Commonly used metal materials include soft iron, aluminum, copper, silver, lead, austenitic stainless steel, and nickel-based alloys such as Monel, Hastelloy, and Inconel. The selection of different metal materials is primarily based on factors such as operating pressure, temperature, and the corrosive nature of the medium. For example, nickel-based alloys can withstand temperatures up to 1040°C and, when made into metal O-rings, can handle pressures up to 280 MPa. Monel alloys exhibit excellent corrosion resistance in seawater, fluorine gas, hydrochloric acid, sulfuric acid, hydrofluoric acid, and their derivatives. Inconel 718 is known for its outstanding heat resistance.
Metal materials can be fabricated into flat, serrated, or corrugated gaskets, as well as into elliptical, octagonal, double-cone rings, and lens gaskets. These types generally require higher sealing loads and have limited compressibility and resilience, making them sensitive to temperature fluctuations. With the advancement of sealing technology, different metal materials can also be combined in innovative designs to create new sealing products and technologies that enhance overall sealing performance. A typical example is the C-ring used in nuclear reactors.