TY - GEN

T1 - Transfer of ausforming parameters to scaled forging tools

AU - Behrens, Bernd Arno

AU - Brunotte, Kai

AU - Petersen, Tom

AU - Relge, Roman

AU - Till, Michael

N1 - Funding Information: The authors would like to thank the German Research Foundation (DFG) for the financial support of the project (Project-Nr. 318628894)

PY - 2021/9/15

Y1 - 2021/9/15

N2 - Forging tools are exposed to cyclically changing thermo-mechanical stress conditions leading to its failure. Damage phenomena on the tool engraving cannot be entirely avoided by hardening the surface, as this leads to a more brittle behaviour and thus to lower ductility of the material, which can intensify the occurring damage effects. The forming of steel below the recrystallisation temperature in the metastable austenite area, known as ausforming, offers the possibility to increase strength and hardness without affecting ductile properties, due to simultaneous grain refinement. In this study, ausforming was used to produce forging dies with increased wear resistance from tool steel X37CrMoV5-1 (AISI H11) by achieving higher hardness in the surface area while maintaining a ductile base material. Suitable forming and tempering parameters were derived from previous studies in which ausformed cups from tool steel X37CrMoV5-1 (AISI H11) with a downscaled geometry have been investigated in mechanical pulsation tests. To achieve comparable properties, a process route with adapted surface-cooling conditions, a global true plastic strain of φ = 0.25 and a tempering temperature of 300 °C were applied. Further, the ausformed dies were compared with conventionally forged dies. The metallographic analysis and hardness measurements show that an increased hardness in the surface area can also be obtained for the actual formed dies. In order to see the influence of the thermomechanical alternating load on the die engraving under forging conditions, the performance of the ausformed tool will be investigated in service-life-time tests and compared to warm-formed and machined reference tools.

AB - Forging tools are exposed to cyclically changing thermo-mechanical stress conditions leading to its failure. Damage phenomena on the tool engraving cannot be entirely avoided by hardening the surface, as this leads to a more brittle behaviour and thus to lower ductility of the material, which can intensify the occurring damage effects. The forming of steel below the recrystallisation temperature in the metastable austenite area, known as ausforming, offers the possibility to increase strength and hardness without affecting ductile properties, due to simultaneous grain refinement. In this study, ausforming was used to produce forging dies with increased wear resistance from tool steel X37CrMoV5-1 (AISI H11) by achieving higher hardness in the surface area while maintaining a ductile base material. Suitable forming and tempering parameters were derived from previous studies in which ausformed cups from tool steel X37CrMoV5-1 (AISI H11) with a downscaled geometry have been investigated in mechanical pulsation tests. To achieve comparable properties, a process route with adapted surface-cooling conditions, a global true plastic strain of φ = 0.25 and a tempering temperature of 300 °C were applied. Further, the ausformed dies were compared with conventionally forged dies. The metallographic analysis and hardness measurements show that an increased hardness in the surface area can also be obtained for the actual formed dies. In order to see the influence of the thermomechanical alternating load on the die engraving under forging conditions, the performance of the ausformed tool will be investigated in service-life-time tests and compared to warm-formed and machined reference tools.

KW - Ausforming

KW - Forging die inserts

KW - Metastable austenite

KW - Wear resistance

UR - http://www.scopus.com/inward/record.url?scp=85124342528&partnerID=8YFLogxK

U2 - 10.37904/metal.2021.4118

DO - 10.37904/metal.2021.4118

M3 - Conference contribution

AN - SCOPUS:85124342528

SP - 247

EP - 252

BT - METAL 2021 - 30th Anniversary International Conference on Metallurgy and Materials, Conference Proceedings

T2 - 30th International Conference on Metallurgy and Materials, METAL 2021

Y2 - 26 May 2021 through 28 May 2021

ER -