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Title: Theoretical and experimental study of the rule for heat transfer coefficient in hot stamping of high strength steels

Heat transfer is a crucial aspect for hot stamping process, the fully austenitized boron steel blank with temperature about 900°C is transferred to the tool, then formed rapidly and quenched in the cooled tool. The desired fully martensitic transformation will happen only if the cooling rate exceeds a critical value approximately 27 K/s. During such process, the heat transfer coefficient (abbreviated as HTC) between the tool and blank plays a decisive role for the variation of the blank temperature. In this work, a theoretical formula based on the joint-roughness model is presented to describe the law of HTC, which relies on the roughness, hardness, and other material parameters of the tool and blank. Moreover, a non-contact temperature measuring system based on the infrared thermal camera is built to catch the temperature change course, and then the HTC value is derived through the inverse analysis. Based on the theoretical and experimental results, the change rule of HTC especially its dependence on the process pressure will be discussed in detail.
Authors:
; ; ;  [1]
  1. Institute of Forming Technology and Equipment, Shanghai Jiao Tong University, 1954 Hua Shan Road, Shanghai, 200030 (China)
Publication Date:
OSTI Identifier:
22261675
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1567; Journal Issue: 1; Conference: NUMISHEET 2014: 9. international conference and workshop on numerical simulation of 3D sheet metal forming processes, Melbourne (Australia), 6-10 Jan 2014; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 97 MATHEMATICAL METHODS AND COMPUTING; APPROXIMATIONS; BORON; COOLING; HARDNESS; HEAT TRANSFER; MEASURING METHODS; PHASE TRANSFORMATIONS; STEELS; VARIATIONS