JPS56144817A - Lubricated hot extruding method for alloy-steel, steel, and heat-resisting alloy - Google Patents

Abstract

PURPOSE: To keep a uniform glass layer at performing the lubricated hot extrusion in order to smooth the extrusion work, and to improve the productivity and economy, by mixing a prescribed glass powder and a prescribed reaction retarder in a prescribed proportion, and by coating the surface of the blank material with this mixture in a prescribed thickness.

CONSTITUTION: A 100pts.wt. powder glass whose viscosity is 10^1.5W10^4.0 poise at the working temperature region and the largest particle size is ≤50μm, and a 5W50pts.wt. reaction retarder which comprises such metal oxides as silica, alumina, titania, and one kind or two or more kinds of aluminum phosphate as the metal phosphate whose largest particle size is ≤20μm, are mixed together to prepare a hot glass lubricant. With this glass lubricant the surface of the blank material is coated in thickness 50W200μm; thereafter, the blank material is subjected to the hot extrusion work. The reason of prescribing the viscosity and particle size of the said powder glass is as follows; if the viscosity is lower than the prescribed value, the glass coat drips away from the surface, and if the viscosity is higher than the prescribed value, the lubricity becomes worse, and if the particle size is ≥50μ, uniform coating film is not formed. The reason of prescribing the particle size of the said reaction retarder is because of necessity of compactly coating the glass particles. As for the mixing proportion, if the reaction retarder is ≤5pts.wt., uniform coating film is not formed, and if it is ≥50pts.wt., the viscosity becomes too high so that the lubricating effect becomes worse.

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