| 摘要 |
<p>1,068,724. Making bearings; altering physical properties. AUTOMOBILES BERLIET and HYDROMECANIQUE ET FROTTEMENT. June 9, 1965 [July 22, 1964], No. 24365/65. Headings B3A and B3V. A method of treating the bearing surfaces of metal parts comprises the steps of machining the surface in such a manner that the predominant direction of the machining marks is perpendicular to direction of rubbing of the bearing when in use, heat treating the surface to introduce a non-metallic substance or transition metal into the surface and finally work hardening the surface with rollers. As described the surface is preferably machined to a roughness of 2À5 to 3 microns and the surface treated in a salt bath or gaseous atmosphere to introduce nitrogen, sulphur, selenium or tellurium. Two treatments may be given to introduce consecutively sulphur and nitrogen. As well as work hardening the surface the rolling is stated to have the effect of causing nitride rodlets precipitated from the metal to revert to a state of solution.</p> |
