Research and Development of High Temperature Wear Resistant Materials with High Carbides

本研究旨在通过熔炼工艺和两种合金的结合，研制出高碳化物含量的耐高温韦姆材料。剪切应变在600 ℃开始增加，在800 ~ 1000 ℃范围内显著增大。高温强度，即剪切应力在600 ℃以下基本不变，与室温强度基本相同。在600 ℃以上，强度随温度的升高而逐渐降低，但即使在800 ℃，强度也在150 MPa左右。在10%Cr共晶铸铁中分别添加10%的强碳化物形成元素V、Mo、Nb、W，在1100 ℃、P_（O_2）= 1的条件下进行了氧化试验。V大大增加了铁的氧化，换句话说，它恶化了抗氧化性。为了提高含大量碳化物的高铬铸铁的脆性，采用纯铬钎料钎焊26%Cr共晶铸铁与低碳钢，将具有很高抗氧化性和优良上级高温性能的26%Cr共晶铸铁与低碳钢进行了钎焊连接。铜填料当两种合金在1100 ~ 1180 ℃保温一定时间后，在铜液中析出的合金相（Fe-Cr-Cu-C）使它们之间形成良好的连接，接头的结合强度与母材相当。该复合材料有望用于高温耐磨零件。

The purpose of this research project is to develop the high temperature wem resistant materials with higher amount of carbides by means of melting process and by joining the two kinds of alloys.Properties of the eutectic high Cr cast irons containing 10% to 40%Cr were investigated at the temperatures up to 1000 ﾟC using a torsion testing machine. Shear strain started to increase at 600 ﾟC and enlarged markedly in the temperature range from 800ﾟC to 1000ﾟC. High temperature strength, that is, shear stress disn't vary up to 600 ﾟC and it kept about the same strength as that at room temperature. Over 600 ﾟC, the strength decreased gradually as the temperature was increased, but even at 800ﾟC the strength was about 15OMPa. The 27%Cr cast iron was found to have most excellent strength at high temperatures.Oxidation test at 1100 ﾟC was carried out under Po_2= 1 ate using 10%Cr eutectic cast iron separately added 10% of strong carbide forming element such as V, Mo, Nb and W. V greatly increased the oxidation of the iron, and in other words it worsened the oxidation resistance. On the other hand, each element except V decreased the oxidation ratio and Nb improved oxidation resistance remarkably.In order to reinforce the brittleness of high Cr cast iron with large amount of embides, 26%Cr eutectic iron, which has very high oxidation resistance and very superior high temperature properties, and mild steel were joined by means of brazing with pure. copper filler. When both alloys were held at the temperature range of 1100ﾟC to 1180ﾟC for enough time, they were well connected each other by alloyed phase(Fe-Cr-Cu-C)precipitated in molten copper and bond strength of the joint showed aliaest the same value as mother materials. This composite could be expected to use for wear resistant parts at high temperature.