FR2559162A1 - Process for recharging metal moulds used for forming or stamping components - Google Patents

Abstract

Process for recharging metal moulds used for forming or stamping components by spraying a fine powder optionally composed of a mixture of powders at a high speed (of the order of Mach 6) and at a relatively low temperature (between 2700 and 3000 degrees). In addition to a perfect adhesiveness to the base material, this method offers numerous technical and economic advantages.

Description

 The manufacture of the parts necessary for the development of a mechanical assembly includes a significant part of modeling and stamping, operations which require the use of very often metal molds.

 These molds degrade fairly quickly due to tears and the appearance of defective geometry, so to reduce these defects they are made.

generally in materials, metallic or not, resistant well to the causes leading to their setting. out of service, for example, steels that withstand shocks well even at high tompératuras; sometimes even in spite of the significant price supplement it is advantageous to have recourse to materials such as tungsten carbide which give the parts a surface which improves everything. allowing. to make larger series of correct parts.

 The expense thus made for the molds is very high, so we have tried to extend the duration of these by recharging them, an operation which until now has not given satisfactory results.

 The present invention provides a satisfactory solution to the problem of recharging, including a last attempt. consisted of the projection of t; UnQ powder. carbide e.

tungsten with a fairly firm particle size at a mach 2 speed; this powder. was brought to a minimum temperature of 15,000 degrees by the production of an electric arc, that is to say beyond the melting temperature of the carbura. tungsten; the disadvantage encountered with this method has been to ensure that insufficient adhesion to the base material.

 The present invention is characterized by the projection at a temperature between 2,700 and 3,000 degrees and at a speed of the order of mach 6 of a fine powder of a filler metal or a metal carbide, by example of tungsten carbide.

 This temperature and this high speed make it possible to project fine droplets which take on a "pasty" state upon contact with the base material, the temperature of which is. normal.

 It may be advantageous to add to the powder a small proportion of powder facilitating adhesion to the base material, for example a small amount of cobalt powder to the powder of tungsten carbide or nickel.

 your high speed and temperature are obtained by methods derived from those used for rocket propulsion.

 The projection can be made from a water-cooled spray gun, inside which the reaction of oxygen with hydrogen or with propane takes place.

 This method also offers the possibility of having a tolerance of several centimeters between the end of the "nozzle" of the gun and the part to be reloaded which can thus have the most complicated shapes.

The advantages of this invention. are: - better surface condition of. rooms. produced, - greatly increased mold life, - possibility of satisfactorily
relatively large thicknesses of filler metal
aunt (several millimeters), - very low porosity of the layer. contribution, - costs due to 1 t mold maintenance
diminished.

Claims (2)

R E V E N D I C A T I O N S 1- Method of reloading the molds used, in particular, for formatting and forging. parts, characterized by the projection of fine powders at a very high speed of the order of mach 6., and - at a relatively low temperature, of the order of 2.700 to 3.000 degrees. 2- Refill procedures for the molds used, in particular, for formatting and forging. pi case according to claim 1, characterized by the use of fine tungsten carbide powder mixed with a small amount of cobalt or nickel powder in order to obtain perfect adhesion.