Smelting method for improving quality of 20CrMnTi gear steel continuous casting molten steel

Abstract

The invention discloses a smelting method for improving quality of 20CrMnTi gear steel continuous casting molten steel. The smelting method comprises the following steps that 1, 30% or above of molteniron is added into a LF refining electric furnace; 2, lime is added as a slag material, and it is guaranteed that in the whole smelting process of the electric furnace, foaming slag submerged arc operation is adopted; 3, the C content of the tapped molten steel is controlled to be greater than or equal to 0.05%, the P content of the tapped molten steel is controlled to be less than or equal to 0.010%, and the temperature is controlled to be higher than 1630 DEG C; 4, silicon and manganese alloy and medium carbon and chromium alloy are added to a steel ladle before tapping, and baking is conducted; 5, tapping side deoxidation is conducted; 6, the tapping time of a tapping hole of the electric furnace is controlled to be longer than 110 seconds; 7, after tapping is completed, argon gas blowing is quickly adjusted to soft blowing; and 8, the deoxidation rules are that aluminum residue balls and calcium carbide are added before tapping, and silicon-calcium-barium and aluminum-iron-steel are added after 20 tons of the molten steel is tapped, wherein the tapping time is 140+ / -10 seconds. By means of the smelting method, the smelting process is optimized; chemical components, the aluminum content and deoxidation are strictly controlled, so that the smelting time of the refining furnace is shortened; quality of the molten steel and quality of a continuous casting blank are improved; and it is guaranteed that the continuous casting, purity, the grain size and the banded structure of the steel are all qualified.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, in particular to a smelting method for improving the quality of molten steel for continuous casting of 20CrMnTi gear steel. Background technique [0002] Gear steel is generally low-carbon, low-alloy high-quality or high-grade high-quality structural steel, and its working conditions are: [0003] (1) When the gear steel is working, the entire tooth surface from the meshing point to the tooth root is subjected to pulsating bending stress, and the maximum bending stress is caused on the dangerous end surface of the tooth root, which can cause bending fatigue damage to the gear, and the damage form It's a broken tooth. [0004] (2) When the gear is working, the power is transmitted through contact. Under the repeated contact stress, contact fatigue damage will occur on the working tooth surface. The main damage forms are pitting and magnetization peeling. [0005] (3) When the gear steel is w...

AI Technical Summary

Problems solved by technology

[0010] 2. Difficult to control chemical elements

Due to the low carbon content of the electric furnace and the peroxidation of the molten steel, it is difficult to produce slag in refining. The carbon element in the slag of the primary refining furnace is difficult to control. The actual refined product has high carbon, which directly affects the hardenability of the gear steel. The titanium composition of molten steel is controlled. large fluctuations

[0013] 3. Long smelting time

[0015] 4. High oxygen content in steel