Hot Pressing Technology to Produce Wear-Resistant P/M Structural Materials with Dispersed Solid Inclusions

We have examined the possibility of milling iron, nickel, chromium, high-speed steel, and titanium carbide powders in an attritor (attrition mill) for use in producing carbide steel. The powders were milled to a particle size of 1–3 μm for TiC and 10 μm for metal components. As a rule, such powders and mixture of powders do not flow or form, which makes it impossible to produce blanks for hot pressing by the traditional die pressing method. Shells pressed from iron powders are proposed for forming a blank. We tested techniques for hot pressing dispersed powders into such envelopes. __________ Translated from Poroshkovaya Metallurgiya, Nos. 7–8(444), pp. 43–50, July–August, 2005.     

Milling of Carbide-Steel Powder Components and Their Mixtures in an Attrition Mill

Milling of wear-resistant steel and titanium carbide powders is studied with an attrition mill rotation rate of 980 rpm. The physical and technological properties of powders and particle size are determined. Particle shape and the change in material chemical composition during milling are studied. It is established that steel powder cannot be milled to particle sizes less than 3.6 μm whereas a mixture of steel and titanium carbide can be milled to a fine state (0.3 μm). Powders with a size of about 1 μm neither flow nor are formable. Use of benzene as a milling medium makes it possible to prevent steel powder oxidation, but the carbon content in titanium carbide decreases. During milling of the main part of the charge to a fine state rather large steel particles (up to 50 μm) remain.