Patent 4414286 Issued on November 8, 1983. Estimated Expiration Date: May 26, 2001. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
428/616, Deflectable by temperature change (e.g., thermostat element)228/235.2, Roll bonding374/57, Of susceptibility to thermally induced deteriouration, flaw, or failure374/7, Thickness, erosion, or deposition428/617, More than two components428/619, Both components Fe-based with more than 10% Ni428/679, Co- or Ni-base component next to Fe-base component428/685, Containing more than 10% nonferrous elements (e.g., high alloy, stainless)428/940Pressure bonding (e.g., explosive, etc.)
A composite thermostat metal having layers of metal of relatively high and relatively low coefficients of thermal expansion metallurgically bonded together has a relatively thin, corrosion-resistant layer of an austenitic stainless steel metallurgically bonded to the low expansion side of the thermostat metal, the stainless steel material being selected from the group consisting of austenitic stainless steels which undergo austenite to martensite transformation and concomitant lowering of coefficient of thermal expansion during work hardening. The stainless steel material is work hardened to a selected extent for lowering its coefficient of thermal expansion so that it cooperates with the other components of the thermostat metal in providing the thermostat metal with suitably high flexivity while also providing improved corrosion-resistance properties on the low expansion side of the thermostat metal. In one embodiment, the thermostat metal embodies a second layer of austenitic stainless steel at the opposite or high expansion side of the thermostat metal, the second layer material being selected from the group consisting of austenitic stainless steels which are characterized by relatively high coefficient of thermal expansion and are substantially free of austenite to martensite transformation during work hardening, whereby the second layer also cooperates in achieving a desired high flexivity while providing corrosion resistance properties for the high expansion side of the thermostat metal.
Peckner, D. et al., Handbook of Stainless Steels, McGraw Hill Book Co., pp. 1-6 to 9, 4-28 to 35, 12-22 to 26, 19-2 and 3, A1-54 and 55 (1977)