The body of a stainless steel pressure cooker is typically made from food-grade 304 or 316 stainless steel-materials prized for their corrosion resistance, high-temperature tolerance, and ease of cleaning. 304 stainless steel contains 18% chromium (Cr) and 8% nickel (Ni), offering resistance to mild corrosive agents (such as air and steam) at room temperature; 316 stainless steel, meanwhile, incorporates an additional 2–3% molybdenum (Mo) for superior resistance to pitting corrosion, making it ideal for use in coastal or high-salinity environments. Wall thickness directly determines pressure-bearing capacity; industry standards mandate a minimum thickness of 2.5 mm, with some high-end models reaching 4 mm, enabling them to withstand pressures of 1.5 to 2 times atmospheric pressure (approximately 150–200 kPa).
The sealing mechanism is a critical component of the pressure cooker; modern designs typically utilize a silicone sealing ring paired with an automatic locking system. The silicone must meet FDA standards and withstand temperatures ranging from -60°C to 250°C, while also maintaining high elastic recovery (≥85%) to prevent aging and air leaks. The automatic locking system employs a mechanical linkage to ensure pressure is released before the lid can be opened, thereby eliminating safety risks associated with human error. Some brands also incorporate an explosion-proof valve on the lid rim; should internal pressure exceed safe limits, this valve ruptures to release pressure, preventing the cooker body from exploding.
