| 摘要 |
PURPOSE:To obtain a shape memory alloy coil spring consisting of an NiTi shape memory alloy excellent in thermal responsibility in a wide range by specifying a composition consisting of Ni and Ti and also specifying initial transformation temp. at the time of cooling and transformation finishing temp., respectively. CONSTITUTION:The NiTi shape memory alloy has a composition which consists of, by weight, 55.0-56.0% Ni and the balance Ti with inevitable impurities and in which a part of the above Ni or Ti is substituted, if necessary, by one or more elements among Co, Fe, V, Cr, Mn, and Al by 0.05-2.0%, and further, relations of Ms<=70 deg.C, Mf>=10 deg.C, and Ms-Mf>=15 deg.C are held between initial transformation temp. Ms deg.C at the time of cooling and transformation finishing temp. Mf deg.C. This NiTi alloy is cold-worked into coil spring at >=30% reduction of area and subjected to shape memory treatment at 400-480 deg.C, by which the shape memory alloy coil spring can be obtained. By using this coil spring, the hot water mixing control valve working at 70-10 deg.C with superior thermal responsibility can be formed. |
