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Tailoring the surface microstructure of starch consolidated vanadium-rich high speed steel powder

Henrik Borgström (Institutionen för material- och tillverkningsteknik, Yt- och mikrostrukturteknik) ; P. Harlin ; Lars Nyborg (Institutionen för material- och tillverkningsteknik, Yt- och mikrostrukturteknik)
European International Powder Metallurgy Congress and Exhibition, Euro PM 2008; Mannheim; Germany; 29 September 2008 through 1 October 2008 Vol. 3 (2008), p. 289-294.
[Konferensbidrag, refereegranskat]

The nitrogen sintering of vanadium rich high speed steel has been applied for tailoring of surface microstructure. The approach has been facilitated by thermodynamics modelling of phase equilibria, novel shaping methods like starch consolidation and various manipulations of the sintering atmosphere. It is demonstrated that elevated nitrogen sintering densification occurs when an open pore structure interacts with nitrogen slightly below the nitrogen-reduced solidus temperature. The compact can then first be pre-sintered to around 85% relative density in vacuum, and thereafter be infiltrated with nitrogen at the nitrogen-reduced solidus temperature and finally be sintered to near full density at a temperature of 10% liquid phase formation in nitrogen. The end result is a microstructure with an elevated MX transformation in the surface, whose depth depends on the carbon balance of the material.

Nyckelord: High speed steel and starch consolidation; Liquid phase sintering; Nitrogen sintering; Vanadium



Denna post skapades 2018-01-03.
CPL Pubid: 254262

 

Institutioner (Chalmers)

Institutionen för material- och tillverkningsteknik, Yt- och mikrostrukturteknik (2005-2017)

Ämnesområden

Materialteknik

Chalmers infrastruktur