阅读说明：本技术 用于含铝钛镍基高温合金的基础渣系及电渣重熔方法 (Basic slag system for aluminum-titanium-containing nickel-based high-temperature alloy and electroslag remelting method ) 是由 曾莉 徐芳泓 王岩 谷宇 张威 于 2019-11-21 设计创作，主要内容包括：本发明属于电渣重熔冶炼技术领域,具体涉及一种用于含铝钛镍基高温合金的基础渣系及电渣重熔方法。所述用于含铝钛镍基高温合金的基础渣系,按重量百分比计,包括：CaF<Sub>2</Sub> 40％-50％、CaO 13％-24％、MgO 4％-10％及余量的Al<Sub>2</Sub>O<Sub>3</Sub>和TiO<Sub>2</Sub>。本发明的用于含铝钛镍基高温合金的基础渣系根据电极坯中Al、Ti元素的实际值,使元素的烧损或增加量得到有效控制,最终满足标准要求,并且使电渣锭表面质量显著改善。(The invention belongs to the technical field of electroslag remelting smelting, and particularly relates to a basic slag system for an aluminum-titanium-containing nickel-based high-temperature alloy and an electroslag remelting method. The basic slag system for the aluminum-titanium-containing nickel-based high-temperature alloy comprises the following components in percentage by weight: CaF 2 40-50 percent of CaO, 13-24 percent of CaO, 4-10 percent of MgO and the balance of Al 2 O 3 And TiO 2 . The basic slag system for the aluminum-titanium-containing nickel-based high-temperature alloy disclosed by the invention enables the burning loss or the increment of elements to be effectively controlled according to the actual values of Al and Ti elements in an electrode blank, finally meets the standard requirement, and enables the surface quality of an electroslag ingot to be remarkably improved.)

1. A basic slag system for aluminum-containing titanium-nickel-base superalloy, comprising, by weight: CaF₂40-50 percent of CaO, 13-24 percent of CaO, 4-10 percent of MgO and the balance of Al₂O₃And TiO₂。

2. The basic slag system of claim 1, comprising, in weight percent: CaF₂43-47%, CaO 16-20%, MgO 5-8% and the rest Al₂O₃And TiO₂Wherein, TiO₂≤10％。

3. The basic slag system of claim 2, comprising, in weight percent: CaF₂45 percent of CaO18 percent, 6 percent of MgO and the balance of Al₂O₃And TiO₂Wherein, TiO₂≤10％。

4. The basic slag system of any one of claims 1 to 3, wherein the TiO is₂The content of (b) is calculated by the following formula:

TiO₂content (%) - (D)_i×0.9/400)×(2.5×ln(100×(Al/Ti)))/Ti(％)

Wherein D is_iThe diameter of the cross section of the electroslag ingot is mm;

al is the actual content of aluminum in the electrode blank,%;

ti is the actual content of titanium in the electrode blank.

5. The basic slag system according to claim 4, wherein the content of titanium in the electrode blank is 4 times or more the content of aluminum.

6. The basic slag system of claim 4, whereinCharacterized in that when said TiO is₂When the calculated content of (A) is more than 10%, the TiO₂The content value of (A) is 10%.

7. The basic slag system of claim 1, wherein the Al is₂O₃And TiO₂The equivalent grain diameter is less than or equal to 2 mm.

8. The basic slag system according to claim 4, wherein the diameter of the electroslag ingot is not less than 400 mm.

9. An electroslag remelting process, characterised in that a basic slag system for aluminium-titanium-containing nickel-base superalloys according to any of claims 1-8 is formulated in the slag preparation phase.

Technical Field

The invention belongs to the technical field of electroslag remelting smelting, and particularly relates to a basic slag system for an aluminum-titanium-containing nickel-based high-temperature alloy and an electroslag remelting method.

Background

Electroslag remelting is a process of melting, refining and solidifying and forming a metal consumable electrode in a crystallizer by using resistance heat generated by liquid slag. The electroslag steel has the advantages of pure metal, compact structure, uniform components, excellent performance and the like, and the electroslag remelting technology is an important means for producing special alloy materials from the generation to the present.

The production process of the electroslag remelting nickel-based superalloy has a series of advantages of strong impurity removing capability, strong S removing capability, improvement of cast ingot solidification structure and the like. For common-grade to high-end grade nickel-base superalloys, electroslag remelting may be used as the second or final manufacturing step. The nickel-based high-temperature alloys widely used at present all contain a certain amount of Al and Ti elements. Al and Ti are easy-to-burn elements, and burning behaviors are mutually restricted, especially when the ratio of Ti to Al in the alloy is large, Al and Ti in the electroslag remelting process are difficult to control, and electroslag ingot components are easy to be incompatible.

The actual contents of Al and Ti in the initial electrode blank also have an uncontrollable influence on the electroslag process. For example: adopting the same slag system, wherein Al in the initial electrode blank is 0.06 percent, Ti in the initial electrode blank is 1.2 percent, after electroslag remelting, Al in the electroslag ingot is 0.25 percent, Ti in the electroslag ingot is 0.54 percent, Al and Ti are sintered, and both Al and Ti are out of the standard range; when the initial electrode blank contains 0.21% of Al and 1.15% of Ti, after electroslag remelting, the electroslag ingot contains 0.15% of Al and 0.67% of Ti, which belong to the condition that Al and Ti are both sintered. Therefore, the tiny change of the actual content of Al and Ti in the initial electrode blank can produce completely different influences on the electroslag process, simultaneously, quite high requirements are put forward on the smelting component precision of the electrode blank, and the diameter size of the electroslag ingot can also produce influences on element burning loss, so the action mechanism is quite complex.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a basic slag system for an aluminum-titanium-containing nickel-based high-temperature alloy and an electroslag remelting method.

In one aspect, the invention provides a basic slag system for an aluminum-titanium-containing nickel-based superalloy, comprising, by weight: CaF₂40-50 percent of CaO, 13-24 percent of CaO, 4-10 percent of MgO and the balance of Al₂O₃And TiO₂。

The basic slag system comprises the following components in percentage by weight: CaF₂43-47 percent of CaO, 16-20 percent of CaO, 5-8 percent of MgO and the balance of Al₂O₃And TiO₂Wherein, TiO₂≤10％。

The basic slag system comprises the following components in percentage by weight: CaF₂45 percent of CaO, 18 percent of MgO, 6 percent of MgO and the balance of Al₂O₃And TiO₂Wherein, TiO₂≤10％。

The basic slag system described above, said TiO₂The content calculation method is as follows:

TiO₂content (%) - (D)_i×0.9/400)×(2.5×ln(100×(Al/Ti)))/Ti(％)

Wherein D is_iThe diameter of the cross section of the electroslag ingot is mm;

al is the actual content of aluminum in the electrode blank,%;

ti is the actual content of titanium in the electrode blank.

In the basic slag system, the content of titanium in the electrode blank is more than 4 times of the content of aluminum.

The basic slag system as described above, when said TiO₂When the calculated content of (A) is more than 10%, the TiO₂The content value of (A) is 10%.

The basic slag system described above, said Al₂O₃And TiO₂The equivalent grain diameter is less than or equal to 2 mm.

In the basic slag system, the diameter of the electroslag ingot is more than or equal to 400 mm.

In another aspect, the invention provides an electroslag remelting method, wherein the basic slag system for the aluminum-titanium-containing nickel-base superalloy is prepared in a slag preparation stage.

The technical scheme of the invention has the following beneficial effects:

(1) the basic slag system and the electroslag remelting method for the aluminum-titanium-containing nickel-based high-temperature alloy are suitable for the alloy with a larger Ti/Al content ratio (Ti/Al is more than or equal to 4.0) of an electrode blank;

(2) the basic slag system for the aluminum-titanium-containing nickel-based high-temperature alloy disclosed by the invention has the advantages that according to the actual values of Al and Ti elements in an electrode blank, the burning loss or the increment of the elements are effectively controlled, the standard requirements are finally met, and the surface quality of an electroslag ingot is obviously improved;

(3) the basic slag system for the aluminum-titanium-containing nickel-based high-temperature alloy has good fluidity and proper viscosity, and ensures that an electroslag ingot has good ingot surface quality;

(4) the basic slag system for the aluminum-titanium-containing nickel-based high-temperature alloy has higher density, and metal molten drops pass through the slag system in the electroslag remelting process, so that impurities are removed.

Detailed Description

The present invention will be described in detail with reference to the following embodiments in order to fully understand the objects, features and effects of the invention. The process of the present invention employs conventional methods or apparatus in the art, except as described below. The following noun terms have meanings commonly understood by those skilled in the art unless otherwise specified.

A basic slag system for aluminum-titanium-containing nickel-base superalloy comprises the following components in percentage by weight: CaF₂40-50 percent of CaO, 13-24 percent of CaO, 4-10 percent of MgO and the balance of Al₂O₃And TiO₂。

The basic slag system of the aluminum-titanium-containing nickel-based superalloy is preferably CaF₂43-47%, CaO 16-20%, MgO 5-8% and the rest Al₂O₃And TiO₂Wherein, TiO₂≤10％。

The basic slag system for the aluminum-titanium-containing nickel-based superalloy is more preferably, the basic slag system for the aluminum-titanium-containing nickel-based superalloy comprises the following components in percentage by weight: CaF₂45 percent of CaO, 18 percent of MgO, 6 percent of MgO and the balance of Al₂O₃And TiO₂Wherein, TiO₂≤10％。

The basic slag system for the aluminum-titanium-containing nickel-based high-temperature alloy is a five-element system, and the base slag system comprises the following components in parts by weight:

CaF₂: as an adjuvant, the melting point, viscosity and surface tension of the slag can be reduced, but the CaF is comparable to other components₂The conductivity of (2) is higher;

CaO: the slag alkalinity is increased by adding CaO into the slag, the desulfurization efficiency is improved, and the conductivity of the slag can be reduced by adding CaO;

MgO: the slag contains proper MgO, so that a layer of semi-solidified film can be formed on the surface of the slag pool, the hydrogen absorption of the slag pool can be prevented, and the transmission of the oxygen supply to the metal molten pool by the valence oxide in the slag can be prevented, so that the contents of oxygen, hydrogen and nitrogen in the ingot can be reduced, and meanwhile, the heat loss of the surface of the slag to the atmosphere radiation can be reduced by the solidified film;

Al₂O₃: can obviously reduce the electrical conductivity of the slag, reduce the power consumption and improve the productivity, but Al in the slag₂O₃The increase will increase the melting temperature and viscosity of the slag and will reduce the desulfurization effect of the slag, and in addition, the remelting process will be difficult to establish and stabilize;

TiO₂: with Al in the slag system₂O₃And Al and Ti form a certain equilibrium relation, e.g. without TiO₂Ti and Al in the electrode blank₂O₃The reaction makes the burning loss of Ti uncontrollable and Al₂O₃The excessive Al content is caused by the massive reduction of Al. Thus TiO₂The amount of addition is particularly critical.

The basic slag system for the aluminum-titanium-containing nickel-based superalloy plays a synergistic role in the electroslag remelting process, and particularly, CaF₂CaO and MgO are basic compositions of the slag system, so that the slag system has proper melting point, resistivity, viscosity and the like, and basic applicability to the nickel-based alloy. Al (Al)₂O₃And TiO₂The addition of (A) mainly plays a certain thermodynamic equilibrium relationship with Al and Ti elements in a slag system, if TiO is not added₂Ti and Al in the electrode blank₂O₃The reaction makes the burning loss of Ti uncontrollable and Al₂O₃The excessive Al content is caused by the massive reduction of Al. Al (Al)₂O₃And TiO₂The method mainly plays a role in effectively controlling the burning loss of aluminum and titanium elements.

Preferably, the TiO is₂The content calculation method is as follows:

TiO₂content (%) - (D)_i×0.9/400)×(2.5×ln(100×(Al/Ti)))/Ti(％)

Wherein，D_iThe diameter of the cross section of the electroslag ingot is mm;

al is the actual content of aluminum in the electrode blank,%;

ti is the actual content of titanium in the electrode blank.

Wherein, the electroslag ingot is cylindrical.

Preferably, the content of titanium in the electrode blank is more than 4 times of the content of aluminum, and can be expressed as Ti/Al ≥ 4.0, wherein Ti/Al is the content of titanium in the electrode blank divided by the content of aluminum, and more preferably, the content of titanium in the electrode blank is 4 times to 20 times of the content of aluminum.

If the titanium content in the electrode blank is less than 4 times the aluminum content, Al, which is not suitable for the basic slag system of the present invention₂O₃And TiO₂The Al and Ti elements in the slag system can not form a thermodynamic equilibrium relationship, and the surface quality of the electroslag ingot is deteriorated.

Preferably, when said TiO is₂When the calculated content of (A) is more than 10%, the TiO₂The content value of (A) is 10%. In the basic slag system of the aluminum-containing titanium-nickel-based high-temperature alloy, TiO₂Is less than 10%, thereby realizing effective control of Al and Ti burning loss and achieving the expected target. However, when TiO₂When the content of (A) is 10%, the burning loss control effect reaches a maximum limit value, and when TiO is further added₂When the amount is contained, the surface quality of the electroslag ingot is rapidly deteriorated.

Preferably, the Al is₂O₃And TiO₂The equivalent particle size is less than or equal to 2mm, wherein the equivalent particle size is a geometric equivalent particle size.

Because of the influence of size effect, the solidification process of the electroslag ingot is related to the size of the electroslag ingot, when the diameter of the cross section of the electroslag ingot is less than 400mm, a slag system is not accurately controlled, and qualified electroslag ingot can be obtained by randomly allocating one slag system according to the basic slag system proportion limited by the invention.

However, when the diameter of the cross section of the electroslag ingot is more than or equal to 400mm, the preferable basic slag system proportion of the invention is needed.

In another aspect, the invention provides an electroslag remelting method, wherein the electroslag remelting method is used for preparing the basic slag system for the aluminum-titanium-containing nickel-base superalloy in the slag preparation stage

The electroslag remelting method of the present invention is performed by a conventional production process, and the present invention is not limited specifically herein.

Preferably, in the electroslag remelting method, the melting speed is controlled to be 6-8 Kg/min.

The basic slag system for the aluminum-titanium-containing nickel-based high-temperature alloy and the electroslag remelting method effectively control the burning loss or the increasing amount of elements according to the actual values of Al and Ti elements in an electrode blank, finally meet the standard requirements, and obviously improve the surface quality of an electroslag ingot.