化学成分对铁-铬-碳系堆焊材料抗磨蚀性能的影响

为解决水轮机在含沙水中的快速破坏,对铁-铬-碳系堆焊材料进行了研究,并在自行设计、制造的沙水旋流磨蚀试验机上进行了评定堆焊材料的抗磨蚀性能试验。试验结果表明,材料的抗磨蚀性能主要决定于初生析出相碳化铬的含量。随着碳、铬含量的降低,初生析出相由硬度高于共晶的碳化铬变为硬度低于共晶的合金固溶体,从而降低了堆焊层的硬度与抗磨蚀性能。含碳量进一步降低,堆焊层组织中的共晶将减少,固溶体相将相应增加,这样堆焊层的硬度与抗磨蚀性就会进一步降低。硼能提高高碳高铬白口铁焊条堆焊层的抗磨蚀性。硼对13%铬钢焊条堆焊层的抗磨蚀性的影响比对高碳高铬白口铁焊条更加明显。随着含硼量的增加,13%铬钢焊条堆焊层的硬度与抗磨蚀性基本成直线增长。

EFFECT OF CHEMICAL COMPOSITION ON THE EROSION-CAVITATION RESISTANCE OF SURFACING MATERIALS OF Fe-Cr-C SYSTEM FOR HYDROTURBINE

In order to find an erosion-cavitation resistant material for hydroturbine,surfacing materials of Fe-Cr-C system were studied and evaluated in the laboratory with rota-ting blades type erosion-cavitation test apparatus which was designed and made by our-selves.Test results show that the ability of surfacing material to resist erosion-cavita-tion is essentially dependent on the quantity of primary chromium carbide in the microconstituents.Decreasing the carbon and chrome content in surfacing material would change the primary phase from chromium carbide,which is harder than eutectic,to alloyed austenite,which is softer than eutectic.Therefore,it would also lower the har-dness and the erosion-cavitation resistance of surfacing material.Further decreasing the carbon content would further lower the hardness and the erosion-cavitation resistance due to the decrease of eutectic and increase of austenite.The effect of B on the erosion-cavitation resistance of surfacing layer of 1.15%C,12%Cr steel electrode is more pronounced than on that of high carbon,high chrome white iron electrode.To increase the boron content in 0.1%C,13%Cr steel electrode would almost linearly increase the hardness and the erosion-cavitation resistance of surfacing material.