Design of the thixotropic lubricant and its influence on compaction behavior of Cr-alloyed PM steel

Abstract

A multifunctional lubricant containing thixotropic components was designed for Cr-alloyed PM steel. The thixotropic properties of the lubricant components, compaction behavior of the powder mixture and the lubrication effects of the lubricant were explored. The results demonstrate that the thixotropic components in the lubricant are polyethylene wax and polyamide wax. When the compaction pressure increases from 400 MPa to 800 MPa, the polyamide wax content corresponding to the maximum green density increases from 0% to 30%. The thixotropic properties of polyethylene wax and polyamide wax are reflected at low and high pressures, respectively. By the application of new lubricant in binder treatment technology, alloying additives are effectively filled into the pits of iron particles, the apparent density, flowability and compressibility of mixture are much higher than those of other lubrications. When the content of both polyamide wax and polyethylene wax was 20%, the apparent density and flowability reached 3.46 g/cm3 and 34.88 s/50 g, respectively. And the green density of compacts reached 7.18 g/cm3 at 600 MPa and 7.37 g/cm3 at 800 MPa.