Premium
Calculation of liquidus temperature of low and high alloyed iron base melts from their chemical composition by means of the equivalence factors
Author(s) -
Schürmann Eberhard,
Djurdjevic Mile,
Nedeljkovic Ljubomir
Publication year - 1997
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199700548
Subject(s) - liquidus , equivalence point , melting point , carbon fibers , metallurgy , thermodynamics , chemistry , carbon steel , solidus , materials science , composite material , corrosion , physics , electrode , alloy , composite number , potentiometric titration
Liquidus temperature of a steel is calculated from its chemical composition according to the so far proposed procedures by simply summing up the iron melting point lowering effects of all in the steel contained elements X i , as they are given by approximating the iron liquidus curves with the straight lines in the corresponding binary Fe‐ X i systems. The intensification of the iron melting point lowering effect with the increasing concentration of each element contained in the steel has not been at all or only partly taken into account in this approach. This is the reason why the calculated steel liquidus temperatures are not accurate enough. In the here proposed new calculation procedure the iron melting point lowering effect of an alloying element X i is first translated into an equivalent effect of carbon in the Fe‐C system by converting the concentration of X i into an equivalent concentration of carbon taken as a reference element. The carbon equivalent iron melting point lowering effect of all elements contained in the steel including carbon is then evaluated by summing up the calculated equivalent carbon concentrations of all elements together with carbon into a fictitious total equivalent carbon concentration. A so calculated total equivalent carbon concentration has made it possible to determine with a good accuracy the steel liquidus temperature along the stable δ/α or γ liquidus lines in the Fe‐C system. The success of a melting point calculation is strongly dependent on the accuracy of the equivalence factor equations for each alloying element. They are derived by relating the iron liquidus line in the binary Fe‐ X i system to that in the Fe‐C phase diagram.