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CN-122012937-A - Ultra-pure gear steel inclusion removal method based on interface activation energy regulation and control

CN122012937ACN 122012937 ACN122012937 ACN 122012937ACN-122012937-A

Abstract

The invention discloses an ultra-pure gear steel inclusion removal method based on interface activation energy regulation and control, and belongs to the technical field of electroslag remelting. The surface quality control of the electrode cast ingot comprises uniformly smearing an antioxidation coating on the surface of the electrode cast ingot, electroslag system proportioning, current-voltage gradient control, electroslag furnace gas atmosphere control, and deep removal of harmful inclusions such as Al2O3, tiN and the like by optimizing electrode components, slag system design and dynamic process control. The ultra-pure gear steel produced by the invention has uniform chemical components, can effectively remove the inclusions in the cast ingot, and reduces the total amount of the inclusions.

Inventors

  • MA CHAO
  • DUAN LUZHAO
  • XU YUBIN
  • ZHANG FULI
  • WANG YUFEI
  • GUO RUIHUA
  • LV XIAONING
  • QI ZIYANG

Assignees

  • 河北河钢材料技术研究院有限公司
  • 河钢集团有限公司
  • 河钢股份有限公司

Dates

Publication Date
20260512
Application Date
20260119

Claims (9)

  1. 1. The method for removing the inclusion of the ultra-pure gear steel based on interface activation energy regulation is characterized by comprising the following steps of: (1) Controlling the surface quality of the electrode cast ingot, namely controlling the chemical components of the electrode cast ingot and coating an antioxidation coating; (2) Proportioning and preprocessing electroslag system, namely heating the electroslag remelting system to 900-1000 ℃ from room temperature, and preserving heat for 4-5 hours; (3) The current-voltage gradient control is that the current-voltage is dynamically controlled in four sections in the electroslag remelting process; (4) And controlling the atmosphere of the gas in the electroslag furnace, namely protecting the whole process by argon and dynamically regulating the flow.
  2. 2. The method for removing the inclusion of the ultra-pure gear steel based on the interface activation energy regulation and control of the method for removing the inclusion of the gear steel based on the interface activation energy is characterized in that the special slag system in the step (2) comprises, by mass, 8-10% of CaF 2 ：48～56%、CaO：20～28%、MgO：1～2%、Al 2 O 3 ：3～8%、TiO 2 .
  3. 3. The method for removing the ultra-pure gear steel inclusions based on the interface activation energy regulation and control of claim 1, wherein in the step (2), the viscosity of an electroslag system at 1500 ℃ is 0.015-0.020Pa.S, the viscosity at 1600 ℃ is 0.018-0.025 Pa.S, the interface activation energy of slag system and target inclusions (Al 2 O 3 , tiN) is regulated and controlled to an optimal range, the interface activation energy of Al 2 O 3 is 120-150 kJ/mol, and the interface activation energy of TiN is 150-180 kJ/mol.
  4. 4. The ultra-pure gear steel inclusion removal method based on interface activation energy regulation and control of claim 1 is characterized in that in the step (3), four-stage dynamic control is specifically performed by the steps of arc starting phase voltage 20-25V, current 1.6-1.8 kA, slag melting phase voltage 25-28V, current 1.6-2.4 kA, remelting phase voltage 30-35V, current 2.4-2.7 kA, feeding phase voltage 18-20V and current 2.0-2.6 kA.
  5. 5. The method for removing the ultra-pure gear steel inclusions based on interface activation energy regulation and control according to claim 1, wherein in the step (4), dynamic argon flow is controlled to be 220-260L/min in an arcing period and a slagging period, 150-180L/min in a remelting period and 100-150L/min in a feeding period.
  6. 6. The method for removing the inclusion of the ultra-pure gear steel based on the interface activation energy regulation and control of the step (1) is characterized in that the antioxidation coating in the step (1) is a nano yttrium oxide dispersion strengthening aluminate coating, the thickness of the coating is 0.2-0.5 mm, the content of nano yttrium oxide is 4-9%, and the particle size range of nano yttrium oxide particles is 10-100 nm.
  7. 7. The method for removing impurities from ultra-pure gear steel based on interface activation energy regulation according to any one of claims 1 to 6, wherein in the step (1), the chemical composition of the electrode ingot is controlled to ：C：0.15～0.22%、Si：0.15～0.25%、Mn：0.65～0.95%、P≤0.0030%、S≤0.0020%、Cr：0.85～1.15%、Ni：0.40～0.5%、Al：0.015～0.055%、Nb：0.015～0.030%、Mo：0.11～0.15%, by mass percent, and the balance is Fe and unavoidable impurities.
  8. 8. The method for removing the inclusion of the ultra-pure gear steel based on the interface activation energy regulation and control according to any one of claims 1 to 6, wherein the number density of the inclusion of the ultra-pure gear steel electroslag ingot obtained by the method is less than or equal to 4.06/mm 2 , the number of the inclusion is reduced by more than 30%, the number density of the TiN of the electroslag ingot is less than or equal to 2.1/mm 2 , and the TiN removal rate is more than 40%.
  9. 9. The method for removing the inclusion of the ultra-pure gear steel based on the interface activation energy regulation and control according to any one of claims 1 to 6, wherein the total oxygen content of molten steel is stably controlled below 10ppm, and the titanium element yield is above 92%.

Description

Ultra-pure gear steel inclusion removal method based on interface activation energy regulation and control Technical Field The invention belongs to the technical field of electroslag remelting, and particularly relates to an ultra-pure gear steel inclusion removal method based on interface activation energy regulation. Background Gear steel is widely used for manufacturing automobile gearboxes, wind power gearboxes and aerospace transmission systems. With the development of society and technology, higher requirements are put on the fatigue strength and wear resistance of gear steel. Inclusions such as Al 2O3 and TiN in the gear steel can cause stress concentration, so that fatigue fracture is caused, and the service life of the gear is restricted. In industrial production, the technology of modifying the inclusion treated by calcium, optimizing refining slag system, protecting casting and the like is generally adopted. The calcium treatment can convert Al 2O3 into low-melting-point calcium aluminate, but the practical effect is limited by various conditions, and is difficult to thoroughly eliminate micron-sized inclusions, the high-alkalinity refining slag has a certain adsorption capacity on oxides, but has no effect on removing TiN, and the protection casting can effectively reduce secondary oxidation of molten steel, but cannot avoid the problem of segregation of inclusions in the solidification process. In addition, the above means has a removal rate of less than 50% for inclusions having a size of less than 20. Mu.m, particularly TiN inclusions having a size of 1 to 5. Mu.m. Electroslag remelting (ESR) is used as a refining means of high-end special steel and high-temperature alloy, and can realize inclusion removal, tissue densification and chemical component fine adjustment. However, the traditional electroslag remelting process has obvious limitations in smelting ultra-pure gear steel, namely, on one hand, the slag system design pertinence is insufficient, the conventional CaF 2-CaO-Al2O3 ternary slag system has limited Al 2O3 removal capability, the titanium element yield is low, the interfacial activation energy between the slag system and Al 2O3 and TiN inclusion is high, the wettability is poor, and the effective adsorption removal is difficult. On one hand, the process control window is wide, the fixed current-voltage mode is easy to cause the over-deep molten pool and the disturbance of the temperature field, and the floating path and time of the inclusions are limited. On the one hand, the atmosphere protection is not matched with the melting speed. The simple whole-course constant-current argon protection mode can not dynamically inhibit the atmosphere fluctuation in different remelting stages, and can possibly cause secondary oxidation of molten steel to generate new TiN or Al 2O3 inclusions. Therefore, an innovative electroslag remelting method is needed in the art, and slag components can be optimized fundamentally to reduce interface energy barriers to harmful inclusions, and dynamic cooperative control of current, voltage parameters and atmosphere protection is realized, so that inclusions in gear steel are removed efficiently, and severe requirements of high-end equipment on material purity are met. Disclosure of Invention The invention provides an ultra-pure gear steel inclusion removal method based on interface activation energy regulation and control, which aims to solve the problems of low removal efficiency, large fluctuation of titanium yield, rough process control and the like of gear steel Al 2O3, tiN and the like in the traditional electroslag remelting, and realizes inclusion depth removal through dynamic combined control of slag components, electric parameters and atmosphere. In order to achieve the effect, the technical scheme adopted by the invention is that the method for removing the electroslag remelting inclusion depth of the ultra-pure gear steel based on interface activation energy regulation comprises the following steps: (1) Controlling the surface quality of the electrode cast ingot, namely controlling the chemical components of the electrode cast ingot and coating an antioxidation coating; (2) Proportioning and preprocessing electroslag system, namely heating the electroslag remelting system to 900-1000 ℃ from room temperature, and preserving heat for 4-5 hours; (3) The current-voltage gradient control is that the current-voltage is dynamically controlled in four sections in the electroslag remelting process; (4) And controlling the atmosphere of the gas in the electroslag furnace, namely protecting the whole process by argon and dynamically regulating the flow. The special slag system in the step (2) comprises, by mass, 8-10% of CaF 2：48～56%、CaO：20～28%、MgO：1～2%、Al2O3：3～8%、TiO2. In the step (2), the viscosity of the electroslag system at 1500 ℃ is 0.015-0.020Pa.S, the viscosity at 1600 ℃ is 0.018-0.025 Pa.S, and the interface activation energy of slag metal betwe