A method for controlling the nitrogen content of 20crmnti series gear steels produced by electric furnace process with high steel scrap ratio

A control method and scrap steel ratio technology, applied in the field of metallurgy, can solve the problems of difficult control of nitrogen content, long electric furnace smelting cycle, slow smelting rhythm, etc., achieve good surface quality, significant economic and social benefits, and improve the effect of purity

Active Publication Date: 2021-11-23
ZENITH STEEL GROUP CORP CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] For raw materials with a high ratio of scrap steel (scrap steel accounts for more than 70%), due to the slow smelting rhythm and the long electric furnace smelting cycle, the nitrogen absorption is relatively high during the electric furnace smelting process. Therefore, it is relatively difficult to control the nitrogen content to N<60ppm

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] (1) The electric furnace adds scrap steel and molten iron steelmaking raw materials for low-drawing carbon smelting. Scrap steel accounts for 90% of the total weight of steelmaking raw materials, and molten iron accounts for 10% of the total weight of steelmaking raw materials. The total charge is 112t / furnace, and the electric furnace smelting cycle 49 minutes, the tapping temperature is 1638°C, the binary basicity of the electric furnace slag is controlled to 2.9, the tapping [C] is 0.05%, the tapping [P] is 0.009%, and 2.6 kg of ferrosilicon is added sequentially with the steel flow at 1 / 3 of the tapping / t, low-carbon ferromanganese 12kg / t, low-carbon ferrochrome 18.5kg / t, deoxidizer aluminum block 20kg / furnace, low-carbon recarburizer 80kg / furnace and lime 550kg / furnace, low nitrogen (N≤1000ppm) Slag 300kg / furnace, tapping time is 3.6min;

[0034] (2) The LF refining furnace is well sealed to ensure a reducing atmosphere in the furnace. Silicon carbide 1.8kg / t and ...

Embodiment 2

[0038] Tapping [C]: 0.04%, tapping temperature 1641°C, feeding pure calcium wire 80m / furnace, hanging ladle temperature after soft blowing, continuous pouring heat 1568°C, superheat 27°C, other operations are the same as in Example 1 .

Embodiment 3

[0040] Tapping [C]: 0.06%, tapping temperature 1645°C, vacuum holding time 15min, other operations are the same as in Example 2.

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Abstract

The invention discloses a method for controlling the nitrogen content of 20CrMnTi series gear steels produced by an electric furnace process with a high steel scrap ratio. Its composition by weight percentage is C: 0.17~0.23%, Si: 0.17~0.37%, Mn: 0.80~1.10%, P≤0.030%, S≤0.030%, Cr: 1.00~1.30%, Al: 0.010~0.040 %, Ti: 0.04-0.10%, the rest is Fe and unavoidable impurities. The present invention reasonably controls the tapping carbon and tapping temperature of the electric furnace, selects a reasonable process route and key parameters, optimizes the addition of tapping aluminum block and slag, optimizes the refining operation process, and adopts argon sealing and overall tundish for continuous casting. In this way, while the nitrogen content is effectively reduced, the technical indicators such as the purity, hardenability, and oxygen content of the gear steel are guaranteed, and the technical requirements of high-grade gear steel users are fully met.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for controlling the nitrogen content of 20CrMnTi series gear steels with high steel scrap ratio produced by an electric furnace process. Background technique [0002] 20CrMnTi series gear steel is the most commonly used low-carbon carburizing steel in China at present, and its consumption is relatively large, accounting for more than 50% of the total consumption of domestic gear steel. Due to the high hardenability of this steel, it has a hard and wear-resistant surface and a tough core after carburizing and quenching. It has high low-temperature impact toughness, good welding performance, good processing performance, and small processing deformation. , very good fatigue resistance, good machinability after normalizing, etc., widely used in the manufacture of important parts that withstand high speed, medium or heavy loads, impact and friction in machines,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/06C22C38/28C22C33/06C21C5/54C21C7/06C21C7/00C21C7/10B22D11/111B22D11/115B22D41/58B22D41/18
CPCB22D11/111B22D11/115B22D41/18B22D41/58C21C5/54C21C7/0056C21C7/0087C21C7/06C21C7/10C22C33/06C22C38/02C22C38/04C22C38/06C22C38/28Y02P10/20
Inventor 豆乃远朱富强任振海陈占领李亚刘泽杨刘威李俊杰徐必靖
Owner ZENITH STEEL GROUP CORP CO LTD
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