WO2015072660A1

WO2015072660A1 - Ni-based superalloy and manufacturing method therefor

Info

Publication number: WO2015072660A1
Application number: PCT/KR2014/008792
Authority: WO
Inventors: 강황진
Original assignee: 주식회사 엔아이비
Priority date: 2013-11-13
Filing date: 2014-09-22
Publication date: 2015-05-21

Abstract

The present invention relates to a Ni-based superalloy and a manufacturing method therefor. The Ni-based superalloy of the present invention consists of: 0.08-0.20% by weight of C; 12-14% by weight of Cr; 3.8-5.2% by weight of Mo; 1.8-2.8% by weight of Nb; 5.5-6.5% by weight of Al; 0.5-1.0% by weight of Ti; 0.005-0.015% by weight of B; 0.05-0.15% by weight of Zr; and 0.01-1.0% by weight of Ca, Y or a combination thereof; and the remainder being Ni and inevitable impurities. The manufacturing method for a Ni-based superalloy according to the present invention comprises: a step for melting Ni by any one of melting methods of high-frequency induction heating, arc melting, plasma heating and electron beam melting; and a step for adding the respective additive elements and uniformly dispersing the same.

Description

NI Base Superalloy and Manufacturing Method Thereof

The present invention relates to a Ni-based superalloy and a manufacturing method thereof.

Ni-based superalloy is a material that is used at high temperature above 800 ℃ and its tensile strength, yield strength and elongation at high temperature do not show a big difference from that at room temperature, and it has excellent high temperature creep characteristics and high oxidation resistance at high temperature. have. Recently, a material that can be used even in a high temperature environment of 1500 ° C. or more has been developed, and various materials have been applied according to a use temperature and a use. The material of grade 800 ℃ is the most used super alloy, and is applied to many parts of automobile turbocharger system. Automotive turbochargers are effective in improving torque and reducing displacement of automobiles. Recently, the use of turbochargers for automobiles is increasing the use of superalloys for the engine downsizing. In addition, as the application of the turbocharger to the passenger car segment has been expanded, it is necessary to improve the service endurance temperature from 800 to 900 ° C for gasoline engines and 900 to 1,000 ° C for gasoline engines. Accordingly, materials such as Inconel 713C or GR235, which have been generally applied to 800 to 900 ° C, need to be changed to higher grade materials such as Mar246 or MarM 247, resulting in increased cost.

Table 1 below shows the composition of Inconel 713C, Inconel 713LC, Mar246, MarM 247 and GR235.

Table 1

	C	Cr	Ni	Co	Mo	W	Nb	Ta	Ti	Al	B	Zr	Hf	Fe	Tm (℃)
In713C	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06			1260-1288
In713LC	0.06	12	Bal	-	4.3	-	2	-	0.7	5.8	0.007	0.06			1288 ~ 1321
MarM246	0.15	9	Bal	10	2.5	10	-	1.5	1.5	5.5	0.015	0.05			1315 ~ 1343
MarM247	0.16	8.2	Bal	10	0.6	10	-	3	One	5.5	0.015	-	1.5		1305-1365
GMR235	0.15	15.5	Bal	-	5.3	-	-	-	-	3	0.06	-	-	10

Referring to Table 1, MarM 246 and MarM 247 further include high melting point metal elements such as Ta, W, and Hf in existing materials to improve high temperature strength, high temperature creep and oxidation resistance. However, since the elements are expensive, the manufacturing cost is increased.

Korean Patent Laid-Open Publication No. 2001-0108041 discloses a die casting product composed of nickel or cobalt-based superalloy, which has a fine average particle size compared to a wireless microstructure and investment casting product.

Korean Patent Laid-Open No. 2001-0007520 has a mass% of C: 0.1% or less, Si: 2% or less, Mn: 2% or less, S: 0.005% or less, Cr: 10-25%, Al: 2.1-4.5% Less than or equal to N: 0.08% or less, and at least one of B: 0.03% or less, Zr: 0.2% or less and Hf: 0.8% or less in total, 0.001 to 1%, Mo: 0.01 to 15%, and W: Ni base heat resistant alloy containing 2.5-15% in total of 1 or more types of 0.01-9% is disclosed.

It is an object of the present invention to provide a Ni-based superalloy that can be applied at 900 ° C or higher, which is the operating temperature of a gasoline engine, by improving high temperature strength, improving oxidation resistance and creep rupture strength.

In order to achieve the above object, the present invention provides a Ni-based superalloy in which a small amount of inexpensive Y and Ca is added to a conventional Inconel 713C component. Specifically, the present invention is C: 0.08 to 0.20 wt%, Cr: 12 to 14 wt%, Mo: 3.8 to 5.2 wt%, Nb: 1.8 to 2.8 wt%, Al: 5.5 to 6.5 wt%, Ti: 0.5 to Ni-based superalloy comprising 1.0 wt%, B: 0.005 to 0.015 wt%, Zr: 0.05 to 0.15 wt%, Ca, Y or a combination of these elements: 0.01 to 1.0 wt%, the balance being Ni and inevitable impurities. to provide.

Preferably, Ca may be added as CaO, and Y may be added as Y ₂ O ₃ .

The present invention also provides a turbocharger component made of a Ni-based superalloy having the above composition.

In addition, the present invention is C: 0.08 to 0.20% by weight, Cr: 12 to 14% by weight, Mo: 3.8 to 5.2% by weight, Nb: 1.8 to 2.8% by weight, Al: 5.5 to 6.5% by weight, Ti: 0.5 to 1.0 To prepare a Ni-based superalloy comprising a% by weight, B: 0.005 to 0.015% by weight, Zr: 0.05 to 0.15% by weight, Ca, Y or a combination of these elements: 0.01 to 1.0% by weight, the balance consisting of Ni and inevitable impurities Method of manufacturing a Ni-based superalloy comprising the steps of dissolving Ni in any one of the melting method of high frequency induction heating, arc melting, plasma heating and electron beam melting, and uniformly dispersing while adding each additional element. To provide.

The present invention can provide a Ni-based superalloy that is excellent in economical properties at high temperatures of 900 to 1000 ° C. required for gasoline engine parts, turbocharger parts, etc. of automobiles, and which is excellent in ductility and creep characteristics and oxidation resistance.

In addition, the present invention can be applied to agricultural machinery, sports and leisure vehicles, ships, yachts and aircraft parts as well as automobiles, it is possible to provide a Ni-based superalloy having excellent mechanical properties and economical.

All technical terms used in the present invention, unless defined otherwise, have the following definitions and conform to the meanings commonly understood by those skilled in the art in the relevant field of the present invention. Also described herein are preferred methods or samples, but similar or equivalent ones are within the scope of the present invention.

Throughout this specification, the terms including and including, unless included in the context, include a given step or component, or group of steps or components, but any other step or component, or step or component It should be understood that this group is not excluded.

Many components, such as turbine wheels, waste gate valves, and spindles, in turbocharger systems must be subjected to heat-resistant materials ranging from 900 ° C to 1,000 ° C. In the automotive industry, the most economical materials must be applied, and since the amount of use is considerably increased, an alloy composition considering economical properties is required for the same physical properties.

Expensive Ta, W, Hf, etc. are added to the conventional 1000 degreeC raw material, and it was not economically suitable as a raw material used for the automotive parts which need mass production. The present invention is a 900 to 800 ℃ class of C, Cr, Mo, Nb, Al, Ti, B, Zr and Ni by adding a low-cost Ca, Y or a mixture thereof having excellent high temperature characteristics and low cost It provides Ni-based superalloy that exhibits oxidation resistance at a high temperature of 1,000 ° C., and can economically mass-produce automotive turbochargers using the same.

Specifically, the present invention is C: 0.08 to 0.20% by weight, Cr: 12 to 14% by weight, Mo: 3.8 to 5.2% by weight, Nb: 1.8 to 2.8% by weight, Al: 5.5 to 6.5% by weight, Ti: 0.5 to 1.0 Ni group, characterized in that it comprises by weight, B: 0.005 to 0.015% by weight, Zr: 0.05 to 0.15% by weight, Ca, Y or a combination thereof: 0.01 to 1.0% by weight, the balance consisting of Ni and inevitable impurities Provide superalloy.

Hereinafter, the chemical composition and the effect of constituting the alloy of the present invention will be described.

C:

C is an element that is advantageous in order to form carbides such as MC, M7C3, M23C6, and M6C by combining with elements such as Nb, Ta, Mo, Cr, and the like to improve tensile strength and creep rupture strength required as heat resistant steel. However, when the content exceeds 0.20% by weight, not only the ductility and toughness of the alloy decreases significantly, but also the Al-containing Ni-based alloy can inhibit the alumina film formation. Therefore, the content of C is preferably 0.08 to 0.20% by weight.

Cr:

Cr is an element that functions as a solid solution strengthening element and has an oxidation resistance, and has an effect of uniformly producing an alumina film at the beginning of its production. It also forms carbides and contributes to the improvement of creep rupture strength. On the other hand, when the Cr content is excessively contained, on the contrary, the uniform production of the alumina film can be inhibited, and mechanical properties such as toughness and workability can be inhibited. Therefore, the content of Cr is preferably 12 to 14% by weight.

Mo:

Mo acts as a solid solution strengthening element, forms carbide to maintain high temperature strength, and strengthens austenite phase to increase creep rupture strength. Excessive content may cause the intermetallic compound, which is a factor of lowering toughness, to be precipitated and the carburization resistance may be lowered. Therefore, the content of Mo is preferably 3.8 to 5.2% by weight.

Nb:

Nb serves as a solid solution strengthening element, forms carbide to maintain high temperature strength, and contributes to the improvement of creep rupture strength as carbonitride, in addition to solid solution in austenite phase or γ 'phase. Therefore, the content of Nb is preferably 1.8 to 2.8% by weight.

Ti:

Ti is an element that promotes the precipitation of the γ 'phase of Ni ₃ (Al, Ti) to improve creep rupture strength and contribute to grain boundary strengthening. However, when it contains more than 1.0 weight%, γ 'phase will precipitate excessively and hot workability and weldability will remarkably worsen. Therefore, the content of Ti is preferably 0.5 to 1.0% by weight.

Al:

Al is an element that promotes the precipitation of the γ 'phase of Ni 3 (Al, Ti) to improve creep rupture strength and contribute to carbide formation. Therefore, the content of Al is preferably 5.5 to 6.5% by weight.

B, Zr:

These elements mainly contribute to grain refinement of the alloy, and contribute to the improvement of hot workability, weldability and creep characteristics. However, when it contains excessively, creep rupture strength fall. Therefore, the content of B is preferably 0.005 to 0.015% by weight, and the content of Zr is 0.05 to 0.15% by weight.

Y, Ca:

These elements are elements to impart the characteristics of the present invention, and are elements that fix S as a sulfide in a temperature range of 900 to 1000 ° C. to improve hot workability and improve high temperature strength and oxidation resistance. Y increases the ductility and tensile strength by miniaturizing particle size and layer spacing, and increases creep resistance, high temperature characteristics and oxidation resistance. When excessively adding Y, inclusions, such as an oxide, increase, and workability and weldability are impaired. Ca increases the grain boundary strength and improves hot workability. When Ca is added in excess, cleanliness is lowered, and hot workability and ductility are impaired. Y and Ca may be added alone 0.01 to 1.0% by weight. Preferably, 0.01 to 1.0% by weight of Y and Ca may be added in combination to improve the problem of excessive addition of Y and Ca, and to improve hot workability, creep resistance and high temperature characteristics.

In addition, the present invention is C: 0.08 to 0.20% by weight, Cr: 12 to 14% by weight, Mo: 3.8 to 5.2% by weight, Nb: 1.8 to 2.8% by weight, Al: 5.5 to 6.5% by weight, Ti: 0.5 to 1.0 Ni group, characterized in that it comprises by weight, B: 0.005 to 0.015% by weight, Zr: 0.05 to 0.15% by weight, Ca, Y or a combination thereof: 0.01 to 1.0% by weight, the balance consisting of Ni and inevitable impurities Provided are components for turbochargers made of superalloy. The turbocharger may be used in automobiles, ships, aircraft, agricultural machinery, and the like. The turbocharger component may be a turbine wheel, a turbine rotor or a waste gate valve.

In addition, the present invention is C: 0.08 to 0.20% by weight, Cr: 12 to 14% by weight, Mo: 3.8 to 5.2% by weight, Nb: 1.8 to 2.8% by weight, Al: 5.5 to 6.5% by weight, Ti: 0.5 to 1.0 To prepare a Ni-based superalloy comprising a weight%, B: 0.005 to 0.015% by weight, Zr: 0.05 to 0.15% by weight, Ca, Y or a combination thereof: 0.01 to 1.0% by weight, the balance consisting of Ni and inevitable impurities In the method, the Ni-based superalloy comprising the steps of dissolving Ni in any one of the high frequency induction heating, arc melting, plasma heating and electron beam melting method, and uniformly dispersing each addition element It is about.

실시예Example

Hereinafter, the present invention will be described in detail with reference to Examples.

Examples 1 to 5 are Ni-based superalloys with Y added, Examples 6 to 9 are Ni-based superalloys with Ca, and Examples 10 and 11 are Ni-based superalloys with both Y and Ca added. The comparative example is a conventional Ni-based superalloy in which Y and Ca are not added.

The compositions of Comparative Examples and Examples 1 to 11 are shown in Table 2.

TABLE 2

weight%	C	Cr	Ni	Co	Mo	W	Nb	Ta	Ti	Al	B	Zr	Y	Ca
Comparative Example 1	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	-	-
Example 1	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	0.05	-
Example 2	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	0.1	-
Example 3	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	0.3	-
Example 4	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	0.5	-
Example 5	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	1.0	-
Example 6	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	-	0.1
Example 7	0.1	13.5	bal	-	4.5	-	2	-	0.8	6	0.01	0.06	-	0.3
Example 8	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	-	0.5
Example 9	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	-	1.0
Example 10	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	0.25	0.25
Example 11	0.1	13.5	Bal	-	4.5	-	2	-	0.8	6	0.01	0.06	0.5	0.5

Table 3 shows the mechanical properties at high temperatures when the alloys were mixed and alloyed according to Examples 1 to 11 and Comparative Examples.

TABLE 3

	Sample Type	Tensile Strength (MPa) at 650 ℃	Yield strength (MPa) at 650 ℃	Elongation (%) at 650 ℃
Comparative Example 1	Inconel 713C Standard Specifications	840	700	6
Example 1	Inconel 713C + 0.05 Y	937	846	7.6
Example 2	Inconel 713C + 0.1 Y	960	866	11
Example 3	Inconel 713C + 0.3 Y	981	887	12
Example 4	Inconel 713C + 0.5 Y	985	870	6.8
Example 5	Inconel 713C + 1.0 Y	988	860	6.2
Example 6	Inconel 713C + 0.1 Ca	971	876	11.4
Example 7	Inconel 713C + 0.3 Ca	973	877	10.8
Example 8	Inconel 713C + 0.5 Ca	976	865	7.5
Example 9	Inconel 713C + 1.0 Ca	980	852	6.7
Example 10	Inconel713C + 0.25Y + 0.25Ca	982	871	7.3
Example 11	Inconel 713C + 0.5Y + 0.5Ca	990	875	6.2

As shown in Table 3, compared with the tensile strength, yield strength and elongation of Comparative Example 1, the tensile strength of Examples 1 to 11 is 937 to 990 MPa, the yield strength is 846 to 887 MPa and the elongation is 6.2 to 12 It can be seen that the improvement.

In tensile strength, Example 11 with both Y and Ca was found to be the most improved to 990 MPa. In yield strength, Example 3 with Y addition was found to be the most improved to 887 MPa. In elongation, Example 6 with Ca was most improved to 11.4. As a result, it can be seen that when both Y and Ca are added, both tensile strength and yield strength can be improved while maintaining an appropriate elongation.

Table 4

	Sample Type	Creep rupture temperature (℃) / stress (MPa)	Elongation at Break (%)	Break life (Hr)
Comparative Example 1	Inconel 713C Standard Specifications	980 ± 2/152	6	30
Example 2	Inconel 713C + 0.1 Y	980 ± 2/152	21.4	74
Example 4	Inconel 713C + 0.5 Y	980 ± 2/152	13.7	42.2
Example 6	Inconel 713C + 0.1 Ca	980 ± 2/152	14.3	62.4
Example 8	Inconel 713C + 0.5 Ca	980 ± 2/152	15	37.2

As shown in Table 4, Example 2 and Example 6, in which 0.1% of Y and 0.1% of Ca were added under the same creep rupture temperature and stress as in Comparative Example 1, respectively, were 21.4% and 14.3%, respectively. It can be seen that the excellent elongation at break and excellent break life of 74 hours and 62.4 hours, respectively. In addition, in the case of Examples 4 and 8 to which 0.5% of Y and 0.5% of Ca were added, it was also found that the elongation at break and the service life were higher than those of Comparative Example 1 (standard composition of Inconel 713C).

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

Claims

C: 0.08 to 0.20 wt%, Cr: 12 to 14 wt%, Mo: 3.8 to 5.2 wt%, Nb: 1.8 to 2.8 wt%, Al: 5.5 to 6.5 wt%, Ti: 0.5 to 1.0 wt%, B: A Ni-based superalloy comprising 0.005 to 0.015% by weight, Zr: 0.05 to 0.15% by weight, Ca, Y or a combination of these elements: 0.01 to 1.0% by weight, with the balance consisting of Ni and inevitable impurities.
The method of claim 1,

The Ca-based superalloy, wherein Ca is CaO, Y is added as Y 2 O 3 .
Turbocharged parts made of a Ni-based superalloy according to claim 1.
C: 0.08 to 0.20 wt%, Cr: 12 to 14 wt%, Mo: 3.8 to 5.2 wt%, Nb: 1.8 to 2.8 wt%, Al: 5.5 to 6.5 wt%, Ti: 0.5 to 1.0 wt%, B: A method for producing a Ni-based superalloy comprising 0.005 to 0.015% by weight, Zr: 0.05 to 0.15% by weight, Ca, Y or a combination of these elements: 0.01 to 1.0% by weight, and the balance consisting of Ni and an unavoidable impurity. A method for producing a Ni-based superalloy comprising dissolving Ni in any one of induction heating, arc melting, plasma heating, and electron beam melting, and uniformly dispersing each additional element.