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A nitrogen-controlled pouring method and pouring system for nitrogen-containing steel ingots

A pouring method and pouring system technology, applied in the field of casting technology, can solve problems such as increased content, difficult control, and inapplicability

Active Publication Date: 2019-04-30
TIANJIN HEAVY EQUIP ENG RES +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Before the molten steel is poured, the chemical composition of the molten steel is firstly controlled by refining, and the mass fractions of [C], [Mn], [Cr], [Ni], [Mo], [H], [O], [N] elements are respectively After the molten steel smelting is completed, the contents of [H] elements, [O] elements and [N] elements in the molten steel will inevitably increase during the transportation and pouring process; the above vacuum pouring method can better remove [H] element, [O] element and [N] element, it is difficult to control [H] element and [O] element in molten steel by using the above atmospheric pouring method
However, for the manufacture of steel ingots with low [H] element, low [O] element and high [N] element content, such as ultra-supercritical rotor steel ingots, the above two methods are not up to the requirements, so they are not applicable

Method used

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  • A nitrogen-controlled pouring method and pouring system for nitrogen-containing steel ingots
  • A nitrogen-controlled pouring method and pouring system for nitrogen-containing steel ingots
  • A nitrogen-controlled pouring method and pouring system for nitrogen-containing steel ingots

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Experimental program
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Effect test

Embodiment 1

[0034] First, according to the gating system structure, such as figure 1 As shown, install each facility. It includes a tundish 2, a vacuum cover 3, a vacuum tank 6 and a steel ingot mold 4, wherein the molten steel 1 is placed in the tundish 2, the steel ingot mold 4 is placed in the vacuum tank 6, the vacuum tank 6, the vacuum cover 3 and the The tundishes 2 are connected by flanges, and are sealed against each other by gravity to form a sealed space.

[0035] The second step is to control the composition of the pouring molten steel. The content of [N] element in the pouring molten steel is not adjusted. The final gas element content of the pouring molten steel is as follows: [H]=0.00022%, [O]=0.0049%, [N]= 0.0060%.

[0036] The third step is to open the first valve 8, vacuumize the vacuum tank 6 through the vacuum system, and close the first valve 8 when the vacuum reaches 70Pa; open the second valve 19, and use the nitrogen bus system 5 to vacuum the tank 6. Charge nitr...

Embodiment 2

[0040] First, according to the gating system structure, such as figure 1 As shown, install each facility. It includes a tundish 2, a vacuum cover 3, a vacuum tank 6 and a steel ingot mold 4, wherein the molten steel 1 is placed in the tundish 2, the steel ingot mold 4 is placed in the vacuum tank 6, the vacuum tank 6, the vacuum cover 3 and the The tundishes 2 are connected by flanges, and are sealed against each other by gravity to form a sealed space.

[0041] The second step is to control the composition of molten steel for pouring, adjust the [N] element content in molten steel for pouring molten steel, and the final gas element content of pouring molten steel is as follows: [H]=0.00016%, [O]=0.0042%, [N]=0.0347 %.

[0042] The third step is to open the first valve 8, vacuumize the vacuum tank 6 through the vacuum system, and close the first valve 8 when the vacuum reaches 150 Pa; open the second valve 19, and use the nitrogen bus system 5 to vacuum the tank 6. Charge n...

Embodiment 3

[0046] When pouring ultra-supercritical rotor steel ingots, the ultra-supercritical rotor steel ingots require that the [H] element content in molten steel be less than or equal to 0.00015%, the [O] element content be less than or equal to 0.0030%, and the [N] element content be 0.045-0.060%.

[0047] First, according to the gating system structure, such as figure 1 As shown, install each facility. It includes a tundish 2, a vacuum cover 3, a vacuum tank 6 and a steel ingot mold 4, wherein the molten steel 1 is placed in the tundish 2, the steel ingot mold 4 is placed in the vacuum tank 6, the vacuum tank 6, the vacuum cover 3 and the The tundishes 2 are connected by flanges, and are sealed against each other by gravity to form a sealed space.

[0048] The second step is to control the composition of molten steel for pouring, adjust the [N] element content in molten steel for pouring molten steel, and the final gas element content of pouring molten steel is as follows: [H]=0....

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Abstract

The invention relates to a control nitrogen pouring method and system for steel ingots containing nitrogen. The method includes the steps that steel ingot molds are placed into a vacuum chamber, the vacuum chamber is filled with nitrogen after vacuum pumping, and thus the pressure inside and outside the vacuum chamber can be balanced; and molten steel is poured into the steel ingot molds under the nitrogen protective atmosphere to be solidified and cooled, so that the steel ingots are formed. The pouring system comprises a vacuum tank (6), the steel ingot molds (4) placed in the vacuum tank (6), and a tundish (2) arranged above the vacuum tank (6). A steel tapping hole of the tundish (2) communicates with a steel pouring opening of each steel ingot mold (4). The upper end of a tundish core bar (9) is connected with a nitrogen cylinder (12). The vacuum tank (6) is connected with a vacuum system and a nitrogen busbar system (5). By the adoption of the method and system, the content of [N] in the molten steel can be guaranteed to meet the specification requirement in the pouring process, and meanwhile [H] and [O] elements in the molten steel can be removed.

Description

technical field [0001] The invention relates to the technical field of casting technology, in particular to a nitrogen-controlled pouring method and a pouring system for nitrogen-containing steel ingots. Background technique [0002] At present, the pouring methods of large steel ingots are mainly divided into vacuum pouring and atmospheric pouring. Among them, vacuum pouring is to complete pouring in a vacuum chamber to maintain a certain degree of vacuum in the surrounding environment of molten steel, so that [H] elements, [O] elements and [N] elements can be better removed from molten steel; atmospheric pouring is done in the atmosphere. Generally, the pouring flow is protected by gas. The effect of this method on removing [H] elements, [O] elements and [N] elements in steel is average, and even the molten steel may absorb [H] elements and [O] elements due to improper operation. ]element. [0003] Before the molten steel is poured, the chemical composition of the molten...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22D7/00B22D23/00B22D1/00
CPCB22D1/002B22D7/00B22D23/00
Inventor 李金良王欢胡建东高建军蔚志奎
Owner TIANJIN HEAVY EQUIP ENG RES