Technology for processing CrNiMo series steel material

Abstract

The invention discloses a technology for processing a CrNiMo series steel material. The technology comprises the steps of adopting an electroslag remelting technology to obtain a steel ingot which contains 0.14-0.19% of C, 1.5-1.8% of Cr, 0.17-0.35% of Si, 0.4-0.6% of Mn, 0.25-0.36% of Mo, 1.4-1.7% of Ni, 0-0.035% of P and 0-0.030% of S according to percent by weight, forging the steel ingot, then carrying out normalizing and high temperature tempering, carburizing, high temperature tempering and oil quenching, and finally, carrying out low temperature tempering to complete the processing. According to the technology, a heat treatment processing technology which is simple and easy to operate is utilized to ensure the product quality, the problem that a loading part of a coal machine fails to work is solved, the service life of a product is prolonged, and the producing and processing costs are lowered.

Description

technical field [0001] The invention relates to a steel processing method, in particular to a processing technology for CrNiMo series steel materials used for processing gears, and belongs to the technical field of metal material processing. Background technique [0002] The most widely used heavy-duty gears of domestic coal machinery are high-hardenability carburized steel CrNiW. Because CrNiW series steel has high hardenability, good wear resistance, and high contact fatigue and bending fatigue resistance, it has been used all the time. It is used in heavy-duty gears of coal mining machinery and other major bearing parts of large machinery, such as high-speed diesel engines, aircraft engine crankshafts, gear sets, flanges, etc. However, in the extremely harsh working environment under the mine, the bearing parts often have to bear large impact loads and transmission power. The bearing parts using this material have obvious limitations. For example, the shearer gears often ...

AI Technical Summary

Problems solved by technology

However, in the extremely harsh working environment under the mine, the bearing parts often have to bear large impact loads and transmission power. The bearing parts using this material have obvious limitations. For example, the shearer gears often break in the actual use of coal mines. The early failure of the shearer traveling box; the traveling wheel of the shearer traveling box often fails early under the harsh mining conditions of high strength and high load, and the service life cannot meet the expectation. The failure forms are usually: broken teeth, deep wear of Surface pitting and tooth surface gluing, among which tooth fracture is the most fatal, followed by deep wear

The impact, jamming, excessive wear, and sudden tooth breakage of the traveling wheels during the traveling process have seriously affected the quality and working efficiency of the shearer.

At the same time, the price of this material is high, and the heat treatment process is too complicated, so the cost of heat treatment is also very high.

[0003] The applicant found after analyzing the heat treatment process and combining the actual use conditions: (1) Although the CrNiW material has relatively good wear resistance, it also has high contact fatigue and bending fatigue resistance, but due to the extremely hardenability of the material Well, in addition, the carbon content of the raw materials is basically at the upper limit. After carburizing and quenching, the hardness of the core is too high, which reduces the toughness and plasticity indicators, which leads to the early failure of the shearer in the actual use of coal mines; ( 2) The heat treatment process of CrNiW is complicated. Its pre-heat treatment adopts normalizing + one or more tempering. After quenching, it needs multiple high-temperature tempering to control austenite. However, it is difficult to control the amount of residual austenite after repeated heating and cooling.

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