Metal-elastomer coated steel sheets are core raw materials for producing automotive and industrial flat gaskets. NBR-coated steel and FKM-coated steel are two widely adopted composite substrates, with clear gaps in performance and applicable scenarios.

NBR (Nitrile Butadiene Rubber) coated steel serves as the economical mainstream solution. Its continuous service temperature ranges from -20 °C to 120 °C. It performs well with mineral oil, coolant and diesel, making it ideal for valve cover gaskets, oil pan gaskets and general hydraulic sealing. However, NBR suffers limited resistance to high temperature, ethanol-blended fuels and ozone.

FKM (Fluoroelastomer) coated steel represents high-performance sealing material. It supports continuous operation between -25 °C and 230 °C and withstands gasoline, E10/E85 fuels, synthetic lubricants and long-term thermal cycling. Thanks to low compression set, excellent chemical and ageing resistance, FKM-coated steel is widely used for turbocharger gaskets, fuel system seals and heavy-duty engine gaskets working above 130 °C. The main disadvantage lies in higher raw material and processing costs.

In brief, material selection depends on working temperature, contacting media and service requirements. NBR-coated steel fits conventional moderate-temperature sealing projects, while FKM-coated steel is specified for severe, high-temperature and aggressive fluid environments. Proper substrate selection effectively avoids gasket swelling, hardening and unexpected leakage.