Creusot-loire

Nitruvid

Chavanne-ketin

Robert Leveque

Andre Rambert

Joseph J Terrasse

Michel Seux

Anne L Pichat Nec Nedelec

Louis M Rabbe

Marc Robelet

Jean F Rieu

Claude Chabrol

A process for reducing the coefficient of friction and the wear between a metal part and an organic polymer- or copolymer-based part, in an aqueous medium containing chlorides, characterized in that the organic polymer- or copolymer-based part is submitted to a surface treatment by ionic implantation of elements selected from nitrogen, argon, oxygen and carbon.

Process for reducing the coefficient of friction and wear between a

The roll is made from a low alloy steel having the following composition by weight : C: 0.76 to 0.92; Mn: 0.70 to 1.40; Si: 0.70 to 1.40; S.ltoreq.0.020; P.ltoreq.0.025; Ni.ltoreq.0.60; Cr: 1.50 to 2.20; Mo: 0.15 to 0.55; V: 0.08 to 0.25; Cu.ltoreq.0.50; the remainder being iron and accidental impurities.

Forged cold-rolling roll

A process for the chromization by gas of steels containing more than 0.2% of carbon, consisting of three successive treatments, the chromization treatment proper employing a cement having a ferrochrome base containing between 1% and 3% of carbon, and preferably 2%. The process is particularly useful in the chromization of structural and tool steels.

Chromization of steels by gas process

The object of the present invention is an improvement in chromizing methods, constituted by a method of chromizing steels to a depth e greater than 30 microns, usable for steels with a carbon content of at least 0.2%, especially for steels for construction work and steels for tools, characterized by the combination of three successive treatments, the first of these three treatments consisting of an ionic nitriding of a surface layer between 100 and 350 microns thick, this ionic nitriding being realized in an atmosphere constituted by a mixture of nitrogen and hydrogen, at a temperature of between 450.degree. C. and 650.degree. C., for between 5 and 40 hours, so as to obtain between 1.5% and 2.5% nitrogen in the nitrided layer, the second of these treatments consisting of a chromizing by gaseous method forming chromium carbides, lasting between 5 and 30 hours, and realized at temperatures of between 850.degree. C. and 1,100.degree. C., the third of these three treatments being a thermal treatment comprising a quenching in oil of the chromized piece followed by a tempering at a temperature of between 600.degree. C. and 650.degree. C., lasting between 30 minutes and 10 hours, depending on the size of the piece treated.

Chromizing of steels by gaseous method

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Firminy, France

Robert Leveque