Showing papers on "Austempering published in 1980"
Patent•
8 Mar 1980
TL;DR: In this paper, the vibration isolating semispherical graphite cast iron with excellent vibration absorbing capacity and strength obtained by a method wherein a shape of a graphite crystal is formed to an intermediate shape of spherical and a flake like forms as well as the graphite with a carbon eq. of a specific value or more is subjected to austempering treatment.
Abstract: PURPOSE: To provide the vibration isolating semispherical graphite cast iron with excellent vibration absorbing capacity and strength obtained by a method wherein a shape of a graphite crystal is formed to an intermediate shape of a spherical and a flake like forms as well as the graphite cast iron with a carbon eq. of a specific value or more is subjected to austempering treatment. CONSTITUTION: The semispherical graphite cast iron containing, in a wt% basis, 3.0W4.1% C, 1.5W40% Si, 4.3% or more carbon eq. (C+1/3 Si) and 0.01W 0.08% Mg is subjected to the austempering treatment. That is, the aforementioned semispherical graphite cast iron is heated at 920°C for 2hr. in an austenite range and, thereafter, subjected to isothermal transformation in a salt with a temp. of 240W360°C to convert a substrate texture to a Bainite texture. As the result, the objective vibration isolating graphite cast iron having a spheroidization ratio of 35W 70%, containing 7W15% graphite in an area ratio and comprising a Bainite texture of which a substrate texture has 10W40% residual austenite in an area ratio is obtained. COPYRIGHT: (C)1981,JPO&Japio
4 citations
Patent•
23 Oct 1980
TL;DR: In this paper, the increase in size of the grains of workpieces heated to above the austempering point Ac3 for forming into springs, which occurs otherwise, is prevented by direct, electrical resistance heating during a maximum of 150 s.
Abstract: The increase in size of the grains of workpieces heated to above the austempering point Ac3 for forming into springs, which occurs otherwise, is prevented The workpieces are raised at the most to a temp of Ac3+10 degrees C, and this heating is effected by direct, electrical resistance heating during a maximum of 150 s The workpieces are then coiled and cooled Pref the heating is performed cyclically The cooling is carried out according to tempering technology After cooling off the workpieces are stress relieved by shockwise, direct, electrical resistance heating Overcomes the problems of the increase in size of the austenite grains at the surface, which tends to take place whilst the interior of the metal is approaching the required temp Oxidn and decarbonising are also prevented and the improved surface structure improves considerably the characteristics of the springs and lengthens their lifetime, paraffin wax, an alkoxylated carboxylic acid or a cholesterol carboxylic acid ester Typical flux components are halides of Zn, Sn or NH4 or hydrazine hydroxide Suitable thermoplastic fluxes are rosin, or satd (hydroxy)carboxylic acids
2 citations