阅读说明：本技术 一种大型不锈钢电渣重熔钢锭的化学成分控制方法 (Chemical composition control method for large stainless steel electroslag remelting steel ingot ) 是由 李奇 石佳毅 朱孝渭 陈文君 花小龙 于 2019-10-30 设计创作，主要内容包括：本发明涉及钢锭化学成分控制技术领域,公开了一种大型不锈钢电渣重熔钢锭的化学成分控制方法,所述控制方法包括如下步骤：步骤一、结晶器准备,步骤二、通入干燥空气,步骤三、渣料准备,步骤四、造渣,步骤五、重熔,步骤六、脱锭。本发明首先控制自耗电极的化学成分,符合客户要求；其次使用和熔炼钢种相同钢种的钢板作为引锭板。最后在电渣重熔过程中向结晶器内投入脱氧剂,让脱氧剂本身和大量注入的干燥空气中的氧发生反应,保持熔渣的还原性,达到降低钢中易被氧化元素被氧化的可能性,从而保证在大流量干燥空气保护下钢锭各成分全部符合制造规范。具有投资小、成本低、容易实现的优点。(The invention relates to the technical field of chemical component control of steel ingots, and discloses a chemical component control method of a large stainless steel electroslag remelting steel ingot, which comprises the following steps: step one, crystallizer preparation, step two, dry air introduction, step three, slag charge preparation, step four, slagging, step five, remelting, step six, and ingot removal. The chemical components of the consumable electrode are controlled firstly, and the requirements of customers are met; and secondly, using a steel plate of the same steel type as that of the molten steel as a dummy bar. And finally, a deoxidizer is put into the crystallizer in the electroslag remelting process, the deoxidizer reacts with oxygen in a large amount of injected dry air, the reducibility of the slag is kept, the possibility that the easily oxidized elements in the steel are oxidized is reduced, and therefore all components of the steel ingot meet the manufacturing specifications under the protection of large-flow dry air. Has the advantages of small investment, low cost and easy realization.)

1. A chemical composition control method for a large stainless steel electroslag remelting steel ingot is characterized by comprising the following steps:

step one, preparing a crystallizer, and paving a plate of the same steel type at the bottom as a dummy bar;

secondly, introducing dry air, and introducing the dry air into the device ten minutes before electrifying;

step three, preparing slag, namely proportioning the slag by using AH phi-8;

fourthly, slagging, namely adding the prepared slag into the bottom of a crystallizer, and electrifying and striking an arc in the crystallizer by using a graphite electrode;

step five, remelting, namely hanging a graphite electrode out after all slag materials are melted, replacing a consumable electrode for remelting, and adding Si-Ca alloy and aluminum wires every five minutes for deoxidation during remelting;

and sixthly, stripping ingots, namely stripping ingots 6 hours after electroslag remelting is finished, and cleaning the surfaces of the steel ingots.

2. The method for controlling chemical composition of the large stainless steel electroslag remelting ingot according to claim 1, wherein in the second step, the flow rate of the drying gas is 900-1000 cubic meters per hour.

3. The method for controlling chemical components of the large stainless steel electroslag remelting ingot according to claim 1 or 2, wherein in the second step, the preparation method of the dry air is as follows:

A. preparing gas, namely generating sufficient gas by an air compressor;

B. gas treatment, namely drying gas generated by an air compressor through a refrigerator, and then performing oil-gas separation through an oil-gas separator;

C. and (4) gas storage, namely introducing the treated gas into a gas bag for storage.

4. The method for controlling the chemical components of the large stainless steel electroslag remelting ingot according to claim 1, wherein in the third step, the AH phi-8 ratio of the components is as follows: 65% of fluorite, 20% of white corundum and 15% of lime.

5. The method for controlling chemical composition of the large stainless steel electroslag remelting ingot according to claim 1, wherein in the fifth step, the length deviation of the consumable electrode is less than or equal to 10 mm.

6. The method for controlling chemical composition of a large stainless steel electroslag remelting ingot according to claim 1 or 5, wherein in step five, the consumable electrode is baked with coal gas before use, the baking time is 4 hours or more, and the baking temperature is 700 ℃ or more.

7. The method for controlling chemical compositions of the large stainless steel electroslag remelting ingot according to claim 1, wherein in the fifth step, the addition amount of the Si-Ca alloy is 50-1500g/5 min, and the addition amount of the aluminum wire is 100-1100g/5 min.

Technical Field

The invention relates to the technical field of chemical component control of steel ingots, in particular to a chemical component control method of large stainless steel electroslag remelting steel ingots.

Background

The national nuclear power technology company arranges a CAP1400 main pipeline development subject in a national major scientific and technical special equipment manufacturing project, establishes a subject group which takes Bohai ship rework of a medium ship rework group company as a lead unit and takes a heavy company, China one and China two as subject member units, and develops a domestic development and attack of the CAP1400 main pipeline. The upper heavy casting forging undertakes the smelting and forging process of the main pipeline large forging straight pipe blank. The steel has the characteristics of high purity requirement, huge weight (hundred tons), high chemical component requirement (16.0-18.0% of Cr, 11.0-14.0% of Ni, less than 0.005% of As, Sn, Sb and Pb) and high mechanical performance index.

The existing electroslag remelting equipment for upper recasting and forging is a semi-open electroslag furnace, and dry air is used as an air source of a gas protection system, so that the influence of atmosphere in the remelting process can be reduced to the minimum. But because of the existence of the dry air, the whole furnace is in a strong oxidation state during smelting. How to ensure that active elements such as Cr, Ni and the like are not burnt in a strongly-oxidized smelting atmosphere, and meanwhile, the purity of molten steel is kept, and the content of harmful elements is controlled has great difficulty.

Disclosure of Invention

The invention provides a chemical component control method for a large stainless steel electroslag remelting steel ingot, and solves the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a chemical composition control method for a large stainless steel electroslag remelting steel ingot comprises the following steps:

step one, preparing a crystallizer, and paving a plate of the same steel type at the bottom as a dummy bar;

secondly, introducing dry air, and introducing the dry air into the device ten minutes before electrifying;

step three, preparing slag, namely proportioning the slag by using AH phi-8;

fourthly, slagging, namely adding the prepared slag into the bottom of a crystallizer, and electrifying and striking an arc in the crystallizer by using a graphite electrode;

step five, remelting, namely hanging a graphite electrode out after all slag materials are melted, replacing a consumable electrode for remelting, and adding Si-Ca alloy and aluminum wires every five minutes for deoxidation during remelting;

and sixthly, stripping ingots, namely stripping ingots 6 hours after electroslag remelting is finished, and cleaning the surfaces of the steel ingots.

As a preferred technical scheme of the invention, in the second step, the flow rate of the drying gas is 900-.

As a preferred technical solution of the present invention, in the second step, the preparation method of the dry air is as follows:

A. preparing gas, namely generating sufficient gas by an air compressor;

B. gas treatment, namely drying gas generated by an air compressor through a refrigerator, and then performing oil-gas separation through an oil-gas separator;

C. and (4) gas storage, namely introducing the treated gas into a gas bag for storage.

As a preferred technical scheme of the present invention, in the third step, the components in the ratio of AH phi-8 are: 65% of fluorite, 20% of white corundum and 15% of lime.

In a preferred embodiment of the present invention, in the fifth step, the length deviation of the consumable electrode is 10mm or less.

In a preferred technical scheme of the invention, in the fifth step, the consumable electrode is baked by coal gas before use, the baking time is more than or equal to 4 hours, and the baking temperature is more than or equal to 700 ℃.

As a preferred technical scheme of the invention, in the fifth step, the adding amount of the Si-Ca alloy is 50-1500g/5 min, and the adding amount of the aluminum wire is 100-1100g/5 min.

The invention has the following advantages:

the chemical components of the consumable electrode are controlled firstly, and the requirements of customers are met; and secondly, using a steel plate of the same steel type as that of the molten steel as a dummy bar. And finally, a deoxidizer is put into the crystallizer in the electroslag remelting process, the deoxidizer reacts with oxygen in a large amount of injected dry air, the reducibility of the slag is kept, the possibility that the easily oxidized elements in the steel are oxidized is reduced, and therefore all components of the steel ingot meet the manufacturing specifications under the protection of large-flow dry air. Has the advantages of small investment, low cost and easy realization.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a flow chart of a chemical composition control method for a large stainless steel electroslag remelting steel ingot.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, a chemical composition control method for a large stainless steel electroslag remelting ingot comprises the following steps:

step one, preparing a crystallizer, wherein the crystallizer adopts a three-phase bipolar series electroslag furnace; a copper wall water-cooled crystallizer and a water-cooled bottom plate are adopted, and a same steel plate is laid at the bottom to be used as a dummy bar plate;

secondly, introducing dry air, introducing the dry air into the device ten minutes before electrifying, wherein the flow of the dry air is 900 plus 1000 cubic meters per hour, and the preparation method of the dry air comprises the following steps:

A. preparing gas, namely generating sufficient gas by an air compressor;

B. gas treatment, namely drying gas generated by an air compressor through a refrigerator, and then performing oil-gas separation through an oil-gas separator;

C. gas storage, namely introducing the treated gas into a gas bag for storage;

step three, preparing slag charge, namely proportioning the slag charge by adopting AH phi-8, wherein the AH phi-8 comprises the following components in proportion: fluorite 65% -white corundum 20% -lime 15%;

step four, slagging, namely adjusting the flow rate of drying air in the crystallizer, wherein the introduced flow rate of the drying air is 700 plus 800 cubic meters per hour, adding part of prepared slag into the bottom of the crystallizer, electrifying and striking an arc in the crystallizer by using a graphite electrode, and gradually adding all the slag into the crystallizer until the slag is completely melted;

step five, remelting, namely hanging out a graphite electrode after all slag materials are melted, adjusting the pressure of drying air in a crystallizer to enable the flow rate of the drying air to be 800 cubic meters per hour, replacing a consumable electrode for remelting, wherein the length deviation of the consumable electrode is less than or equal to 10mm, the length of a single support is 2500 +/-10 mm, the consumable electrode is baked by coal gas before being used, the baking time is more than or equal to 4 hours, the baking temperature is more than or equal to 700 ℃, Si-Ca alloy and aluminum wires are added every five minutes for deoxidation during remelting, the adding amount of the Si-Ca alloy is 50-1500g/5 minutes, and the adding amount of the aluminum wires is 100 minus one minute and 1100g/5 minutes; hanging the alloy ingot out when the alloy ingot is melted to be 50 +/-50 mm away from the top end of the consumable electrode, replacing another pair of consumable electrodes for continuous remelting, and reducing electric power and transferring to final feeding operation when the actual weight of the electroslag ingot is remelted to be 8 tons less than the preset weight;

the consumable electrode meets the requirements of table 1:

TABLE 1

And sixthly, stripping ingots, namely stripping ingots 6 hours after electroslag remelting is finished, and cleaning the surfaces of the steel ingots.

The invention adopts a dry air protection electroslag remelting method to manufacture a high-purity TP316 large stainless steel electroslag remelting steel ingot which is used for a nuclear power main pipeline and has the weight of more than 100 tons, and the components of the steel ingot meet the following table 2:

TABLE 2

The chemical components of the consumable electrode are controlled firstly, and the requirements of customers are met; and secondly, using a steel plate of the same steel type as that of the molten steel as a dummy bar. And finally, a deoxidizer is put into the crystallizer in the electroslag remelting process, the deoxidizer reacts with oxygen in a large amount of injected dry air, the reducibility of the slag is kept, the possibility that the easily oxidized elements in the steel are oxidized is reduced, and therefore all components of the steel ingot meet the manufacturing specifications under the protection of large-flow dry air. Has the advantages of small investment, low cost and easy realization.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.