The effect of aluminum on the work hardening and wear resistance of hadfield manganese steel
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I.
INTRODUCTION
H A D F I E L D manganese steel is used widely by the mining, earthmoving, and railroad industries because of its rapid work-hardening rate and high gouging wear resistance. The ASTM standard covering this steel allows composition ranges from 1.0 to 1.4 pet C and from 10 to 14 pet Mn. ~The gouging wear resistance of Hadfield steel increases with increasing carbon in solution in austenite 2 up to a practical limit of 1.2 pct C imposed by carbide precipitation in heavy casting sections. Several studies 3'4 indicated that resistance to gouging wear is directly related to rapid work hardening in this alloy. Previous researchers attributed the rapid work-hardening rate in Hadfield steel to strain-induced transformation of 3/ to c~ or e martensite, 5 fine mechanical twinning, 6 stacking fault-dislocation interactions, 7 and carbon atom-dislocation interactions. 8'9'~~Recently, Dastur and Leslie4 showed that the principal mechanism of rapid work hardening is dynamic strain aging caused by the reorientation of carbonmanganese couples in the strain fields of dislocations. They suggested that wear resistance might be improved by adding a solid-solution element which increased the solubility of carbon in austenite and simultaneously increasing carbon content. To increase effectively the solubility of carbon in austenite in Hadfield steel, a solid solution element must decrease the activity of carbon in austenite but not interact with carbon so strongly as to form carbides, must not interact with iron and manganese to form intermetallic compounds, must not decrease seriously the castability of the alloy, and must be economical. A survey of the effects of alloying elements on the activity of carbon in austenite" indicates that only alumiB. K. ZUIDEMA, formerly Graduate Student in the Department of Materials and Metallurgical Engineering, University of Michigan. Ann Arbor, MI, is Development Supervisor, Solidification Research. Howmet Turbine Components Corporation, Techmcal Center, Whitehall, MI 49461. D. K. SUBRAMANYAM is Metallurgist, ABEX Corporahon Research Center, Mahwah, NJ 07430. W C. LESLIE, formerly Professor, is Professor Emeritus, Department of Materials and Metallurgical Engineering, University of Michigan, Ann Arbor, MI 48109. Manuscript submmed December 2, 1985. METALLURGICALTRANSACTIONS A
num meets all these requirements. The purposes of this study were to determine the effect of aluminum on carbon solubility and work-hardening rate in Hadfield steel and to determine if wear resistance could be improved by simultaneous aluminum additions and increased carbon content.
II.
EXPERIMENTAL PROCEDURE
Sixteen alloys of nominal composition 13.5 pct Mn, 0.75 pet Si, and varying in carbon from 1.00 to 1.75 pet and in aluminum from 0.0 to 4.0 pct were prepared by air induction melting. Each alloy was cast into one 19 kg Y-block mold to provide one 7.6 cm • 6.4 cm • 16.5 cmblockfor multiple test purposes and one 23 kg octabar mold to provide eight 16.5 cm tension test specimen blanks. Chemical compositio
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