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Grain refiner for ferritic stainless steel continuous casting and preparing method and using method of grain refiner

A grain refiner, stainless steel technology, applied in the field of grain refiner for ferritic stainless steel continuous casting, to achieve the effect of significant grain refinement and reduction of columnar crystal ratio

Active Publication Date: 2017-08-04
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention aims at the lack of grain refiner used in the stainless steel continuous casting production process and its addition method in the prior art, and aims to provide a grain refiner for continuous casting of ferritic stainless steel and its preparation and Method of use for ferritic stainless steel continuous casting process

Method used

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  • Grain refiner for ferritic stainless steel continuous casting and preparing method and using method of grain refiner
  • Grain refiner for ferritic stainless steel continuous casting and preparing method and using method of grain refiner
  • Grain refiner for ferritic stainless steel continuous casting and preparing method and using method of grain refiner

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preparation example Construction

[0022] The preparation method of the grain refiner for continuous casting of ferritic stainless steel provided by the embodiment of the present invention specifically includes the following steps:

[0023] (1) Abrasives: Grinding the large-grained TiC prepared by the carbothermal reduction method in a planetary mill until the average particle size is less than 1 μm to obtain micron-sized TiC powder;

[0024] Carbothermal reduction method: with TiO 2 and carbon black as raw materials, after high-energy ball milling, put it into a tube furnace protected by argon flow and heat it to 1259 ° C ~ 1500 ° C, and keep it for 1 hour. As a result, a near-stoichiometric TiC powder with a grain size of about 80 nm was obtained.

[0025] Grinding: the rotation speed of the ball mill is 425r / min, and the ball milling time is 25min.

[0026] Planetary Mill Model: QMSB-4 Planetary High Energy Ball Mill

[0027] (2) Mixing: Weigh the obtained micron-sized TiC powder and Fe powder with a part...

Embodiment 1

[0034] Effect of grain refiner on microstructure of 430L ferritic stainless steel

[0035] Such as figure 1 As shown, from the metallographic structure, it can be found that TiC as a grain refiner can significantly increase the ratio of equiaxed grains in the steel structure, and the number of small grains increases. When the TiC content is 0.03%, the refining effect is the best. When When the TiC content continues to increase, the refinement effect basically does not change.

[0036] From figure 2It can be seen from the figure that the number of acicular ferrite increases with the increase of TiC content, and the size decreases continuously. When the TiC content reaches 0.03%, it presents the optimal state, and the acicular ferrite is fine and dense, showing the split grain State, play a role in refining the grain. When the amount of TiC added reaches 0.05%, the change of ferrite morphology and quantity is not obvious, which is basically similar to that of 0.03%.

Embodiment 2

[0038] Effect of grain refiner on grain size of 430L ferritic stainless steel

[0039] In the continuous casting tundish, a grain refiner was thrown into the molten steel, and its addition amount was 300 g per ton of steel. The comparison example was 430L continuous casting molten steel without throwing the grain refiner. After the smelted cast steel sample is cut, coarsely ground, finely ground, and polished, the grain boundaries are corroded. The corrosion solution is 10% oxalic acid solution for electrolysis, the corrosion voltage is 5V, and the corrosion time is 40-60s.

[0040] figure 1 (a), figure 1 (b) Typical metallographic pictures of steel samples with TiC as grain refiner and steel samples without grain refiner. Carl Zeiss metallographic microscope was used for observation, and the intercept point method in "GBT6394-2002 Metal Average Grain Size Determination Method" was used to obtain the grain size of samples with different components and contents, as shown in ...

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Abstract

The invention discloses a grain refiner for ferritic stainless steel continuous casting. The grain refiner comprises, by weight percentage, 0.01%-0.05% of TiC powder and 99.95%-99.99% of pure Fe powder; the grain size of the TiC powder is smaller than 1 micrometer, the grain size of the pure Fe powder ranges from 10 micrometers to 20 micrometers, and the density of particles of the TiC powder in the grain refiner is larger than 20000 units / mm<3>. The preparing method of the grain refiner includes the following steps that (1) material grinding is carried out, wherein large-particle TiC prepared through a carbon thermal reduction process is placed into a planetary mill to be ground, grinding is carried out until the mean grain size is smaller than 1 micrometer, and micron order TiC powder is obtained; (2) even mixing is carried out, wherein the obtained micron order TiC powder and the pure Fe powder with the grain size ranging from 10 micrometers to 20 micrometers are weighed according to the weight percentages of the raw materials to be placed into a ball mill for even mixing; and (3) hot isostatic pressure molding is carried out, wherein mixed powder obtained after even mixing in the step (2) is subject to hot isostatic pressure molding. During ferritic stainless steel continuous casting production, the grain refiner is added, the proportion of columnar crystals of a ferritic stainless steel continuous casting blank is greatly reduced, the isometric crystal proportion is improved to 70% or above, and the grain refinement effect is remarkable.

Description

technical field [0001] The invention relates to the technical field of grain refinement of metal materials, in particular to a grain refiner for continuous casting of ferritic stainless steel and a preparation and use method thereof. Background technique [0002] Stainless steel refers to the general term for alloy steel that is resistant to corrosion by the atmosphere, acid, alkali and salt. Because of its unique rust resistance, corrosion resistance, heat resistance, low temperature toughness, bioneutrality, chemical compatibility, decoration, manufacturability, long life, recyclability and many other advantages, it has been widely used in The demand in various fields of industry, agriculture, national defense and people's daily life is also increasing year by year. In 2015, the national stainless steel production has reached 22 million tons. According to the alloy elements and microstructure, it can be divided into: ferritic stainless steel, austenitic stainless steel, m...

Claims

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Application Information

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IPC IPC(8): B22D11/108C21C7/00C22C33/02C22C38/14
CPCB22D11/108C21C7/0006C22C33/0264C22C38/14
Inventor 李阳杜鹏飞姜周华徐光杨光吕建波秦国清陈常勇姚丛林
Owner NORTHEASTERN UNIV
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