JPS5974266A - High hardness fe-ni-cr alloy for valve and valve seat for engine - Google Patents

Abstract

PURPOSE:To improve the hardness at high temp. as well as the resistance to thermal shock and corrosion due to lead oxide by adding prescribed percentages of Fe, C, Cr, Ni, Co, W, etc. CONSTITUTION:The titled alloy consists of, by weight, 1.9-3.4% C, 25-55% Ni, 1-8% Co, 0.1-15% W, 0.1-9% Mo, 0.01-4.5% Ti, 0.01-4.5% Al and the balance Fe. 0.1-3% Si may be contained in the alloy. The alloy has superior hardness at high temp. as well as superior resistance to thermal shock and corrosion due to lead oxide.

Description

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

Fe-Ni has high hardness and lead oxide corrosion resistance, and is suitable for use in the production of engine pulp and valve seats for internal combustion engines that require these properties, as well as for casting and overlay welding. -It relates to Cr-based alloys.

Conventionally, when manufacturing engine pulp and valve seats for internal combustion engines, American Welding Society standard 5.13 RCoCr-A (C: 0.9 to 1.4) was used for overlay welding.
%, Si2: 2.0% or less, Mn: 1.0% or less,
W: 3, O~6.0%, Cr: 26~32%, N
i: 3.0% or less, Fe: 3.0% or less, Mo: 1.0
% or less, Co and unavoidable impurities: remainder), and 5.
13 RCoCr-B (C: 1, 2-1.7%, Si:
2.0% or less, Mn: 1.0% or less.

W near, O ~ 9.5%, Cr: 26 ~ 32%, Ni: 3
．． 0% or less, Fe: 3.0% or less, Mo: 1.0% or less, Co and unavoidable impurities: remaining 1 or more (by weight).

CO-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 pulp and valve seats of internal combustion engines are required to have even better properties. In particular, when high hardness is required, high-temperature hardness with a Vickers hardness of 320 or higher at a temperature of 800°C is required in both build-up welding conditions, and water cooling is performed after holding the temperature at near 00°C for 15 minutes. Thermal shock resistance of 5 or more operations before cracking occurs in the overlay weld when repeated, and weight loss after being immersed in a molten oxidation vessel heated to 920°C for 1 hour. o
, 09 g/crl/hr or less lead oxide corrosion resistance is now required. In addition,
It goes without saying that engine pulp castings and valve seat castings for internal combustion engines manufactured by casting are similarly required to have these characteristics.

However, the above-mentioned conventional Co-based alloys not only do not satisfy the upper limit requirements in terms of high-temperature hardness, but also do not have properties that satisfy these requirements in terms of thermal shock resistance and lead oxide corrosion resistance. In particular, for the production of engine pulp and valve seats for high-performance engines that require high hardness.
At present, when the conventional C○-based alloy is used for overlay welding and furthermore for casting, 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 pulp 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: over 1.9 ~ 3.4%, Cr: 28 ~ 3
7%, Ni: 25-55%, Co: 1-8%, W
: 0.1-15.0 To, M.

: 0.1 to 8.0%, Ti 20, 01 to 4.5%, /V:
0.01 to 4.5, and further contains Si as necessary
: 0.1-3.0%, Mn: 0.1-2.0%,
Nb: 0.01 to 1.5, and B: O, OO1
A Fe-Ni-Cr alloy containing one or more of the following 1.5% and having a composition (the above weight %) consisting of Fe and unavoidable impurities is a Vickers alloy at a temperature of 2800°C. It has an extremely high high-temperature hardness of 2330 or more, and in a thermal shock test in which one cycle is heating to 700℃ for 15 minutes and then water cooling, the number of cycles until cracking is 7 or more. It exhibits excellent thermal shock resistance, and in a lead oxide corrosion test by immersing it in a molten oxidation vessel heated to 2,920°C for 1 hour, the weight loss was 0.03
It exhibits excellent lead oxide corrosion resistance of less than s g 1 crli hr, and can be used for overlay welding and casting. They found that when used in the production of sheets, it exhibits excellent performance over an extremely long period of time.

This invention was made based on the above knowledge, and the reason why the component composition was limited as described above will be explained below.

(a) C The C component has the effect of combining with Cr, W, Mo, Ti, Nb, etc. to form carbides and significantly improving the hardness at room temperature and high temperature.
．． If the content is less than 9%, particularly high high-temperature hardness cannot be ensured, while if the content exceeds 3.4%, the thermal shock resistance will rapidly deteriorate, so the content should be reduced to 1. It has been set at over 9% to 3.4%.

(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 28%, the desired effect cannot be obtained, while if the content exceeds 37%, thermal shock resistance tends to decrease. Therefore, its content was determined to be 28-37%.

(c) Ni The Ni component not only stabilizes the austenitic base and improves thermal shock resistance and toughness, but also combines with AA and Ti to form an intermetallic compound: Ni, (AIL + Ti), which increases hardness at high temperatures. It has the effect of improving high-temperature wear resistance) and high-temperature strength, and also improves lead oxide corrosion resistance when coexisting with Cr, but if its content is less than 25%, the desired effect cannot be obtained, On the other hand, even if the content exceeds 55%, no further improvement effect can be obtained, so in consideration of economic efficiency, the content was set at 25 to 55%.

(d)　C.

The COC 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%, it will not have the desired effect. 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%.

(e+1 W The W component has the effect of refining carbides, forming carbides themselves, and solid-dissolving them in the matrix to strengthen it, thereby improving the high-temperature hardness and high-temperature strength of the alloy. If the content of copper is less than 0.1%, the desired effect cannot be obtained in the above action, while if the content exceeds 15.0%, overlay weldability and machinability will deteriorate. Its content was determined to be 0.1 to 150%.

(f) In coexistence with W, the Mo MOC component forms a solid solution in the base material,
It has the effect of strengthening this and forming carbides to improve the alloy's high-temperature hardness, high-temperature wear resistance) and high-temperature strength, but if its content is less than 0.1%, the desired effect cannot be obtained. On the other hand, if the content exceeds 9.0%, the thermal shock resistance and toughness deteriorate as in the case of the W component, so the content was determined to be 0.1 to 90%.

(g) Ti The T1 component not only suppresses the growth of crystal grains in the substrate, but also refines the crystal grains and combines with MC type carbides and nitrides, as well as N1 and M to form Ni3 (
AJ Ti) has the effect of forming an intermetallic compound to improve 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 will not be achieved. On the other hand, if the content exceeds 4.5%, the amount of carbides becomes too large, leading to deterioration of thermal shock resistance and toughness, and a tendency to deteriorate lead oxide corrosion resistance. Therefore, the content was determined to be 0.001 to 4.5%.

(h) AI An component contains Cr to improve lead oxide corrosion resistance,
And as mentioned above, it combines with Ni and T1 to form Ni3(A
1. In addition to forming intermetallic compounds of 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 amount 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, but also the weldability will decrease. Since the toughness also decreases and the content becomes impractical, the content was set at 0.01 to 4.5%.

(i) The 5i Si 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 the content is less than 1%, the desired improvement effect on the above action cannot be obtained, and on the other hand, if the content exceeds 3.0%, no further improvement effect can be expected. Established.

In addition, since the Si component has a deoxidizing effect, it is often used as a deoxidizing agent. The total content, including the unavoidable impurity content, may 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; The content was set at 0.1 to 2.0 because no further improvement effect would be obtained even if the content exceeded.

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 Si component, it must be contained as an unavoidable impurity in a range of less than 0.1%. However, the content as an alloy component includes this inevitable impurity content.

The total amount may be 0.1% or more.

(K) Nb The Nb component has the effect of suppressing the growth of crystal grains in the base material in particular, 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 when high-temperature hardness is particularly required, but if the content is less than 0.01%, the desired effect of improving the above action cannot be obtained, while if it exceeds 1.5%. If it is contained, the lead oxide corrosion resistance and thermal shock resistance will deteriorate, and the toughness will also decrease, so the content was set at 0.001 to 1.5%.

(tI B components include high temperature hardness and high temperature wear resistance), thermal shock resistance,
Since it has the effect of further improving lead oxide corrosion resistance and high-temperature strength, it may be included as necessary, but if the content is 0. If the content is less than 1.001%, the desired effect of improving the above action cannot be obtained, while if the content exceeds 1.5%, the thermal shock resistance will decrease, and the castability and weldability will also deteriorate. Therefore, the content is 0.00
It was set at 1 to 1.5%.

Next, the Fe--Ni--Cr alloy of the present invention will be specifically explained using examples and comparing with comparative examples.

Examples Alloys 1 to 40 of the present invention having the compositions shown in Table 1 were prepared by a conventional melting method. Comparative alloys 1 to 12. A conventional alloy 1.2 having a composition corresponding to the above-mentioned conventional CO-based alloy was melted and then continuously cast under normal conditions to form a welded rod with a diameter of 4.8 mlφ. . Note that Comparative Alloys 1-12 all have compositions in which the content of one of the constituent components (those marked with * in Table 1) is outside the scope of the present invention.

Next, the resulting alloys of the present invention 1-40° and comparative alloys 1-12. And using a welding rod of conventional alloy 1.2, diameter: 120 mm φ x thickness 22 mm using a TIG automatic welding machine.
Stainless steel (SUS 316) with dimensions of 0mx
Two layers of annular bead welding was performed on the surface of the base metal, with an outer diameter of 100 mm, a width of 20 mm, and a thickness of 5 mm.

Subsequently, the Rockwell hardness at room temperature (C scale) and Vickers hardness at a temperature of 800°C were measured for the annular bead formed on the base metal, and the alloy from which the annular bead was formed was measured. A thermal shock resistance test was conducted in which the operation of heating to near 00°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, a piece of stainless steel (sus
316) - A two-layer build-up welding with a thickness of F5 dragon was performed on the blade end surface, and a test piece with dimensions of diameter: 12, ..., φ x thickness: 12 mm was made from the build-up part of this steel piece. Molten lead oxide was cut out and heated to a temperature of 920°C using this test piece: 4
A lead oxide corrosion resistance test was conducted by immersing the material in Oy for 1 hour, and the weight loss of the overlay material after the test was measured. These measurement results are also shown in Table 1.

From the results shown in Table 1, it is clear that Alloys 1 to 40 of the present invention have better high-temperature hardness, thermal shock resistance, and lead oxide corrosion resistance than conventional Alloy 1.2. It is. On the other hand, as seen in Comparative N1-base alloys 1 to 12, when the content of any one of the constituent components falls outside the range of the present invention, at least one of the above properties is lower than that of the present invention alloy. It is clear that one of the characteristics will be inferior.

In addition, in the above example, a case was described in which the Fe-Ni-Cr alloy of the present invention was used for overlay welding, but
It goes without saying that even when used for casting, it exhibits excellent properties similar to those for overlay welding.

As mentioned above, the Fe-Ni-Cr alloy of the present invention.

Excellent high-temperature hardness and thermal shock resistance that fully satisfy the above-mentioned strict conditions required for engine pulp and Nokrug sheet for 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

Claims (1)

[Claims] (1) C: more than 1.9% to 3.4%, Cr: 28 to 37%
. Ni: 25-55%, Co: 1-8%, W: 0.1-
15.0%, Mo: 0.1-9.0%, Ti:
0.01-4. r%, A1: 0.01-4.5%
High hardness Fe-Ni- for use in engine pulp and valve seats of internal combustion engines, characterized by having a composition (by weight %) in which the remainder consists of Fe and unavoidable impurities.
Cr-based alloy. (21C: more than 1.9% to 3.4%, Cr: 28-3
7%. Ni: 25-55%, Co: 1-8%, W: 0.1-1
5.0%, Mo: O, 1-9.0%, Ti:
0.01-4.5%, Ag: 0.01-4.5
%, and Si: O, 1 to 3.0%, and the remainder is Fe and unavoidable impurities (weight %) for engine pulp and valve seats of internal combustion engines. High hardness F6-Ni-Cr alloy. (3) C: more than 1.9% to 3.4%, Cr: 28 to 3
7%. Ni: 25-55%, Co: 1-8%, W: O, 1-1
5.0%, Mo: 0.1-9.0%, Ti:
0.01-4.5%, At: 0.01-4.5%
, and Mn: 0.1 to 2.0, with the remainder being Fe.
A high hardness Fe-Ni-Cr alloy for use in engine pulp and valve seats of internal combustion engines, characterized by having a composition (the above weight %) consisting of unavoidable impurities. (4) C: more than 1.9% to 3.4%, Cr: 2B
~37%. Ni: 25-55%, Co: 1-8%, W:
0.1-15.0 ratio, Mo: 0.1-9.0 ratio, Ti:
0.01-4.5%, Ag: 0.01-4.5%
, Si: 0.1 to 3.0%, and Mn: 0.
High hardness F for engine pulp and valve seats of internal combustion engines, characterized by having a composition (by weight %) containing 1 to 2.0% and the remainder consisting of Fe and unavoidable impurities.
e-Ni-Cr alloy. (5) C: more than 1.9% to 3.4%, Cr: 28 to
37%. Ni: 25-55%, Co: 1-8%, W
: O51~15.0%, Mo: 0.1~
9.0%, Ti: 0.01-4.5%, Al:
Contains 0.01-4.5%, further Nb: 0
．． A high hardness Fe-Ni-Cr alloy for use in engine pulp and valve seats of internal combustion engines, characterized by having a composition (by weight %) containing 01 to 1.5% Fe and the remainder consisting of Fe and unavoidable impurities. . (6) C: more than 1.9% to 3.4%, Cr: 2B to 37%
. Ni: 25-55%, co: 1-8%, W: 0.1-1
5.0%, Mo: 0.1-9.0%, Ti:
0.01-4.5%, Al: 0.01-4.5%
, and Si: 0.1 to 3.0%, further containing Nb: o, o 1 to 1.5%, and the balance is composed of Fe and inevitable impurities (C or more weight %). Features: Fe-Ni-Cr alloy for engine pulp and valve seats of internal combustion engines. (7) C: more than 1.9% to 3.4%, Cr: 2 BN
27%. Ni: 25-55%, co=1-8%, W: 0.1-
15.0%, Mo:O, 1-9.0%, Ti: 0
．． O1, ~4.5%, All: 0.01~4.5
%, and Mn: 0.1 to 2.0, and further contains Nb: o, ol to 1.5. Composition with the remainder consisting of Fe and unavoidable impurities (more than % by weight)
A high WJ degree Fe-Ni-Cr alloy for use in engine pulp and valve seats of internal combustion engines, characterized by having the following characteristics: (8) C: more than 1.9% to 3.4%, Cr: 28 to 37%
. Ni: 25-55% lCo: 1-8%, W: 0.1-
15.0%, Mo: O, 1-9.0%, T1:0
．． 01-4.5%, AA: 0.01-4.5%
, Si: 0.1-3.0%, and Mn: 0.1
~2.0% and further Nb:O, O1~1.5%
High hardness Fe-Ni for engine pulp and valve seats of internal combustion engines, characterized by having a composition (weight %) of Fe and unavoidable impurities.
-Cr-based alloy. (9) C: more than 1.9% to 3.4%, Cr: 28-3
7%. Ni: 25-55% lCo: 1-8%, W: 0.1-
15.0%, Mo: 0.1-9.0%, Ti: 0001
~4.5%, A1:o, o1~4.5%, further contains B: 0.001~1.5%, and the remainder is Fe and unavoidable impurities. A high hardness Fe--Ni--Cr alloy for use in engine pulp and valve seats of internal combustion engines, having the following characteristics: (10) C: more than 1.9% to 3.4%, Cr: 28
~37%. Ni: 25-55%, Co: 1-8%, W: 0.1-1
5.0%, Mo: 0.1-9.0%, Ti: 0
．． 01 to 4.5%, AA: 0.01 to 4.5%, and Si: 0.1 to 3.0%, and further B: O, O
High hardness Fe-Ni-Cr system for engine pulp and valve seats of internal combustion engines, characterized by containing Ol -1.5 and having a composition (weight %) consisting of Fe and unavoidable impurities. alloy. (11) C: 1. More than 9%~3.
4% r cr 2 2 B ~ 3
7%. Ni: 25-55%, Co: 1-8%, W: 0.1-1
5.0%, Mo: 0.1~9゜0%, Ti: 0
．． 01-4.5%, A9: 0.01-4.5%,
and Mn:Q, containing a ratio of 1 to 2.0, and further B:O
A high hardness Fs-Ni-Cr system for engine pulp and valve seats of internal combustion engines, characterized by having a composition (weight %) containing 1 to 1.5 parts of OO, and the remainder consisting of Fe and unavoidable impurities. alloy. (12) C: more than 1.9% to 3.4%, Cr: 2
8-37%. Ni: 25-55%, Co: 1-8%, W
:0.1~15.0%, Mo:0.1~9.0
%, Ti: 0.0 1-4.5 section, AA: 0
．． 01-4.5%, Si: 0.1-3.0%, and M
Contains n: 0.1 to 2.0%, and further B: o, o
High hardness Fe- for engine pulp and valve seats of internal combustion engines, characterized by having a composition (by weight) containing 1.5% of o:L and the remainder consisting of Fe and unavoidable impurities. Ni-Cr alloy. (13) C: more than 1.9% to 3.4%, Cr: 28 to
37%. Ni: 25 to 55%, co =
1-8%, W20, 1-15.0%
, Mo: 0.1-9.0%, 'ri: 0.0
1 to 4.5, AA: 0.01 to 4.5%, further Nb: 0.01 to 1.5% and B: O, OO1 to
A high-hardness Fe- pulp for internal combustion engines and valve seats, characterized by having a composition (by weight %) containing 1.5% Fe and the remainder consisting of Fe and unavoidable impurities.
Ni-Cr alloy. (14) C': more than 1.9% to 3.4%, C
r: 28-37%. Ni 2 25 ~ 55 Jiwarm, Coal ~
8%, W: 0.1-15.0%, Mo
: 0.1-9.0%, Ti: 0.01
~4.5 ratio, M: 0.01~4.5%, and Si: 0
．． 1 to 3.0, and further contains Nb: 0.01 to 1.
5% and B: 0.001 to 1.5%, and the remainder is Fe and unavoidable impurities. High hardness Fe-Ni-Cr alloy for use. (15) C: more than 1.9% to 3.4%, Cr: 2
8-37%. Ni: 25-55%, Co: 1-8%, W: 0.
1-15.0%, Mo: 0.1-9.0%, Ti
: 0.01-4.5%, Ae: 0. '01~4
．． 5%, and Mn: 0.1 to 2.0%, further Nb: 0.01 to 1, 5%, and B: O, OO1 to
High hardness Fe- for engine pulp and valve seats of internal combustion engines, characterized by having a composition (by weight %) containing 1.5% and the remainder consisting of Fe and unavoidable impurities.
Ni-Cr alloy. (16) C: more than 1.9% to 3.4%, Cr: 28 to
37%. Ni: 25-55%, Co: 1-8%, W: 01-15
．． 0%, Mo: 0.1-9.0%, Ti:
0. Ol to 4.5 section, Au: 0.01 to 4.5 section, S
i: 0.1-3.0%, and Mn: 0.1-2.0
%, and further contains Nb:O, O1-1.5% and B
:High hardness Fe-Ni for engine pulp and valve seats of internal combustion engines, characterized by containing 1 to 1.5% of O, OO, with the remainder consisting of Fe and unavoidable impurities (weight %) -Cr-based alloy.