Heating foils - Import export

HPM® 80/20 A is a resistance alloy used in electric heating applications. It is recommended for use in dry air applications up to 2150°F with good hot strength. Such as, flexible metal foil heaters and airbag igniters. The alloy forms rather well and has good welding characteristic. Caution should be used to avoid extended exposure to elevated temperature in marginally oxidizing or partially reducing atmospheres as it would be susceptible to “green rot” corrosion, carburization and sulfurization. Available Sizes: HPM® 80/20 A is available from Hamilton Precision Metals as strip product in thicknesses from 0.0005” to 0.050” (0.0127 mm to 1.27 mm) and width up to 12” (304.8 mm). The material conforms to ASTM B-344. Foil product may be supplied in thickness to 0.0001” (0.00254 mm) in width up to 4.0” (101.6 mm).

Constantan® is a copper-nickel alloy that contains specific minor amounts of additional elements to achieve precise values for the temperature coefficient of resistivity. Careful control of melting and conversion practices results in a very low level of pinholes at ultra-thin thicknesses. The alloy is used extensively for foil resistors and strain gauges. The TCR can be adjusted from the furnished cold rolled values by using a low temperature heat treatment to achieve compensation for all types of spring elements. The foil is normally supplied with 90% cold reduction and a smooth bright surface. The foil is reasonably flat at 4” wide and nearly free of pinholes. The cold rolled foil can be produced with a TCR between +10 to –35 PPM/°C. The heat treatment will shift the foil TCR to the desired value. A typical heat-treat curve for Constantan® shows decreasing resistivity but increasing TCR with increased heat-treating temperature.