Research On Structure And Wear-resistant Property Of Austempered Ductile Iron

Austempered Ductile Iron is one of the most important achievement among metallurgy of ductile cast iron in the nearly last fifty years. As its favorable integrate property of static state, especially the excellent plastic property and toughness with high strength,the stable mechanical property of static state,favorable abrasion resistance,high fatigue strength and so on, it has very far-ranging industrial application in the vocations of the mechanical engineering,metallurgy,transportation and constructional material. There are more and more attentions to the ADI as wear-resistant material in the application.The high manganese steel is to be as wear-resistant material, which has a long history. It exhibits excellent wear-resistance and impact ductility in the high impact condition. However, this steel don't display so well under the low impact condition. In this paper, the wear resistance of ADI were compaired with the general high manganese steel under the low impact condition.This article further studies on the casting technique,the heat treatment technology and the structure property of ADI. The experiment have researched on the metallurgical and mechanical property of ADI,in which have different content of Cu element,different media of isothermal quenching,different temperature and time of salt-bath quenching. The experiment also studied on the numbers and shape of graphite nodule in ADI that influenced by carbon content. The test sample content of low-carbon must stay at 980℃×8h annealing treatment. the conclusion can be safely drawn that if the parameters of austempering technique will stay at(900±5)℃×60min+(330±5)℃×50min,ADI with comparatively good comprehensive mechanical performance will be made. Meanwhile, this article also researched the wear-resistant property and the mechanics of ADI. The experiment results as follows:1. Some content of Cu will be increase the elongation of ADI obviously, but not as long as wear-resistence.2. On the condition of low impact abrasive, the wear-resistant property of ADI is better than the high manganese steel. There exist trough,micro-cut and crack on the wear surface of ADI which indicate the main wear mechanics is wear cutting and chipper in the low impact abrasive.3. The graphite nodules in ADI is easier to be wear. They may cut off the continuous matrices of ADI when they have too much. That is not good for the wear-resistant property. There will be increase the wear-resistant property of ADI, when reduce the content of carbon and the numbers of the graphite nodules...