Study on improvement of hard phase morphology and properties of hypoeutectic Fe–C–B alloy

• We find a new effective way to improve the toughness of non-chromium Fe-C-B alloy.
• The hard phase morphology of the alloy can be improved significant.
• Effect of austenitizing temperature is investigated and analyzed.
• The wear resistance of the treated alloy is close to that of heat treated Cr20Mo.
• The toughness of the treated alloy is better than that of heat treated Cr20Mo.

Attempt to improve the hard phase morphology and properties of non-chromium hypoeutectic Fe–C–B alloy containing 0.36 wt.% C and 1.48 wt.% B by the thermomechanical treatment, which is a integrated process of hot deformation and quenching, is reported in the paper. The experiment results show that hot deformation can crush the continuous hard phase network in the alloy into gathered particles, and quenching under different austenitizing temperature make the hard phase particles in the deformed samples tend to merge and present stripe and bulk dispersed distribution in the matrix. Analysis results indicate that with the increase of austenitizing temperature, the volume of hard phase in the alloy reduced while the morphology of it tends to form continuous network shape again. Such change of hard phase morphology has significant effect on the properties especial impact value and wear resistance of the alloy. When the alloy was deformed and quenched at 1050 °C, it reaches 58HRC of hardness and 9.3 J of impact value, which is much higher than that of untreated alloy, and the wear resistance of it is very close to heat-treated Cr20Mo high chromium cast iron while the impact value is much better.