JPS596348A - Ni base alloy for engine valve and valve seat thereof - Google Patents

Abstract

PURPOSE:To provide a Ni base alloy excellent in high temp. hardness, heat shock resistance and lead oxide corrosion resistance, obtained by containing C, Cr, Fe, W, Co, Mo, Ti and Al in Ni in a specific ratio. CONSTITUTION:A Ni base alloy having a composition containing, on the basis of a wt., 0.55-2% C, 10- less than 28% Cr, 1-30% Fe, 0.1-17.0% W, 1-8% Co, 0.1-8.0% Mo, 0.01-4.5% Ti and 0.01-4.5% Al and comprising the remainder Ni and inevitable impurities is prepared. According to necessity, 0.1-3.0% Si or 0.1-2.0% Mn can be contained and, further, if necessary, one or both of 0.01- 1.5% Nb and 0.01-1.5% B can be contained. When this alloy is used in welding or in preparing a cast article, excellent properties are developed over a long period.

Description

[Detailed description of the invention] This invention has excellent high temperature hardness and thermal shock resistance.

N1 has lead oxide corrosion resistance and is suitable for use in castings or overlay welding in the manufacture of engine valves and valve seats for internal combustion engines that require particularly good hole properties. It concerns base alloys.

Conventionally, when manufacturing engine valves and valve seats for internal combustion engines, American Welding Society standard 5.13RCoCr-A (C: 0.9 to 1.4) was used for overlay welding.
%, Si: 2.0% or less, Mn: 1.0% or less, W: 3
0 to 6.0%, Cr: 26 to 32%, Ni: 3. O% or less, Fe2: 3.0% or less, Mo: 1.0% or less, Co
and unavoidable impurities; remainder) and 5.13 RCoC
r-B (C: 1.2~1.7%, Si: 2.0% or less, Mn: 1.0% or less, W: '7.0~9.5
%, Cr: 26-32%, Ni: 3.0% or less,
Fe2: 3.0% or less, Mo: 1.0% or less.

CO and unavoidable impurities: remaining 1% or more by weight), etc.
O-based alloys (hereinafter referred to as conventional Co-based alloys) have been widely used.

On the other hand, as the performance of internal combustion engines has improved in recent years, the engine valves and valve seats of internal combustion engines are also required to have better characteristics. - In general, the Vickers hardness at a temperature of 2800°C is 285 in the build-up welding state.
The above high-temperature hardness, and the thermal shock resistance of 7 or more operations before cracking occurs in the overlay weld when the water cooling operation is repeatedly performed after holding the temperature at near 00 ° C. for 15 minutes, Furthermore, the weight loss after being immersed in a molten oxidation vessel heated to 915℃ for 1 hour was 0.09! 7/ffl
It is now required to have lead oxide corrosion resistance of /hr or less. It goes without saying that engine valve castings and valve seat castings for internal combustion engines manufactured by casting are similarly required to have these characteristics.

However, although the above-mentioned conventional CO-based alloys satisfy the above requirements in terms of high-temperature hardness, they do not have properties that satisfy these requirements in terms of thermal shock resistance and lead oxide corrosion resistance, and therefore have high performance. At present, when the conventional Co-based alloy is used for overlay welding or for casting in the production of engine valves and valve seats for engines, it does not exhibit a sufficiently satisfactory service life.

Therefore, from the above-mentioned viewpoint, the present inventors have developed a material that has the high-temperature hardness, thermal shock resistance, and lead oxide corrosion resistance required for engine valves and valve seats for internal combustion engines, particularly high-performance engines. As a result of research to develop a material that can be used for overlay welding and casting, we found that C: 0.55 to 2.0%, Cr: 10 to less than 28%, Fe2 to 30%. %, W: 0.1-17.0, Co
: 1-8% 1MO: 0, 1-8.0%, Ti: 0.01
~4.5%, AU: 0.01~4.5%, Si: 0.1~3.0 or Mn: 0.1~4.5% as necessary.
2.0, and further contains Nb:o, o1 as necessary.
~1.5 Chi and B: 0. 1 out of OO1-1.5%
An N1-based alloy containing one or two species and the remainder consisting of one odor and unavoidable impurities (in weight percent) has a temperature of:
It has extremely high temperature hardness with a Vickers hardness of 2310 or more at 800℃, and in a thermal shock test in which one cycle is heating to near 00℃ for 15 minutes and then water cooling, the number of cycles until cracking is It showed excellent thermal shock resistance over 13 times, and in a lead oxide corrosion test by immersing it in a molten oxidation vessel heated to 915°C for 1 hour, the weight loss was 0.034 g/c-I! It exhibits excellent lead oxide corrosion resistance of less than /hr and can be used for overlay welding and casting.Therefore, the N1-based alloy is used for the production of engine pulp and valve seats for high-performance engines. They obtained the knowledge that they can exhibit excellent performance over an extremely long period of time when

This invention has been made based on the above knowledge, and the reason why the component composition is limited to the above general composition will be explained below.

(a) C The C component includes Cr, W, Mo, Ti, and N
It combines with B and the like to form carbides and has the effect of improving hardness at room temperature and high temperature. However, if its content is less than 0.55%, the desired high hardness cannot be achieved; on the other hand, 2.
If the content exceeds 0%, the thermal shock resistance will deteriorate, so the content was set at 0.55 to 20%.

(b) Cr A part of the Cr component dissolves in the base material, and the remaining part forms a carbide, which particularly improves high-temperature hardness and high-temperature wear resistance, as well as lead oxidation resistance. It has the effect of improving corrosion resistance, but if the content is less than 10%, the desired effect cannot be obtained, while if the content is 28% or more, the thermal shock resistance tends to decrease. Its content was determined to be less than 10% to 28%.

(c) Fe The Fe component has the effect of further improving the thermal shock resistance of the alloy, but if its content is less than 1%, the desired thermal shock resistance cannot be secured, whereas if it exceeds 30%, When it is included, the high temperature hardness decreases, and the temperature: 8oo
Since it was not possible to ensure a Vickers hardness of 1285 or higher at °C, the content was determined to be 3 to 30%.

(a) W The W component has the effect of refining carbides, forming carbides themselves, and solid-dissolving them in the matrix to strengthen them, thereby improving the high-temperature hardness and high-temperature strength of the alloy. However, if the content is less than 17.0%, the desired effect cannot be obtained, while if the content exceeds 17.0%, overlay weldability and machinability will deteriorate. The content was determined to be 0 to 17.0.

(e) C.

The co-acid component dissolves in the base material and has the effect of further improving thermal shock resistance and improving high-temperature hardness and high-temperature abrasion resistance, but if its content is less than 1%, the desired effect will not be achieved. On the other hand, even if the content exceeds 8%, no further improvement effect can be obtained.Considering economic efficiency, the content was set at 1 to 8%.

(f) M.

In the coexistence with W, the MO acid component becomes solid solution in the base material,
It has the effect of strengthening this and forming carbides to improve the high-temperature hardness, high-temperature wear resistance) and high-temperature strength of the alloy, but if its content is less than 0.1%, the desired effect cannot be achieved. On the other hand, if the content exceeds 8.0,
As in the case of the W component, the thermal shock resistance and toughness deteriorate, so the content was determined to be 0.1 to 8.0%.

(g) Ti The Ti component not only suppresses the growth of crystal grains in the substrate, but also refines the crystal grains and forms Ni3 by combining with MC-type carbides and nitrides, as well as N1 and AU.
(AL Ti ) forms an intermetallic compound, which has the effect of improving high-temperature hardness and thermal shock resistance, as well as high-temperature strength and toughness, but if its content is less than 0.01%, the desired effect is not achieved. On the other hand, if the content exceeds 4.5%, the amount of carbides becomes too large and thermal shock resistance and toughness deteriorate, and lead oxide corrosion resistance also tends to deteriorate. The content was determined to be 0.001 to 4.5%.

(h) hp.

The Al component, together with Cr, improves lead oxide corrosion resistance.
And as mentioned above, it combines with Ni and Ti to form Ni3(A
In addition to forming intermetallic compounds (Q, Ti), it also forms nitrides to improve hardness at room and high temperatures, further increasing wear resistance, and further improving thermal shock resistance and high temperature strength. If the content is less than 0.01%, the desired effect cannot be obtained, while if the content exceeds 4.5%, not only will the fluidity and castability of the molten metal decrease, Since the weldability and toughness also decrease and it becomes impractical, the content should be set at 0.01 to 4.5.
%.

(i) 5i The S1 component has the effect of improving castability, overlay weldability, and melt flowability, so it is included as necessary when these properties are particularly required. The amount is 0.
If it is less than 1%, the desired effect of improving the above action cannot be obtained;
On the other hand, even if the content exceeds 3.0%, no further improvement effect can be expected, so the content should be increased from 0.1 to 340%.
%.

In addition, since the S1 component has a deoxidizing effect, it is often used as a deoxidizing agent, and in this case it is contained as an unavoidable impurity in a range of less than 0.1%, but as an alloy component. The total content, including the content of these unavoidable impurities, should be 0.1% or more.

(j) Mn Since the Mn component has the effect of improving overlay weldability,
In particular, it is contained as necessary when overlay weldability is required, but if the content is less than 0.1%, the desired improvement effect on overlay weldability cannot be obtained; Even if the content exceeds 0.1 to 2.0, the content is set at 0.1 to 2.0.

In addition, since the Mn component has a deoxidizing and desulfurizing effect, it is often used as a deoxidizing and desulfurizing agent, and in this case, like the S1 component, it must be included as an unavoidable impurity in a range of less than 01%. The total content as an alloy component, including the content of unavoidable impurities, may be 0.14 or more.

(k) Nb The Nb component has the effect of suppressing the growth of crystal grains in the base material and forming MC-type carbides and nitrides to further improve high-temperature hardness and high-temperature wear resistance) and high-temperature strength. Therefore, it is included as necessary especially when high temperature hardness is required, but if the content is less than 0.01%, the desired effect cannot be obtained; If the content exceeds 0.05%, the lead oxide corrosion resistance and thermal shock resistance will deteriorate, and the toughness will also be reduced. Therefore, the content was set at 0.01 to 1.5.

(7) B-day components include high-temperature hardness, high-temperature wear resistance), thermal shock resistance,
It has the effect of further improving lead oxide corrosion resistance and high-temperature strength, so it is included as necessary, but if the content is less than 0.001%, the desired effect of improving the above effects cannot be obtained; If the content exceeds 0.5%, the thermal shock resistance will decrease, and the castability and weldability will also deteriorate.
1.5 section.

Next, the N1-based alloy of the present invention will be specifically explained using examples and comparing with comparative examples.

Examples N1-based alloys 1 to 36 of the present invention having the compositions shown in Table 1 were prepared by a conventional melting method. Comparative Ni-based alloys 1 to 13. Conventional alloy 1.2, which has a composition equivalent to the conventional Co-based alloy mentioned above, is melted and then continuously cast under normal conditions to form a welded rod with a diameter of 48 mm. did.

Comparative Ni-based alloys 1 to 13 all have compositions in which the content of one of the constituent components (those marked with * in Table 1) is outside the scope of this invention. .

Next, the resulting N1-based alloys of the present invention 1 to 36.
Comparative N1-base alloy 1-13. And using a conventional alloy 1°2 welding iron with a TIG automatic welding machine, diameter: 120.
Stainless steel (S) with dimensions of φ x thickness: 20 mrn
Two layers of an annular bead having an outer diameter of 100 il, a width of 20 m, and a thickness of 5 mm were welded onto the surface of a base metal manufactured by US 316).

Subsequently, the Rockwell hardness at room temperature (C scale) and the Vickers hardness at a temperature of 800°C were measured for the annular bead formed on the mount, and the alloy on which the annular bead was formed was measured. On the other hand, a thermal shock resistance test was conducted in which the operation of heating to 700° C., holding for 15 minutes, and then cooling with water was repeated as one cycle, and the number of cycles until cracking occurred in the annular bead was measured. Furthermore, diameter: 15mrlLφ
x Length:: Stainless steel piece with dimensions too long (S
Two-layer overlay welding with a thickness of 5 mm was performed on one end face of the steel piece, and a diameter of 12 m, φ x
A test piece with a thickness of 12 mm was cut out, and using this test piece, molten lead oxide was heated to a flow rate of 915°C:
A lead oxide corrosion resistance test was conducted by immersing it in 40g for 1 hour.
The weight loss of the built-up part after the test was measured. These measurement results are also shown in Table 1.

From the results shown in Table 1, the N1-based alloys 1 to 36 of the present invention
It is clear that all of these alloys have superior hardness, thermal shock resistance, and lead oxide corrosion resistance compared to conventional alloy 1.2. On the other hand, comparative Ni-based alloys 1~
As seen in No. 13, if the content of any one of the constituent components falls outside the scope of the present invention, at least one of the above properties is inferior to the N1-based alloy of the present invention. It is clear that

In addition, in the above example, a case was described in which the N1-based alloy of the present invention was used for overlay welding, but it can also be used for castings and exhibits excellent properties similar to those for overlay welding. Of course.

As mentioned above, the Ni-based alloy of the present invention has excellent high-temperature hardness, thermal shock resistance, and satisfies the above-mentioned strict conditions required for engine pulp and valve seats of high-performance engines. It also has lead oxide corrosion resistance, so when it is used for overlay welding and casting in the manufacture of these parts, the resulting parts exhibit excellent performance over an extremely long period of time.

Applicant: Mitsubishi Metals Corporation Agent Tomi 1) Kazuo 22-

Claims (1)

[Claims] (IJC: 0.55-2.0%, Cr: l
O~less than 28%, Fe: 1~30%, W:
0.1-17.0%, Co: 1-8%, Mo: 0
．． 1 to 8, Oqb, Ti: 0.01 to 4.5,
A Ni-based alloy for engine valves and valve seats of internal combustion engines, which contains AN: 0.01 to 4.5%, with the balance consisting of N1 and unavoidable impurities (weight percent). (2) C: 0.55-2.0%, Cr: l
O~less than 28%, Fe: 1~30%, W: 0.
1-1 'i', o%, Co: 1-8%, Mo:
0.1-8.0%, Ti: 0.01-4.5%
, AA: 0.01-4.5%, and Si:
Ni base for internal combustion engine engines/groups and valve seats, characterized by containing 0.1 to 3.0%, with the remainder consisting of N1 and unavoidable impurities (weight %) alloy. (3) C: 0.55-2.0%, Cr: 10
~Less than 28%, Fe: 1-30%, W: 0.1
-17.0%, Co: 1-8%, Mo:
O, 1-8.0%, Ti: 0.01-4.5%,
AA: 0.01-4.5%, and Mn: 0.
An N1-based alloy for use in engine valves and valve seats of internal combustion engines, characterized in that it contains 1 to 2.0% of N1 and the remainder consists of N1 and unavoidable impurities (weight percent). (4) C: CI 55~2-04 TCr:
10 to less than 28%, Fe: 1 to 30%, W: 0
．． 1-17.0%, Co: 1-8%, Mo: O
,1~B, 0%, Ti: 0.01~4.5%,
AQ: Contains 0.01 to 4.5%, further contains 0.01 to 1.5% of Nb, and the remainder is Ni and unavoidable impurities (weight%). N for engine valves and valve seats of internal combustion engines
1 base alloy. (5) C: 0. 5 5 ~ 2.0%
, Cr 2 O ~ less than 28%, Fe
: 1~30%, W: 0.1~1 'i', 0%,
Co: 1-8%, Mo: 0.1-8.0
%, Ti: 0.0 1-4.5%, A
e: 0.01~4.5%, and Si: 0.1~
An engine valve for an internal combustion engine characterized by containing 3.0% of Nb, further containing 0.01 to 15% of Nb, and the remainder consisting of Ni and unavoidable impurities (weight %). Ni-based alloy for valve seats. (6) C20,55~2.0%, Cr:
10 to 2 E (less than %, Fe: 1 to 30%
, W: 0.1-17.0 qb, C. :1 to 8%, Mo: 0.1 to 8.0%, Ti: 0.
01-4.5%, AQ: 0.01-4.5%,
and Mn: 0.1 to 2.0%, and further contains N
N1-based alloy for engine valves and valve seats of internal combustion engines, characterized in that it contains 0.01 to 1.5% of b: and the remainder consists of N1 and unavoidable impurities (hereinafter referred to as "double maximum"). . ('7) C: 0.55-2.0%, Cr: 1
0 to less than 28%, Fe: 1 to 30%, W:
0.1~1 'i', o%, Co: ]-~8%, Mo
: 0.1-8.0%, Ti: 0.01-4.5%, AQ: o, o1-4.5%, further B: 0,
1. An N1-based alloy for use in engine valves and valve seats of internal combustion engines, characterized in that it contains 0.001 to 15%, with the remainder consisting of N1 and unavoidable impurities (weight percent). (8) C: 0.55 to 2.0%,
Cr: less than 10 to 28%,
Fe: 1-30%, W: 0.1-17.0%, C
o: 1-8%, Mo: 0.1-8.0%, Ti:
0.01-4.5%, AM: 0.01-4.5
%, and Si: 0.1-3.0%, further contains BO, OO 1-1.5%, and the remainder is N1 and unavoidable impurities (weight %). Features: N1-based alloy for engine valves and valve seats of internal combustion engines. (9) C: 0.55-2.0%, Cr: 1
0 to less than 284, Fe: 1 to 30%,
W: 0.1-17.0%,
Co: 1-8%, Mo: 0.1-8.0%, Ti: 0.
01-45%t AQ: 0.01-4.5%, and Mn: 0.1-2.0%, and further contains B:O,
N1 for engine valves and valve seats of internal combustion engines, characterized by having a composition (weight %) containing 1 to 1.5% OO, with the remainder consisting of Ni and unavoidable impurities
Base alloy. (10) C: 0.55-2.0%, Cr:'10
~Less than 28%, Fe: 1~30%, W: 0.1~
1"1.0%, Co: 1~8 Chi, Mo: 0.1~
8.0%, Tf: 0.0 1-4.5%,
AQ:9. o1 to 4.5%, and further contains Nb: 0.
01 to 1.5 and B: 0.001 to 15%, with the remainder consisting of N1 and inevitable impurities (more than 1% by weight).
) for an engine valve and valve seat of an internal combustion engine. (11) C: 0.55-2.0%, Cr: 10-2
Less than 8%, Fe: 1 to 30%, W: 0.1 to l'i',
θ%, CO: 1-8% + Mo: 0.1-8.0
%+'ri: o, o 1-4.5 section, Alt: 0.
01 to 45% and Si: 0.1 to 3.0%, further Nb: 0.01 to 1.5% and B: O, O
An N1-based alloy for engine valves and valve seats of internal combustion engines, characterized by containing 1.5% of Ol-1, with the balance consisting of N1 and unavoidable impurities. (12) C: 0.55-2.0%, Cr:IO-2
Less than 8%, Fe: IN30%, W: 0.1
~1'7.0%, Co: 1-8%, Mo: 0.
1-8.0%, Ti: 0801-4.5%,
An: 0.01-4.5%, and Mn:
Contains Nb-0.1-2.0, and further contains Nb-0.01-1
．． 5% and B:0. An N1-based alloy for engine valves and valve seats of internal combustion engines, characterized in that it contains 1 to 1.5% of OO, with the remainder being N1 and unavoidable impurities (weight percent).