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Title: Solidification and solid-state transformation mechanisms in Si alloyed high-chromium white cast irons

Abstract

Chromium white cast irons are widely used in environments where severe abrasion resistance is a dominant requirement. To improve the wear resistance of these commercially important irons, the US Bureau of Mines and CSIRO Australia are studying their solidification and solid-state transformation kinetics. A ternary Fe-Cr-C iron with 17.8 wt pct (pct) Cr and 3.0 pct C was compared with commercially available irons of similar Cr and C contents with Si contents between 1.6 and 2.2 pct. The irons were solidified and cooled at rates of 0.03 and 0.17 K/s to 873 K. Differential thermal analysis (DTA) showed that Si depresses the eutectic reaction temperature and suggests that it has no effect upon the volume of eutectic carbides formed during solidification. Microprobe analysis revealed that austenite dendrites within the Si alloyed irons cooled at 0.03 and 0.17 K/s had C and Cr contents that were lower than those of dendrites within the ternary alloy cooled at the same cooling rate and a Si alloyed iron that was water quenched from the eutectic temperature. These lower values were shown by image analysis to be the result of both solid-state growth (coarsening) of the eutectic carbides and some secondary carbide formation. Hardnessmore » measurements in the as-cast condition and after soaking in liquid nitrogen suggest an increase in the martensite start temperature as the Si content was increased. It is concluded that Si's effect on increasing the size and volume fraction of eutectic carbides and increasing the matrix hardness should lead to improved wear resistance over regular high-chromium white cast irons.« less

Authors:
 [1];  [2]
  1. Bureau of Mines, Albany, OR (United States)
  2. Commonwealth Scientific Research Organization, Woodville (Australia)
Publication Date:
OSTI Identifier:
6519655
Resource Type:
Journal Article
Journal Name:
Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)
Additional Journal Information:
Journal Volume: 24A:4; Journal ID: ISSN 0360-2133
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CAST IRON; SOLIDIFICATION; WEAR RESISTANCE; ABRASION; CARBIDES; CARBON; CHROMIUM ALLOYS; DIFFERENTIAL THERMAL ANALYSIS; ELECTRON MICROPROBE ANALYSIS; HARDNESS; PHASE TRANSFORMATIONS; SILICON ALLOYS; ALLOYS; CARBON COMPOUNDS; CHEMICAL ANALYSIS; ELEMENTS; IRON ALLOYS; IRON BASE ALLOYS; IRON CARBIDES; IRON COMPOUNDS; MECHANICAL PROPERTIES; MICROANALYSIS; NONDESTRUCTIVE ANALYSIS; NONMETALS; THERMAL ANALYSIS; TRANSITION ELEMENT COMPOUNDS; 360102* - Metals & Alloys- Structure & Phase Studies

Citation Formats

Laird, G II, and Powell, G L.F. Solidification and solid-state transformation mechanisms in Si alloyed high-chromium white cast irons. United States: N. p., 1993. Web. doi:10.1007/BF02656520.
Laird, G II, & Powell, G L.F. Solidification and solid-state transformation mechanisms in Si alloyed high-chromium white cast irons. United States. https://doi.org/10.1007/BF02656520
Laird, G II, and Powell, G L.F. 1993. "Solidification and solid-state transformation mechanisms in Si alloyed high-chromium white cast irons". United States. https://doi.org/10.1007/BF02656520.
@article{osti_6519655,
title = {Solidification and solid-state transformation mechanisms in Si alloyed high-chromium white cast irons},
author = {Laird, G II and Powell, G L.F.},
abstractNote = {Chromium white cast irons are widely used in environments where severe abrasion resistance is a dominant requirement. To improve the wear resistance of these commercially important irons, the US Bureau of Mines and CSIRO Australia are studying their solidification and solid-state transformation kinetics. A ternary Fe-Cr-C iron with 17.8 wt pct (pct) Cr and 3.0 pct C was compared with commercially available irons of similar Cr and C contents with Si contents between 1.6 and 2.2 pct. The irons were solidified and cooled at rates of 0.03 and 0.17 K/s to 873 K. Differential thermal analysis (DTA) showed that Si depresses the eutectic reaction temperature and suggests that it has no effect upon the volume of eutectic carbides formed during solidification. Microprobe analysis revealed that austenite dendrites within the Si alloyed irons cooled at 0.03 and 0.17 K/s had C and Cr contents that were lower than those of dendrites within the ternary alloy cooled at the same cooling rate and a Si alloyed iron that was water quenched from the eutectic temperature. These lower values were shown by image analysis to be the result of both solid-state growth (coarsening) of the eutectic carbides and some secondary carbide formation. Hardness measurements in the as-cast condition and after soaking in liquid nitrogen suggest an increase in the martensite start temperature as the Si content was increased. It is concluded that Si's effect on increasing the size and volume fraction of eutectic carbides and increasing the matrix hardness should lead to improved wear resistance over regular high-chromium white cast irons.},
doi = {10.1007/BF02656520},
url = {https://www.osti.gov/biblio/6519655}, journal = {Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)},
issn = {0360-2133},
number = ,
volume = 24A:4,
place = {United States},
year = {Thu Apr 01 00:00:00 EST 1993},
month = {Thu Apr 01 00:00:00 EST 1993}
}