Abstract
The formation of carbide-dispersed layer (CD layer) by carburizing various vanadium steels at temperatures between 923 and 1273 K was studied, and the wear characteristics of these vanadium steels were examined.
Results obtained are as follows:
(1) A CD layer formed by carburizing below A1 point contains fine platelet V4C3 carbides in ferrite matrix. The crystal orientation relationships between ferrite and V4C3 carbide are (100)V4C3\varparallel(100)α-Fe, [010]V4C3\varparallel[011]α-Fe and [001]V4C3\varparallel[0\bar11]α-Fe, known as Baker-Nutting relationship.
(2) A CD layer grew in proportion to the square root of time, and the growth rate below A1 point was explained by a kinetic equation proposed by Wagner for the internal oxidation. The permeability for carbon in Fe-V alloys is expressed as follows;
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(3) Vanadium steels carburized and quench-tempered shows good wear resistance at both low and high sliding speeds, and a steel containing 2.3%V shows better wear resistance than SKD 11 steel. It is concluded from these results that fine-dispersed carbides are very effective in improving wear resistance.
