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Production of powder metallurgical stainless steel components.

This project aims to improve the mechanical properties, wear
corrosion and resistance of sintered stainless steel
components by careful control of processing parameters and
investigating effects on the powder mixes to reduce porosity

Stainless steel powders work harden very rapidly leading to poor compressibility when manufactured by a powder metallurgy process. The result is a porous structure which gives rise to corrosion and strength problems thereby limiting the use of stainless steel powder components. The proposed partnership will research a number of approaches aimed at overcoming these problems: (i) Employ the use of computer assisted predictions of the alloy chemistry and phase equilibria to tailor novel alloy compositions to improve sinterability and, thereby, mechanical properties and corrosion performance. Potential systems that will be investigated include those involving additions of Si, B, Mo, Ti, Cu, Sn and P to a basic Fe-Cr-Ni alloy. (ii) A further alloy system that will be investigated will involve using a reactive sintering technique which has previously been researched as a means of producing fully dense Fe, Al intermetallics. The use of reactive constituents in the sintering process produces local heating in the powder, giving controlled diffusion rates which results in very low porosity. The implication is to admix Fe+Al+Ni powders to ordinary stainless steel powders as a sintering aid. The use of controlled heating and compression conditions can then be used to minimise porosity. A further benefit to enhance corrosion resistance will be the alumina-rich film that develops on any residual pores. (iii) Investigations on "conventional" powders aimed at improving performance by modifying the sintering parameters, such as atmosphere, temperature and time. The work programme will be broken down into 3 main phases; Phase I - Definition The main activity in this phase will be in the use of the MTDATA software system to enable predictions to be made of phase equilibria that will facilitate liquid phase sintering at temperatures of approximately 1150 deg.C aimed at achieving near full density. In addition, segments of the appropriate diagrams for the reactive sintering system will be derived. Phase II - Implementation The research and development activities will focus on the production of atomised powders of suitably modified compositions, undertaking sintering trials, generating mechanical, corrosion and wear performance data on samples, and using this information to optimise the selection of the alloy compositions and sintering parameters. At this point, case study parts will be manufactured and validated industrially. Phase III - Full Exploitation The ultimate interest of the industrial end-users in the project partnership will be to exploit the developed materials in the market place. This will involve carrying out studies of the manufacturing process on an industrial scale, economics and the analysis of both short-term and long-term markets.
Acronym: 
CORESS
Project ID: 
1 424
Start date: 
01-10-1995
Project Duration: 
90months
Project costs: 
1 750 000.00€
Technological Area: 
Market Area: 

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.