Low-silicon microalloyed high-temperature carburized gear steel and manufacturing method thereof

Abstract

The invention discloses low-silicon microalloyed high-temperature carburized gear steel and a manufacturing method thereof. The manufacturing method includes the steps that about 20% of scrap steel isadded into a converter, then molten iron is added for smelting, final steel tapping control targets are that C is larger than or equal to 0.08% and P is smaller than or equal to 0.015%, sliding plateslag stopping operation is conducted in the steel tapping process, and discharged slag is reduced; and alloying is started about 90 seconds after tapping is started, and ferro-aluminum, carbon powder, an alloy and lime are added in sequence. According to the low-silicon microalloyed high-temperature carburized gear steel and the manufacturing method thereof, enrichment of inclusions at the innerside of a gate is greatly reduced, steady-state control over a stopper curve in the casting process is achieved, involving of large-size inclusions due to the fact that the stopper curve suddenly fluctuates is avoided, continuous casting production of at least six furnaces can be achieved, and meanwhile the service fatigue life of a gear is remarkably prolonged; and abnormal growth of austenite grains is hindered, and the austenite grain coarsening temperature of the gear steel is increased, so that the effects of preventing mixed grains and coarse grains of the austenite grains of the gear steel after high carburizing temperature are achieved.

Description

technical field [0001] The invention relates to the technical field of special steels, in particular to a low-silicon micro-alloyed high-temperature carburizing gear steel and a manufacturing method thereof. Background technique [0002] With the increasing environmental pollution and energy depletion, the high-temperature vacuum carburizing technology with environmental protection, energy saving, high performance and high efficiency has become the main direction of the development and application of international heat treatment technology in recent years. At present, the gas carburizing temperature commonly used at home and abroad is generally not higher than 930°C, while the high-temperature vacuum carburizing can be as high as 980°C or even 1000°C because of its oxygen-free treatment environment. According to the calculation of the carburizing principle, the carburizing temperature can be increased by about 53°C, and the carburizing time can be shortened by about 50%. Th...

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Problems solved by technology

[0005] Aiming at the deficiencies of the prior art, the present invention provides a low-silicon micro-alloyed high-temperature carburized gear steel and its manufacturing method, which solves the problem of mixed crystals and coarse grains in the austenite grains of the gear steel after high carburizing temperature The problem