AN INVESTIGATION ON THERMAL AND MECHANICAL STABILITY OF MOLD MATERIALS FOR STEEL CASTINGS.
Interim rept. for 28 Jun 63-27 Jun 64,
CASE INST OF TECH CLEVELAND OHIO DEPT OF METALLURGY
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Test apparatus and technique were developed to measure the tensile strength of molding materials at elevated temperatures. The measurements of tensile strength obtained from this equipment permits a qualitative evaluation of the mechanical stability of the mold as molten steel enters and solidifies in the mold. The mold stability obtained with various refractory aggregate-binder combinations is a significant factor in controlling dimensional tolerances in the steel casting. Several rammed mold materials consisting of various combinations of refractory aggregates and binders were investigated for use in producing high quality steel castings. Close dimensional control of the castings was obtained with fused silica, calcined alumina and silica sand bonded with sodium silicate and green, western bentonite bonded mullite. Better casting surfaces were obtained with the fused silica aggregate. A modified sodium silicate binder utilizing silicon metal fines to promote setting was investigated. This sodium silicatesilicon fines binder combined with either fused silica or silica sand refractories provided a mold for casting steel to close dimensions with a good cast surface. Author