US 3461506 A
Description (OCR text may contain errors)
Aug. 19, 1969 R E. mcg ETAL 3,461,506
DIE FOR HOTITPRESSING POWDERED METAL I med April 2e. 1967 eo hfarre l yz M law United States Patent O U.S. Cl. 18-47 5 Claims ABSTRACT OF THE DISCLOSURE A die having an inner surface which does not adhere to powdered metal when compressed under high pressure and temperature.
In the use of powdered metal for making articles it is customary to compress the powder in dies under high pressure and temperature. However difculty has been experienced due to the powder sticking to the inner surfaces of the dies even when the dies are made of tungsten carbide. This results not only in imperfect articles but also in rapid deterioration of the dies.
Objects of this invention are to overcome the aforesaid ditiiculty and to provide a die in which there is no tendency to weld, gall or score either the die or the compacted article.
The present invention involves the discovery that titanium carbide is unique in that it affords dies which avoid all tendency to adhere to the compacted articles. The titanium car-bide is preferably bonded with small amounts of nickel or cobalt or both, e.g., to the extent of about 3 to 12 percent by weight.
While the walls of the dies may consist of titanium carbide, the dies would then be unduly costly. Consequently the walls are preferably made of some other material, such as tungsten carbide, and then lined with titanium carbide. This can be done by making a thin liner to fit the die or by vapor disposition in well-known manner.
For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawings in which FIG. 1 is a longitudinal axial section; and
FIG. 2 is an end view.
The particular embodiment chosen for the purpose of illustration comprises a cylinder made of tungsten carbide 3,461,506 Patented Aug. 19, 1969 "ice in three sections 1, 2 and 3 to facilitate finishing the inner surface of the die before the sections are assembled. To hold the sections together the die is wound with Wire 4 having a thermal expansion coefiicient closely matching that of the die, such as tungsten or molybdenum, as disclosed and claimed in the copending application of Richard E. Rice, Sr., No. 633,780, tiled on even date herewith. The inner surfaces of the sections are lined with surfaces 5 of titanium carbide as above described.
In use the powdered metal is compressed between two plungers 6 and 7 in usual manner. To charge the die with powdered metal the upper plunger 6 is Withdrawn as shown in FIG. l, and to expel the compacted article the upper plunger is Withdrawn and the lower plunger is advanced.
It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.
1. For making articles by hot-pressing powdered metal, a die having an inner surface consisting principally of titanium carbide.
2. A die according to claim 1` wherein said surf-ace comprises a liner.
3. A die according to claim 1 wherein said surface comprises a vapor deposition.
4. A die according to claim 1 wherein said surface also comprises nickel or cobalt or both.
5. A die according to claim 3 wherein the body of the die consists of tungsten carbide.
References Cited UNITED STATES PATENTS 3,067,465 12/ 1962 Giardini et al. 3,061,877 11/1962 Custers et al. 3,084,388 4/ 1963 Ballhausen 18-16.5 3,085,291 4/1963 Hals etal 18-16.5 3,088,170 5/ 1963 Strong. 3,213,491 10/1965 Craig. 3,329,513 7/1967 Murata et al 264-332 X I. HOWARD FLINT, JR., Primary Examiner U.S. C1. X.R.