Effects of Austenitisation Temperature and Multiple Tempering on the Microstructure and Impact Toughness of a 5 wt. % Cr Cold Work Tool Steel

Rehan, ArbabHögskolan Väst,Forskningsmiljön produktionsteknik(PTW),Uddeholms AB, SE-683 85, Hagfors, Sweden,PTW (author)

The microstructure and properties of a 5 wt.% Cr cold work tool steel were studied after austenitisation at 1020°C, 1050°C or 1075°C followed by single, double and triple tempering treatments at 525°C. The microstructures were investigated with scanning electron microscopy and X-ray diffraction and phase transformations were studied by dilatometry. Furthermore, hardness and Charpy un-notched and V-notched impact toughness testing was performed and results were correlated to observed microstructures. With higher austenitisation temperature, the martensite and bainite start temperatures were lowered resulting in microstructures containing a higher volume fraction of retained austenite. Retained austenite transformed into martensite on cooling from the tempering temperature. Specimens that were austenitised at 1050°C or 1075°C and tempered twice contained fresh martensite. Applying a third tempering was therefore required to guarantee a fully tempered microstructure. The second tempering resulted in an increase of the un-notched impact energy while the third tempering did not have a pronounced effect. A triple tempering procedure could be preferable when austenitising at high temperatures to avoid undesirable fresh martensite in the tool microstructure.

TEKNIK OCH TEKNOLOGIER Materialteknik Bearbetnings-, yt- och fogningsteknik hsv//swe
ENGINEERING AND TECHNOLOGY Materials Engineering Manufacturing, Surface and Joining Technology hsv//eng
Cold work tool steel
microstructure
martensite
retained austenite
toughness
X-ray diffraction
scanning electron microscopy
dilatometry
Production Technology
Produktionsteknik
Manufacturing and materials engineering
Produktions- och materialteknik

Medvedeva, AnnaUddeholms AB, SE-683 85, Hagfors, Sweden. (author)
Svensson, Lars-Erik,1951-Högskolan Väst,Avdelningen för svetsteknologi (SV),PTW(Swepub:hv)larsve (author)
Karlsson, Leif,1952-Högskolan Väst,Avdelningen för svetsteknologi (SV),PTW(Swepub:hv)leikar (author)
Högskolan VästForskningsmiljön produktionsteknik(PTW) (creator_code:org_t)

In:10th TOOL Conference, Tool, conference proceedings: 10th TOOL Conference, s. 1-10

By the author/editor: Rehan, Arbab; Medvedeva, Anna; Svensson, Lars-E ...; Karlsson, Leif, ...

About the subject

ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Materials Engine ...; and Manufacturing Su ...

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