Vol.45, No.2, 101 ~ 109, 2007
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Title |
Effect of Co Addition on Tensile Properties in Secondary Hardening Co-Ni Alloy Steels |
권훈 Hoon Kwon , 이건배 Kon Bae Lee , 심호섭 Ho Seop Sim , 조기섭 Ki Sub Cho , 양형렬 Hyung Ryul Yang |
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Abstract |
The effect of Co additions on tensile properties in the secondary hardening Co-Ni alloy steels has been studied in as-quenched and aged conditions. Three kinds of (5-13)Co-11Ni steels, containing Mo and Cr, were severely multipass-rolled in unrecrystallized region and followed by accelerated cooling. In as-quenched condition, an increase in yield strength and a decrease in uniform elongation with an increase in Co content are closely related with a decrease in the amount of retained austenite. In peak-aged condition, yield and tensile strengths and peak hardness increased with the increase of Co content, but peak time remained around 5 hours. Thus, Co additions would enhance the nucleation of fine M2C carbides rather than their growth. |
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Key Words |
ultrahigh strength steel, Co-Ni steel, secondary hardening, tensile properties, severe deformation |
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