Study of defects in directed energy deposited Vanadis 4 Extra tool steel
Artikel i vetenskaplig tidskrift, 2022

A cold work tool steel with varied number of layers was deposited on a substrate of hot work tool steel for hard-facing by directed energy deposition technique. This study deals with the defects and microstructure in the as-cladded tool steels. Defects, including pores and cracks, were found in the deposited zone, the number of which increased with the building height or number of layers deposited. Large irregular pores were mainly located at the lower regions of the deposited layers. The formation of this type of pores was attributed to the segregation of alloy elements on the pore surface and insufficient heat input. Non-equilibrium eutectic microstructure was a characteristic feature in the regions adjacent to the pores. Cracking, on the other hand, tended to occur in the upper part of the deposited layers. Two important contributing factors were identified for cracking. The first one was the microstructural gradient, which was modified from fine cellular dendrite to columnar dendrite when moving from the bottom to the top deposited layer. Second, the deposited cold work tool steel exhibited a relatively large temperature range of solidification, as simulated by Thermocalc software, leading to high sensitivity to hot cracking.

Directed energy deposition

Hot cracking

Tool steel


Pore formation


Miwen Yuan

Chalmers, Industri- och materialvetenskap, Material och tillverkning

Central South University

Seshendra Karamchedu


Yicheng Fan

ASSAB Tooling Technology Ltd.

Libin Liu

Central South University

Lars Nyborg

Chalmers, Industri- och materialvetenskap, Material och tillverkning

Yu Cao

Chalmers, Industri- och materialvetenskap, Material och tillverkning

Journal of Manufacturing Processes

1526-6125 (ISSN)

Vol. 76 419-427


Bearbetnings-, yt- och fogningsteknik

Annan materialteknik

Metallurgi och metalliska material


Chalmers materialanalyslaboratorium



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