Thermophysical Properties of Five Industrial Steels in the Solid and Liquid Phase

B Wilthan,W Schützenhöfer,G Pottlacher

doi:10.1007/s10765-017-2220-z

Abstract

The need for characterization of thermophysical properties of steel was addressed in the FFG-Bridge Project 810999 in cooperation with our partner from industry, Böhler Edelstahl GmbH & Co KG. To optimize numerical simulations of production processes such as plastic deformation or remelting, additional and more accurate thermophysical property data were necessary for the group of steels under investigation. With the fast ohmic pulse heating circuit system and a commercial high-temperature Differential Scanning Calorimeter at Graz University of Technology, we were able to measure the temperature-dependent specific electrical resistivity and specific enthalpy for a set of five high alloyed steels: E105, M314, M315, P800, and V320 from room temperature up into the liquid phase. The mechanical properties of those steels make sample preparation an additional challenge. The described experimental approach typically uses electrically conducting wire-shaped specimen with a melting point high enough for the implemented pyrometric temperature measurement. The samples investigated here are too brittle to be drawn as wires and could only be cut into rectangular specimen by Electrical Discharge Machining. Even for those samples all electrical signals and the temperature signal can be recorded with proper alignment of the pyrometer. For each material under investigation, a set of data including chemical composition, solidus and liquidus temperature, enthalpy, electrical resistivity, and thermal diffusivity as a function of temperature will be reported.

Highlights

For about 70 % of all industrially formed metal parts, the production starts with the liquid metal/alloy [1]
The chemical compositions are listed in Table 1, and some typical applications of the different steels are summarized in Table 2 and described in more detail in the data sheets [2,3,4,5,6]
The subsections list the results from the pulse heating and Differential Scanning Calorimeter (DSC) measurements in the form of polynomial fits

Summary

Introduction

For about 70 % of all industrially formed metal parts, the production starts with the liquid metal/alloy [1]. A key limitation to the successful introduction of these models is the lack of thermophysical data required as input parameters for simulation tools. Experimentally obtained thermophysical property data of pure metals and of binary and multi-alloy systems are of great importance. More accurate property data will lead to a better scientific understanding of liquid metals and alloys and improve the results of numerical simulation tools for optimizing metallurgical processes. For this study a set of five high alloyed steels, optimized for different applications, was chosen: E105—used in aviation, M314 and M315—steels for plastic molds, P800—a steel for automotive parts with soft magnetic behavior, and V320— representing heat treatable steels. The chemical compositions (chemical analysis performed by Böhler Edelstahl GmbH & Co KG) are listed in Table 1, and some typical applications of the different steels are summarized in Table 2 and described in more detail in the data sheets [2,3,4,5,6]

Methods

Results

Conclusion