Ultra-Fine Grain Steel Produced by Carbide Dispersion Carburizing Process

C-D渗碳——获得分散碳化物颗粒的渗碳处理——已经在几种钢上进行了试验，以生产超细晶粒钢。所得结果总结如下：1。钒具有较大的溶解度，是实现碳化物精细分散最有利的元素，而v -碳化物对铁基体的溶解度要小得多。Cr、Mo、W、Co能有效提高合金的二次硬化性和耐磨性。在这些初步试验的基础上，确定了钢的组成为7%V、2%Cr、4%Mo、3%W和5%Co.2。C-D钢的力学性能对上述钢的力学试验结果如下：(1)抗拉强度；1.8GPa,(2)维氏硬度；950- 1000,(3)耐磨性优于商用高速钢，(4)抗弯强度；3.4绩点。这些数值表明，C-D钢具有较好的强度和塑性，这主要是由于其超细晶粒组织。C-D钢有望用于薄型零件，即：、精细刀具、精细钻头、点印销钉等。从技术和经济两个方面对其适用性进行审查。

The C-D carburizing-- carburizing treatment for obtaining dispersed carbide particles -- has been tried on several kinds of steel to produce ultra-fine grain steels. The results obtained are summarized as follows :1. Function of Alloying Elements in C-D Steel Vanadium is the most profitable element to realize the fine dispersion of carbides, because it has a large solubility, while the V-carbide has a much less solubility to the Fe-matrix. Cr, Mo, W and Co are effective to improve the secondary hardening and abrasive resistance. On the basis of these preliminary experiments, the composition of steel was chosen as 7%V, 2%Cr, 4%Mo, 3%W and 5%Co.2. Mechanical Properties of C-D Steel The results of mechanical tests on the above-mentioned steel are as follows; (1) tensile strength; 1.8GPa, (2) Vickers hardness;950- 1000, (3) abrasion resistance is better then the commercial high speed steel, and (4) bending strength; 3.4 GPa. These values indicate that the,C-D steel is superior in both the strength and ductility, which is mainly due to the ultra-fine grain structure.3. Practical Use The C-D steel is expected to be useful to thin parts,i.e.,fine cutters, fine drills, pins for dot-printing and so on. The examination of applicability will be carried on from the both sides of technical and economical points.