 (Brinell hardness). It has excellent plasticity/ductility. It is prone to plastic deformation and can effectively fill in the microscopic irregularities on the sealing surface. The sealing mechanism matches perfectly. Sealing relies on the plastic deformation capacity of the gasket to establish an initial seal, and on a certain degree of rebound to adapt to changes in operating conditions. Quenching process: The metal is heated to a high temperature and then rapidly cooled (such as by water cooling or oil cooling). Core purpose: Theoretically, it can increase hardness and strength. Red copper (pure copper) cannot undergo the traditional \"quenching\" process like steel, as it does not possess the conditions necessary for strengthening through martensitic transformation resulting from rapid cooling. However, red copper can be subjected to solution treatment (a rapid cooling process similar to quenching), and its purpose and applications are completely different from those of steel quenching. For pure copper, the main purpose is softening (recrystallization annealing) or preventing grain growth, rather than strengthening. For purple steel, both \"quenching\" and \"annealing\" can achieve the effect of softening the material and improving its sealing performance, but there are differences in the process details and the microscopic changes in the material. Traditional \"quenching\" is commonly used for hardening steel, and is less applied to copper. In the field of sealing, a \"quenched purple steel gasket\" undergoes a solution treatment process that involves \"high-temperature solutioning + rapid cooling\", whereas the traditionally defined \"annealing\" is a process that involves \"slow heating + cooling in the furnace\".