Field Processing Performance Of Hard Alloy And The Influence Of The Organization

Hard alloy as an extremely important functional materials, can be widely used in measuring tools, moulds and wear parts and high temperature resistant and corrosion resistant parts. Since the1950s people have done lots of research including heat treatment on it to improve the alloy performance, enhance product performance. Predecessors carred out related research on nano hard alloy, gradient hard alloy, coating technology, field processing technology, but field processing technology on hard alloy needs deep study. Therefore, this thesis, the cobalt-based hard alloy (YG6(WC-6%Co), YG15(WC-15%Co) as example), nickel-based hard alloy (YN6(WC-6%Ni), YN15(WC-15%Ni) as example) made in sichuan ke-li-tie Co.LTD, were investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy (OM), transverse rupture strength, vickers hardness and force values to do research on after field treatments (conventional heat treatment, cryogenic processing, ultrasonic quenching process, the magnetic treatment, electric field tempering etc). The theory reasons of changes induced by the treatments were discussed. The main research results are as follows:(1)Heat treatment process (quenching temperature, quenching mode) have different effects on organization and performance of two kinds of hard alloy. With the increase of quenching temperature, the transverse rupture strength of cobalt-based hard alloy (YG15, for example) increase in the first then decrease, the best quenching temperature is1000℃; In this thesis’s experiment conditions the transverse rupture strength of ni-based hard alloy (YN15, for example) after quenching are better than sintering state, but with the increase of quenching temperature, the trend slow down. If quenching cooling way is faster, aggrandizement effect of transverse rupture strength and vickers hardness of cobalt-based hard alloy (YG6and YG15, for example) will be more obvious.Vickers hardness of ni-based hard alloy (YN6, for example) after quenching declined slightly, and cooling way faster, the greater the reduction; And quenching way faster, the transverse rupture strength is rising, but small scale.(2) The research scope of conditions are:(1100±5)℃,20-25min insulation, magnetic quenching15min with2T intensity, then3h annealing with temperature (500±5)℃; conventional quenching treatment with YG6(WC-6%Co) was also conducted. Results show that:After magnetic quenching, Vickers hardness of YG6increases by3%, transverse rupture strength increases by18%,impact toughness increases by24%, coervice force increases by25%; quenching without magnetic, Vickers hardness of YG6increases by2.38%, transverse rupture strength increases by11.34%,impact toughness increases by14.05%, no significant change in coervice force. While transverse rupture strength of YN6increases by5.9%, impact toughness increases by6.9%,there was no significant change in vickers hardness and coervice force of YN6.(3) Transverse rupture strength of cobalt-based hard alloy (YG6, for example) and ni-based hard alloy (YN6, for example) drop significantly, vickers hardness also declines slightly after Ultrasonic quenching.(4) Vickers hardness and transverse rupture strength of cobalt-based hard alloy (YG6and YG15, for example) has improved, especially transverse rupture strength increased iobviously after Liquid nitrogen cryogenic quenching.After two times liquid nitrogen cryogenic quenching transverse rupture intensity of YG15increase by23.1%.(5) Compared to250℃electrostatic field tempering and ordinary tempering in the same state the physical properties of YG15alloy doesn’t produce obvious difference.