| Autor: |
Wiengmoon, Amporn, Tareelap, Napachat, Imurai, Suttawan, Chairuangsri, Torranin, Pearce, John T.H. |
| Zdroj: |
Diffusion and Defect Data Part B: Solid State Phenomena; September 2018, Vol. 283 Issue: 1 p95-100, 6p |
| Abstrakt: |
The effects of destabilisation and tempering heat treatments on hardness and corrosion behavior in 28 wt.%Cr-2.6 wt.%C cast irons with up to 6 wt.%Mo addition were studied. The irons were destabilised at 1025 °C for 4 h and air cooled. Tempering was carried out at 450 °C for 4 h. Phase identification and microstructure were investigated by X-ray diffraction (XRD), light microscope (LM), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Vickers macro-hardness was measured. A potentiodynamic technique was used to indicate aqueous corrosion resistance. The results revealed that the as-cast microstructure of 28 wt.%Cr iron consisted of primary austenite dendrites with eutectic M7C3 carbides. In the irons with 6 wt.%Mo addition, eutectic carbides including M7C3, M23C6 and M6C were found. After destabilisation, the microstructure contained secondary carbide precipitates within an essentially martensitic matrix. Vickers macro-hardness of the as-cast and destabilised irons increased from 500 HV30 and 736 HV30 in the 28 wt.%Cr iron up to 570 HV30 and 870 HV30 in the iron with 6 wt.%Mo addition. Tempering slightly increased the macro-hardness. The as-cast 28 wt.%Cr iron had the lowest values for critical current density and passive current density. The destabilised + tempered treatment gave the lowest corrosion resistance. |
| Databáze: |
Supplemental Index |
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