High-strength blackened gasket
High-strength blackened gasket is a gasket that forms a black Fe₃O₄ oxide film on the surface of alloy steel through chemical oxidation (blackening treatment), with a film thickness of about 0.5-1.5μm. Its base material is usually 65 manganese steel or 42CrMo alloy steel, and after quenching + tempering treatment, the hardness can reach HRC35-45.