Wear-resistant Steel Corrosion And Wear Performance In The Wet Grinding And Cavitation Conditions And Mechanisms

The impact-corrosion properties and the corresponding mechanism of kinds of wear -resistance steels under wet-grinding and cavitation in different medium are studied by means of mass loss, SEM, micro-hardness , electrochemistry and surface roughness measurement et al.During the tests on wear-resistant properties in acid circumstance with impact particals of different sizes, it is found that the wear-resistant properties of carbon high alloy steel, high manganese steel and medium carbon alloy steel are controlled by the hardness of impacting grain when the ratio of sample hardness to impacting partical hardness is less than 0.85.Low carbon high alloy steel and high manganese steel are impacted in corrosive slurry with different impact stress. It is showed that the material mass loss of high manganese steel is accelerated by the corrosion circumstance due to its poor corrosive-resistant properties. On the other hand, low carbon high alloy steel showed excellent corrosive - erosion resistance to corrosion circumstance due to the excellent corrosion-resistant and cracking-blocking lathy martensite microstructure of high hardness blocking crack spreading.To comparatively study the mechanism of corrosive - erosion resistance of low carbon high alloy steel, different kinds of electrochemistry experiments were conducted, including Potentiodynamic polarization curves, Nyquist plots and Rp measured. It is showed that low carbon high alloy steel exhibit excellent corrosive-wear-resistance properties in acid and neuter circumstances, due to the existence of easy-sample-surface-form passivation elements, Ni, Cr, Mo and the quick -passivation-mending ability of Mo. However, in alkalescent circumstance, low carbon high alloy steel is in active dissolving conditions, resulting in lower corrosion-resistance properties than in acid and neuter circumstance. On the contrary, high manganese steel is in active dissolving states in both acid and neuter circumstances, resulting in the large corrosive current. In alkalescent slurry, due to the anode corrosion-blocking effect of cathode polarization, corrosion-resistant properties of high manganese steel are superior to in acid and in neuter circumstances.Cavitative resistances of low carbon high alloy steel and high manganese steel are also studied. To identify the influence of impact, corrosion and wear corrosive - erosion process and the interaction among these three factors, a systemic electrochemistry exoeriments in dynamic condition are conducted with cavitation experimental equipment. Research results show that the ratio of the corrosion caused erosion increment (7.8%) and that of erosion caused corrosion increment (7.2%) in gross are similar, indicating that corrosive medium has little influence on the cavitation-erosion-resistance properties of low carbon high alloy steel in acid and neutral circumstances. However, as to high manganese steel, the corresponding ratios changed to 29.3% and 11.2%, respectively, indicating that corrosion plays primary role on the resistance properties of high manganese steel to cavitation erosion. But in alkalescent circumstance, high manganese steel exhibit more excellent cavitation corrosion resistance property than that of low carbon high alloy steel. Under cavitative condition, crackles produce and break off easily in the ferrite phase of low carbon high alloy steel, finally resulting in the sample damage. On the contray, in early cavitation test, high manganese steel has very excellent cavitative resistance by dislocations slippage and work-harding ; while in late cavitation test, dislocations crash and damage the samples.