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Net shape manufacture of steel parts by water-based forming and liquid phase sintering


Objectives and content
Powder Metallurgy (PM) is a cost-effective net-shape
manufacturing technology for mass production of a wide
range of metallic components. The normal PM production
uses relatively coarse powder (broad size range below 150 mm) and involves uniaxial die pressing and sintering.
The size and shape of the final product is largely set by
the pressing. Because of cost of dies and certain
restriction in shape and size, this current PM route is
not suited for small series production of large/complex
PM parts, which limits the exploitation of PM into new
business areas besides the automotive industry. This
project addresses these needs based on the combination of
a novel approach of environmentally friendly, water-based
forming, called Starch Consolidation, and the development
of liquid phase sintering of relatively coarse steel
powder. The intended process includes: preparation of
powder suspension; pouring of this into a mould and
heating to 60-70 C, demoulding and drying of shaped part;
sintering to high density.
The Starch Consolidation only allows powder packing below
60% of theoretical density. An important and difficult
task will therefore be to develop liquid phase sintering
into working technology for large shrinkage ratios
enabling sintered densities above 90%. Industrial needs
also make it important to limit sintering temperature to
below 1150 C, allowing the use of traditional belt
furnaces. The research on novel powder forming and
sintering technologies will here provide opportunities
for net-shape of manufacture of steel parts that cannot
be obtained cost-effectively through any other technique
The research approach will comprise following core
activities: thermodynamical modelling of alloy systems
and compositions; tailored preparation of steel powders;
development and understanding of the forming technique -
Starch Consolidation - based on colloid and surface
science principles; a broad development of knowledge and
practices regarding liquid phase sintering based on three
approaches (mixed, coated and prealloyed powders);
detailed characterisation and understanding of
microstructural development during powder processing,
forming and sintering; theoretical assessment of liquid
phase sintering of coarse powder; assessment of product
measures; industrial sintering verification.
It is foreseen that novel PM technologies in this project
in the future will lead to: reduction of tooling and
powder costs by factors of 20 and 10, new PM product
possibilities, microstructures, properties, product
measures equivalent to those obtained with current PM
processes as well as other manufacturing technologies.

Funding Scheme

CSC - Cost-sharing contracts


Chalmers University of Technology AB
7,Hoeralsvaegen 7
412 96 Göteborg

Participants (4)

Höganäs AB

263 83 Högands
Sintermetal SA
5,Calle Covadonga
08291 Ripollet (Barcelona)
Technische Universität Dresden
01062 Dresden
Universidad Carlos III de Madrid
15,Calle Butarque
28911 Madrid