Method for preparing double-scanning and spray forming high-speed steel under purification

Abstract

The invention belongs to the material processing field and relates to a method for preparing double-scanning and spray forming high-speed steel under purification. First, a yttria partially stabilized zirconia ceramic filter is adopted to filter high-speed molten steel that is molten and refined in vacuum atmosphere; before the spray forming of the molten steel, gas washing operation is conducted on a working chamber and an atomizer chamber and high purity nitrogen is filled in the working chamber and the atomizer chamber with gas pressure close to 1atm; the uniformly refined high-speed molten steel is slowly poured into a heated pouring box, through which the molten steel is filtered; and through a draft tube, the molten steel is atomized into melt drip that is deposited on a depositor to form deposition blank. When the temperature of the deposition blank is lower than 200 DEG C, the deposition blank is taken out. In each step of operation of spray deposition, the method reduces harmful ceramic particles and oxides to be mixed in as well as the content of unfavorable elements such as gas, thus not only solving the segregation problem of the high-speed steel, but also improving the purity of the high-speed steel.

Description

technical field [0001] The invention belongs to the field of material processing. It relates to a method for purifying and preparing double-scanning spray-formed high-speed steel. Background technique [0002] The spray forming process is mainly composed of three continuous processes of alloy melt atomization, droplet flight and cooling, and deposition blank growth. At the end of the draft tube, the alloy melt is broken into a large number of fine droplets with a size ranging from a few microns to hundreds of microns by the atomized airflow. The molten droplets are accelerated by the high-speed airflow, and at the same time perform rapid heat exchange with the airflow (cooling rate up to 10 3 ~10 6 K / S). Due to the difference in cooling rate, the molten droplets smaller than a certain critical size condense into solid particles before reaching the deposition body, the larger ones may still be liquid, and the intermediate-sized ones are semi-solidified particles containin...

AI Technical Summary

Problems solved by technology

They used a high-speed steel to test and showed that the superplastic temperature range of spray-formed high-speed steel was wide, and at a higher strain rate (1×10 -1 S -1 ), there is still a high temperature tensile elongation of more than 100%, which is much higher than the plasticity of the high-speed steel prepared by the conventional ingot forging process under the same conditions. However, the inclusions inside the high-speed steel prepared by this method high content