JPS58120756A - Ni alloy for valve and valve sheet of internal combustion engine - Google Patents

Abstract

PURPOSE:To enhance the hardness of the resulting titled alloy at high temp., the thermal impact resistance and the resistance to corrosion due to lead oxide by providing a specified composition consisting of C, Si, Mn, Cr, Fe, W, Mo, Ti, Al and the balance essentially Ni. CONSTITUTION:This Ni alloy for the valves and valve sheets of an internal combustion engine can be used as a material for build-up welding and casing and has a composition consisting of, by weight, 0.55-2.0% C, 0.1-3.0% Si, 0.1- 2.0% Mn, 10-<28% Cr, 3-30% Fe, 0.5-17.0% W, 0.5-8.0% Mo, 0.1-3.5% Ti, 0.1-3.5% Al and the balance Ni with inevitable impurities or further contg. 0.01-1.5% Nb and/or 0.001-1.5% B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has excellent high temperature hardness, thermal shock resistance, and lead oxide corrosion resistance, and is particularly suitable for manufacturing engine pulp and valve seats for internal combustion engines that require these properties. The present invention relates to a Ni-based alloy suitable for use in casting or overlay welding.

Conventionally, when manufacturing engine valves and valve seats for internal combustion engines, overlay welding was performed using American Welding Society standard 5.13RCOCr-A (C: O19-1.4%,
Si: 2.0% or less, Mn: l, Q% or less, W: 3.0
~6.0%, Cr: 26-32%, 'Ni: 3.
Less than 0%.

Fe: 3.0% or less, MO: 1.0% or less, Co and inevitable impurities: remainder I)), and 5.13 RCoCr
-B (C: 1.2 to 1.7%, Si: 2.0% or less, Mn: 1.0% or less.

w: 7.0-9.5%, cr: 26-32%
, Ni: 3.0 ratio or less, F'e: 3.0% or less,
Mo: 1. CO-based alloys (hereinafter referred to as conventional C
O-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 have also been required to have even better properties. , generally, both have a high temperature hardness with a Vickers hardness of 285 or higher at a temperature of 800°C in the overlay welding state, and a high temperature hardness of 700°C for 15 minutes and then repeated water cooling. Thermal shock resistance is 7 or more operations before cracking occurs in the welded part, and the weight loss after being immersed in a molten oxidation vessel heated to 915°C for 1 hour is 0.09 f/cr! /
It is now required to have lead oxide corrosion resistance of hr or less. 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, 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 pulp or concave 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: 0.55-2.0%, Si: 0.1-3.
, O%r Mn: o, 1~2.04Cr: l○~
Less than 28 inches, Fe: 3-30q6. W: 05-17.0
CH, MO: Q, 5-8.0%, Ti: 0.1-3.5 CH, Ai! , : 0.1-3.5%, and further contains Nb: 0.01-1.5% and B:O,O as necessary.
An N1-based alloy containing one or two of O1 to O15 and having a composition (or more by weight) consisting of N1 and unavoidable impurities has an extremely hard Vickers hardness of 1300 or more at a temperature of 8oO℃. It has high high-temperature hardness and has excellent thermal shock resistance, with the number of cycles required for cracking occurring over 14 times in a thermal shock test where one cycle is heating to near 00°C for 15 minutes and then cooling with water. Furthermore, in a lead oxide corrosion test of 1 hour immersion in molten lead oxide heated to a temperature of 915°C, the weight loss was 0.027 P/cIl/h.
It exhibits excellent lead oxide corrosion resistance of less than They found that in some cases, they exhibit 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 includes Cr, W, MO, Ti, and Nl.
), etc., to form a carbide, which has the effect of improving hardness at room temperature and high temperature. However, if the content is less than 0.155%, the desired high hardness cannot be achieved;
If the content exceeds K, the thermal shock resistance will deteriorate, so the content was set at 0.55 to 2.0%.

(b) si In order to ensure the desired deoxidizing effect, castability, overlay weldability, and melt flowability, a minimum content of 0.1% is required, but on the other hand, even if the content exceeds 3.0%. Since further improvement effects cannot be expected, the content should be reduced to 0.1-3.0%.
It was determined that

(c) Mn In addition to deoxidizing and desulfurizing, the Mn component has the effect of improving overlay weldability, but if its content is less than 1% O, the desired effect cannot be obtained; Even if the content exceeds 20%, no further improvement effect will be obtained due to the above-mentioned action, so the content was set at 01 to 2.0.

(d) Cr A part of the Cr component dissolves in the base material, and the remaining part forms carbide, which particularly improves high-temperature hardness and high-temperature wear resistance, as well as oxidation resistance. It has the effect of improving lead 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. , the content was determined to be less than 10 to 2 days.

(e) Fe The Fe component has the effect of further improving the thermal shock resistance of the alloy, but if its content is less than 3%, the desired thermal shock resistance cannot be secured; When it is contained, the high temperature hardness decreases, and the temperature: 800
Since it was not possible to ensure a Vickers hardness of 2285 or higher at °C, the content was determined to be 3 to 30%.

(f) 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 0.54%, the desired effect cannot be obtained, while if the content exceeds 17.0%, overlay weldability and machinability will deteriorate. The content was determined as 05 to near and 0.

(g) M.

In the Mo component, in coexistence with W, it forms a 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 the content is less than 0.5%, the desired effect cannot be obtained. On the other hand, if the content exceeds 8.0 cm, W
Since the thermal shock resistance and toughness deteriorate as in the case of the other components, the content was determined to be 0.5 to 8.0%.

(h) Ti Due to the Ti component, it not only suppresses the growth of crystal grains in the substrate, but also makes the crystal grains finer and combines with MC type carbides and nitrides, as well as Ni and M, resulting in Nis <
Mr'ri) 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 0.1%, the desired effect is not achieved. On the other hand, if the content exceeds 3.5 h, the amount of carbides becomes too large and thermal shock resistance and toughness deteriorate, and lead oxide corrosion resistance also tends to deteriorate. Therefore, the content was determined to be 0.1 to 3.5 yen.

(i) The A1 M component has N'3 (A
In addition to forming intermetallic compounds of g+ ``'), 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 0.1%, the desired effect cannot be obtained, while if the content exceeds 3.5%, the fluidity and castability of the molten metal will deteriorate. , the weldability and toughness also deteriorate, making it impractical, so the content was set at 0.01 to 3.5.

(j) 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 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, whereas if it exceeds 1.5%. If it is included, the lead oxide corrosion resistance and thermal shock resistance will deteriorate, and the toughness will also decrease, so the content was set at 0.1 to 1.5%.

(k) B The B component includes high temperature hardness, high temperature wear resistance), thermal shock resistance,
Since it has the effect of further improving lead oxide corrosion resistance and high temperature strength, 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, as well as the castability and weldability.
．． It was set at 5%.

Next, the Ni-based alloy of the present invention will be specifically explained by comparing examples and comparative examples.

Examples Alloys 1 to 26 based on the present invention having the compositions shown in Table 1 were prepared by a conventional melting method. Comparative Ni-based alloy 1
~14. A welded rod with a diameter of 4.8 gφ was made by melting conventional alloys 1 and 2 having compositions corresponding to the conventional Co-based alloys mentioned above, and then continuously casting them under normal conditions. Molded.

In addition, comparative Ni and base alloys 1 to 14 all have compositions in which the content of any one of the constituent components (marked with a ridge mark in Table 1) is outside the scope of this invention. be.

Next, the resulting E! ANi-based alloy 1-2
6. Comparative Ni-based alloys 1 to 14. and conventional alloy l.

Diameter:
120m, diameter: 10C1 on the surface of a stainless steel (SUS 316) base metal with dimensions of φ x thickness: 20mm.
A two-layer overlay welding was performed on an annular bead of ++m x width: ZO, x thickness: 5 tnw.

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, diameter: 15. , φ×length: 100. Stainless steel piece (SUS
316), a two-layer overlay welding with a thickness of 5n is performed on one end face of the steel piece, and the overlay part of this steel piece has a diameter of 12mm x thickness: 12
．． ．． A test piece with the dimensions of The weight loss of the wood was measured. These measurement results are also shown in Table 1.

From the results shown in Table 1, the N1-based alloys 1 to 26 of the present invention
It is clear that both of these alloys have superior high-temperature hardness, thermal shock resistance, and lead oxide corrosion resistance compared to conventional alloys 1 and 2. On the other hand, comparative Ni-based alloys 1~
As seen in No. 14, when 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 Ni-based alloy of the present invention. It is clear that

In addition, in the above example, a case was described in which the Ni-based alloy of the present invention was used for overlay welding, but even when it is used for casting, it 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 valves 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 Co., Ltd. Agent Tomi 1) Kazuo Procedural Amendment (voluntary) June 10, 1980 Director General of the Patent Office Shima 1) Haruki Tono1, Indication of the case 3, Relationship of the person making the amendment to the case Patent Applicant V Washi No. 5-2 Otemachi-chome, Chiyoda-ku, Tokyo Name (626) Mitsubishi Metals Corporation Representative Yoshihiro Inai 4, Agent Spontaneous (1) Specification, page 7, Detailed Description of the Invention, Section 11
Insert the following description between line 12 and line 12.

``As mentioned above, the Si component has a deoxidizing effect, so when it is used as a deoxidizing agent, it may be contained as an unavoidable impurity in a range of less than 0.1 parts. In this case, the total content, including the content of unavoidable impurities, should be 0.19b or more.'' (2) Specification, page 7, Detailed Description of the Invention, 3rd from the bottom. Insert the following statement between the two lines.

``Also, since the Mn component has a deoxidizing and desulfurizing effect as mentioned above, when it is used as a deoxidizing and desulfurizing agent, it is treated as an unavoidable impurity in the range of less than 0.1 modulus, just like the Si component. However, in this case as well, the ingredients should be adjusted so that the total content, including the content of unavoidable impurities, is 1% or more.

Claims (4)

[Claims] (1) C: 0.55-2.0%, Si: 0.1-30%
. Mn: 0.1 to 2.0% l cr: 10 to less than 28%, Fe: 3 to 30%, W: 0.5 to l 7,
O%t Mo: 0.5-8.0%, Ti: 0.1-3
For use in engine pulp and pulp sheets for internal combustion engines, characterized in that it contains 0.1 to 3.5 parts of N1 base alloy. (2) C: 0.55-2. Ochi, Si: 0.1-3.
0%. Mn-〇1~2.0%, Cr: 10~less than 28%,
Fe: 3~30%l W: 0.5~1'7.0%
l MO: 0.5-8.0%, Ti: 0.1-3
．． 5%, AA: 0.1=3.54, further contains Nb: 0.01 to 1.5%, and the remainder is N1 and unavoidable impurities (weight %). A Ni-based alloy for engine pulp and valve seats of internal combustion engines, characterized by: (3) C: 0.55-2.0%, Inhibition: 01-3.0%
. M! 'l:0.1~2.0%, Cr:
Less than 10 to 28%, Fe: 3 to 30
%r W: 0.5-17.0chi, MO: 0.5-8
, 0%, Ti: 0.1-3.5%, Al! :01
-3.5%, further contains 1 to 1.5% of B:O, OO, and the remainder is N1 and unavoidable impurities (weight %). Ni-based alloy for valves and valve seats. (4) C: 0.55-2.0%, Si: Q, 1-3.0
blood. Mn: 0.1 to 2.0% lcr: 10 to less than 28%,
Fe: 3~30%l W: 0.5~17.0%,
MO: Q, 5-8.0 Ti, Ti: 0.1-3.5% 2M
: Contains 0.1 to 3.5%, and further contains Nl): 0.0
1 to 1.5 q6 and 1 to 1.5% of B:O, OO, with the remainder consisting of Ni and unavoidable impurities (weight %); N1-based alloy for the same valve seat.