Finite element modelling of PM surface densification process

Abstract

The developments in the field of powder metallurgy (PM) enable production of complex shapes in a cost competitive way especially for automotive industry. Surface densification of sintered gears through a rolling process is a very promising technology, which enables densification of critically stressed surfaces and eventually better mechanical properties. This paper describes the complex forming behaviour of PM gear teeth during surface densification with help to finite element modelling (FEM)

Plasticity Modelling in PM Steels

“…7.1 g/cm 3 and b. 7.3 g/cm 3 Fig . 4 summarizes the two calibrated curves and the tensile curve obtained from HIP:ed test bars.…”

“…Tensile curves, with calibrated matrix materials for density levels of a. 7.1 g/cm 3 and b. 7.3 g/cm 3 Fig .…”

“…Also, the HIP:ed material shows a significantly harder material compared to the calibrated curves. For the simulations the hardening behavior for =7.1 g/cm 3 will be used, as well as the HIP:ed curve. …”

“…For the results presented here, a stell ball with a diamter of 15 mm was pressed with 5 kN onto the surface of a bar with dimensions 120×30×30 mm 3 made of PM steels with densities of 7.1 and 7.2 g/cm 3 . After the tests the indentation mark was measured using a profilometer, giving the depth of the indent as a function of the distance from the centre.…”

“…By applying advanced material modelling as a supplement to experiments, it is often possible to shorten lead times during development considerably. One example is surface densification of sintered gears through gear rolling, see for instance [1][2][3]. By using finite element simulations it is possible to simulate the process and optimize for instance the tool geometry or the material stock on the work pieces.…”