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Free-cutting corrosion-resistant steel and preparation method thereof

A technology of corrosion-resistant steel and free-cutting steel, applied in the field of steelmaking technology, can solve the problems of not taking into account the corrosion-resistant high-nitrogen stainless steel's free-cutting performance, large particle inclusions, pitting corrosion, etc.

Active Publication Date: 2021-05-14
UNIV OF SCI & TECH BEIJING
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  • Abstract
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  • Claims
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Problems solved by technology

[0003] Chinese patent application CN112195419A discloses a method for preparing corrosion-resistant high-nitrogen stainless steel. This patent application mainly studies the heat treatment of steel. Through heat treatment in a high-nitrogen environment, the steel can obtain the technical effects of corrosion resistance and non-passivation , but it did not design the entire smelting process, nor did it take into account the easy-cutting performance of corrosion-resistant high-nitrogen stainless steel
Chinese patent application CN112176151A discloses a method for controlling the morphology of MnS inclusions in free-cutting steel. This patent application focuses on the study of free-cutting properties, and relies on bismuth treatment to control the morphology of manganese sulfide, and gives the free-cutting steel. Composition design and production process design, but it does not take into account the improvement of the corrosion resistance of free-cutting steel
Chinese patent application CN111850407A discloses 850MPa grade titanium-containing free-cutting stainless steel forged bar and its preparation method. Its composition design and production process plan, but it pays more attention to the improvement of the strength of the steel, and the patent application mainly relies on titanium treatment to modify the sulfide in the steel and control the form of the sulfide, but when the sulfur content is less than At 0.3%, this titanium treatment needs to rely on nitrogen as a protective gas. When argon is used as a protective gas, titanium treatment cannot change the form of manganese sulfide, and the form of manganese sulfide cannot be effectively controlled and it is easy to cause pitting corrosion of steel, thus affecting Corrosion resistance; when this titanium treatment method uses nitrogen as a protective gas, the nitrogen content in the steel is not easy to control, and if the nitrogen content in the steel is too high, it is easy to generate large particle inclusions, which will affect the free cutting performance of the steel

Method used

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  • Free-cutting corrosion-resistant steel and preparation method thereof

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preparation example Construction

[0046] In a second aspect, the present invention provides a method for preparing the free-cutting corrosion-resistant steel described in the first aspect of the present invention, said method comprising the steps of:

[0047] (1) Mix the free-cutting steel (such as free-cutting nib steel), ferrochrome mixture and slag evenly to obtain steel material; the free-cutting steel contains the following components in mass percentage: C, 0.02%~0.04 % (such as 0.02%, 0.03% or 0.04%); Si, 0.05%~0.15% (such as 0.05%, 0.08%, 0.1%, 0.12% or 0.15%); Mn, 1.4%~1.6% (such as 1.4%, 1.5% or 1.6%); S, 0.32% to 0.38% (such as 0.32%, 0.35% or 0.38%); P, 0.03% to 0.06% (such as 0.03%, 0.04%, 0.05% or 0.06%); Mo, 2%~2.2% (such as 2%, 2.1% or 2.2%); the balance is Fe and unavoidable impurities; in the present invention, the mass percentage of Fe in the free-cutting steel can be, for example, 95% ~96%, the mass percentage of the inevitable impurities in the free-cutting steel is less than 1%; in the pr...

Embodiment 1

[0069]In this example, the prepared free-cutting corrosion-resistant steel contains the following components in terms of mass percentage: C, 0.02%; Si, 0.45%; Mn, 1.2%; S, 0.26%; P, 0.02%; Mo, 1.6%; Cr, 19.5%; Ca, 0.05%; Mg, 0.01%; , ω[Te] / ω[S]=0.077.

[0070] In this example, a vertical tubular silicon-molybdenum resistance furnace (high-temperature tubular furnace) is used for smelting. The specific operation process is: batching→melting in a high-temperature tubular furnace→adding tellurium→sampling, specifically including the following process:

[0071] Ingredients: Use a cutting machine to cut the finished free-cutting steel wire rod into free-cutting steel blocks with a length of 50mm, weigh 100g of free-cutting steel block samples and put them into a crucible (MgO crucible); weigh 33g of ferrochromium mixture, and weigh 12.5g of slag, adding 12.5g of slag and 33g of ferrochrome mixture into the crucible and mixing to obtain steel; 0.028%; Si, 0.1%; Mn, 1.6%; S, 0.35%;...

Embodiment 2

[0085] In this example, the prepared free-cutting corrosion-resistant steel contains the following components in terms of mass percentage: C, 0.021%; Si, 0.46%; Mn, 1.2%; S, 0.26%; P, 0.02%; Mo, 1.6%; Cr, 19.5%; Ca, 0.05%; Mg, 0.01%; , ω[Te] / ω[S]=0.077.

[0086] In this example, a vertical tubular silicon-molybdenum resistance furnace (high-temperature tubular furnace) is used for smelting. The specific operation process is: batching→melting in a high-temperature tubular furnace→adding tellurium→sampling, specifically including the following process:

[0087] Ingredients: Use a cutting machine to cut the finished free-cutting steel wire rod into free-cutting steel blocks with a length of 50mm, weigh 100g of free-cutting steel block samples and put them into a crucible (MgO crucible); weigh 33g of ferrochromium mixture, and weigh 12.5g of slag, adding 12.5g of slag and 33g of ferrochrome mixture into the crucible and mixing to obtain steel; 0.028%; Si, 0.1%; Mn, 1.6%; S, 0.35...

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Abstract

The invention relates to free-cutting corrosion-resistant steel and a preparation method thereof. The free-cutting corrosion-resistant steel comprises the following components in percentage by mass: 0.015 to 0.024 percent of C; 0.4 to 0.5 percent of Si; 1.2 to 1.3 percent of Mn; 0.24 to 0.3 percent of S; 0.02 to 0.03 percent of P; 1.5 to 1.75 percent of Mo; 19 to 20 percent of Cr; 0.03 to 0.08 percent of Ca; 0.01 to 0.02 percent of Mg; 0.02 to 0.05 percent of Al; 0.012 to 0.03 percent of Te; and the balance Fe and impurities. The method comprises the following steps of uniformly mixing free-cutting steel, a ferrochrome mixture and slag charge, and completely melting at high temperature to obtain a melt; and adding tellurium into the melt, conducting heat preservation treatment, and cooling to obtain the free-cutting corrosion-resistant steel. The free-cutting corrosion-resistant steel disclosed by the invention has the optimal component proportion, and has the comprehensive optimal free-cutting performance and corrosion resistance.

Description

technical field [0001] The invention belongs to the technical field of steelmaking technology, and in particular relates to a free-cutting corrosion-resistant steel and a preparation method thereof. Background technique [0002] Free-cutting steel occupies a large proportion in my country's steel market, especially in recent years, its consumption has been increasing, and it is mainly used in the automotive field. The development of free-cutting steel has a long history, which can be traced back to the First World War. By chance, Americans discovered that high-sulfur steel has good cutting performance. Since then, the research on free-cutting steel has begun. The free-cutting elements in free-cutting steel Or the compound formed by easy-cutting elements can reduce the resistance of the tool during the cutting process, lubricate the tool, and then improve the cutting performance. Sulfur is currently the most widely used easy-cutting element, and manganese sulfide is the most ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/60C22C38/22C22C38/06C22C33/04
CPCC22C33/04C22C38/002C22C38/02C22C38/04C22C38/06C22C38/22C22C38/60
Inventor 刘威杨树峰宋朝琦李京社陈赛
Owner UNIV OF SCI & TECH BEIJING
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