The tensile properties and their strain rate sensitivity have been investigated over the temperature range -76° to 150°C with strain rates ranging from 7.5×10^-6 to 15.2×10^-4sec^-1. The tensile properties at room temperature have also been investigated with strain rates ranging from 7.5×10^-6 to 45.6×10^-3sec^-1.
Embrittlement caused by decreasing strain rate is found in the maraging steels containing fine and coherent precipitates, and is also found in the overaged 13Ni-15Co-10Mo-0.2Ti maraging steel. The embrittlement appears most evidently at or just below room temperature. The ductilities of the maraging steels containing fine and coherent precipitates are increased by increasing strain rate at room temperature. Accordingly, the embrittleness at lower strain rates is attributable to the hydrogen embrittlement observed in steels.

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Experiments were carried out using the zone melting technique on the silicon-oxygen equilibrium in δ-iron at the solid-liquid equilibrium temperature.
The deoxidation constant with silicon in liquid iron was log K_Si(l)=-5.18([%Si(l)]<0.64) at this temperature, which is in good agreement with the values given in the literature.
The silicon-oxygen equilibrium relationship in o-iron at the solid-liquid equilibrium temperature is represented by the following equations: log{a_Si(s)•a_O(s)²/aSiO₂}=-7.19([%Si(s)]≤0.5) logf^Si_Si(s)=0.086[%Si(s)] logf^O_Si(s)=-15.9[%O(s)] logf^Si_O(s)=-9.05[%Si(s)]+30[%Si(s)]² ([%Si(s)]≤0.1) logf^o_o(s)≅0.

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In order to determine the factors responsible for the improved properties of coke quenched by a USSR type dry quencher, quenching and reheating-cooling tests were made on the coke produced in a 1/4-ton test oven and commercial ovens.
The tests showed that heat preservation in a pre-chamber is not related with property improvement and that the following three factors are effective on property improvement.
(1)As to chemical effect, unlike on wet quenching, the water gas reaction does not occur on dry quenching. The surface properties of coke are improved.
(2) As to heat effect, dry quenching reduces the residual stress in coke lumps, resulting in improvement of internal properties of the coke.
(3) As to mechanical abrasion effect, the structure of a dry quencher is suitable to remove fragile parts from the coke.
Internal structure models of both dry quenched coke and wet quenched coke are illustrated in this paper.

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The equilibrium distribution coefficients for chromium and nickel in the unidirectionally solidified iron-chromium-nickel alloys containing 5 to 20wt%Cr and 5 to 30wt%Ni were evaluated on the basis of the microsegregation ratio for the alloying elements. The solidification paths calculated from the values of the coefficients were in good agreement with those obtained experimentally.
The primary arm spacing in the alloys was proportional to the square root of the inverse cooling rate. The alloys whose primary crystal is δ had slightly larger primary arm spacing than those forming γ as the primary phase. The secondary arm spacing measured for some alloys was inverse as the 0.4 to 0.5 power of cooling rate and was independent of the alloy composition.

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By rapid quenching technique, metastable austenitic alloys with high strength and hardness have been found in Fe-Cr-C ternary system. This formation range is limited to about 1.0-2.2wt%C and 7-30wt%Cr. The austenite phase has ultra-fine grains of about 0.2μm in diameter. Their Vickers hardness, 0.2% proof stress and tensile fracture strength increase with the amounts of carbon and chromium, and the maximum values reach about 630DPN, 1500 and 1550MPa, respectively. These alloys are so ductile that no crack is observed even after closely contacted bending test. In addition, the changes in microstructure and mechanical properties of the tempered austenitic alloys have been investigated and it has been observed that a large secondary hardening occurs at about 870K due to phase transformation from austenite to equilibrium structure of ferrite and M₇C₃ pearlite. Thus the present alloys may be attractive as a fine gauge high-strength wire or plate.

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By the rapid quenching technique, metastable alloys with an austenite single phase and a duplex structure of austenite and cementite have been found in Fe-Ni-C ternary system. Their formation ranges are limited to about 1.2-2.0wt%C and 5-30wt%Ni for the austenite single phase and to about 2.0-3.2wt%C and 10-40wt%Ni for the duplex phases. These austenitic alloys have ultra fine grains of about 0.4μm in diameter and exhibit high hardness and strength as well as good elongation. The Vickers hardness, 0.2% proof stress and tensile fracture strength increase with the amounts of carbon and nickel, and the highest values attained are about 590DPN, 1300MPa and 1750MPa, respectively. The elongation increases with decrease in carbon or nickel content and is about 7% for Fe-20wt%Ni-1.8wt%C alloy. These high hardness and strength are due to the grain size refinement, the solid solution hardening by carbon and/or the precipitation hardening of fine M₃C carbide. In addition, the changes in the microstructures and mechanical properties during tempering have been examined. It has been observed that there is no change in the austenite structure except for the precipitation of cementite from the austenite phase and the strength and elongation decrease with increasing tempering temperature because of the grain coarsening of the austenite and cementite phases and the reduction in solid solubility of carbon in austenite.

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