Materials Science Forum, Vol.299, 364-370, 1999
Workability of cold forged powder steel
Powder forging involves axial compression of powder preforms to develop full density and to achieve the desired part shape. The process is generally carried out in a trap die consisting of a through-hole die cavity, a movable upper punch for load application and a lower punch for ejection of the part. Trap die tooling can be used because of the tight control of powder mass. In contrast, conventional forging practice uses moving die halves with flashes gutter to accommodate the variation of material mass in the starting billets. A major contribution to final propel-ties of a powder forging is the way metal flows in reaching full density. Deformation involving extensive shearing causes collapsed pore surfaces to elongate and rub across each other, forming bonds stronger than in pores that just have collapsed with no relative surface motion or elongation This work focus on some basic aspects in powder forging, such as characteristics. variables, advantages, and some examples of successful applications of this process. Sintered parts of Ancorsteel 4600 V steel were cold forged with different levels of deformation and subsequent heat treatments were tested. Metalographies forged densities and mechanical properties of these samples were analyzed. This paper must be understood as a contribution to the development of sintered forging as a process economically viable to the production of parts to the industry.
Keywords:P/M