JP2014111260A - Internal combustion engine combustion chamber component and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide welding material having corrosion resistance, durability, and good welding workability and composed of a single composition and with which multi-layer welding can be performed, and to provide an internal combustion engine combustion chamber component such as a valve rod on which build up welding is performed with the welding material, and to provide a method for manufacturing the internal combustion engine combustion chamber component.SOLUTION: On a combustion chamber side surface of an internal combustion engine combustion chamber component such as a valve rod and a cylinder cover, build up welding is performed with Ni-based powder alloy fo build up welding containing: 0.001 to 0.050 mass% of C; 0.01 to 0.50 mass% of Si; 0.01 to 0.50 mass% of Mn; 20.0 to 30.0 mass% of Cr; 4.0 to 12.0 mass% of Mo; 0.5 to 4.0 mass% of Nb; 0.1 to 6.0 mass% of Fe, greater than 0.8 mass% and less than or equal to 2.0 mass% in total of one or two of Al and Ti; and a remainder of Ni and unavoidable impurities.

Description

  The present invention relates to a component part of a valve rod, a cylinder cover and a piston facing a combustion chamber of an internal combustion engine, and to a method of manufacturing the combustion chamber component part. More particularly, the present invention relates to a component facing the combustion chamber of the internal combustion engine, such as a valve rod, a cylinder cover, and a piston facing the combustion chamber side of the internal combustion engine, and to a method of manufacturing the combustion chamber component facing the combustion chamber.

  Regarding each component facing the combustion chamber of the internal combustion engine, for example, an exhaust valve rod, which is one of the components of a marine internal combustion engine, is conventionally used as an austenitic heat resistant steel such as SUH31. On the contact surface, Inconel 625 (registered trademark, Cr: 20 to 23%, Fe: 5% or less, Mo: 8 to 10%, Nb + Ta: 3.15 to 4.15%, C: 0.1% or less, Mn: 0.5% or less, P: 0.015% or less, S: 0.015% or less, Al: 0.04% or less, Ti: 0.4% or less, Co: 1% or less, Ni: 58% A method of overlay welding is known.

  Further, an exhaust valve rod which is one of the constituent elements of a marine internal combustion engine is made of Nimonic 80A (C: 0.1%, Cr: 18 to 21%, Si: 1.0%, Cu: 0.2%, Fe : 3.0%, Mn: 1.0%, Ti: 1.8 to 2.7%, Al: 1.0 to 14.8%, Co: 2.0%, B: 0.008%, Zr : 0.15%, L: 0.003%, S: 0.015%, Ni: remaining), and manufacturing by forging is performed.

  In addition, an exhaust valve rod having a contact surface facing the combustion chamber of the internal combustion engine is a valve shaft for a marine or power generation diesel engine made of heat-resistant steel, and a cladding metal is applied to the contact surface. And the composition of the overlay metal is C: 0.01 to 0.50%, Si: 0.1 to 2.0%, Cr: 35 to 55%, Al + Ti: 0.5 to 2.5% N: 0.01 to 0.6%, Mn: 2% or less, V: 3% or less, Nb: 0.2 to 0.8%. Diesel engine valve stem technology containing one or more of Mo: 5% or less, W: 5% or less, Fe: 5% or less, and the balance being substantially composed of Ni + Co and inevitable impurities Is disclosed (see Patent Document 1).

  Further, the contact surface of a valve stem made of a forged material of austenitic heat-resisting steel is made of a Ni-based alloy containing Cr: 20% by weight, Mo: 10% by weight, Al + Ti: 0.5% by weight or less, and hardness. The underlaying layer having an HRC of 25 or less is deposited, and on the underlaying layer, Cr, Al, Ti, Ni are essential components, Cr: 10 to 30% by weight, Al and Ti: total amount 2.6 to 4.6% by weight, at least two selected from the group consisting of Co, Mo, W, Nb and Fe: a total amount of 0.2 to 19% by weight, and age-hardening type containing Ni as a balance component A valve stem technique is disclosed in which a Ni-based alloy is deposited and the hardness of the deposited layer is 30 to 48 in HRC (see Patent Document 2).

Japanese Patent Laid-Open No. 6-277876 Japanese Patent Laid-Open No. 11-50821

  The parts facing the combustion chamber of the internal combustion engine include the contact surface of the valve rod, the side surface of the combustion chamber of the cylinder cover, and the piston head. For example, in the case of a marine internal combustion engine, fuel is injected from a fuel injection valve obliquely installed in a cylinder cover and an explosion occurs in the combustion chamber. The temperature in the combustion chamber is determined by the fuel on the exhaust valve rod and the fuel on the side of the cylinder cover combustion chamber. The maximum temperature in the vicinity of the injection valve is about 700 ° C., and heavy fuel oil to be injected contains a large amount of V (vanadium) and S (sulfur). Corrosion under high temperature environment progresses.

  Therefore, in order to withstand high temperature corrosion, generally, a method of overlay welding Inconel 625 (registered trademark) on the contact surface of an exhaust valve rod made of austenitic heat-resistant steel such as SUH31, and an exhaust valve A method has been used in which the entire bar is manufactured by forging with Nimonic 80A.

  When Inconel 625 (registered trademark) is welded on the contact surface of an exhaust valve rod made of austenitic heat-resistant steel such as SUH31, the weldability is good and the corrosion resistance is V-attack resistance and S-attack resistance. However, there has been a problem that wear on the flaming surface tends to progress during the long-term use. This is presumably because when heavy oil burns in the combustion chamber and an explosion occurs, hard dust is generated and scattered vigorously, so that the dust collides with the surface facing the combustion chamber and wear progresses.

  In addition, when the exhaust valve stem is manufactured by forging with the Nimonic 80A, it has corrosion resistance such as S-attack resistance and V-attack resistance, and wear hardly progresses, but the material Nimonic 80A is expensive, and It is difficult to build-up welding because there is a difficulty in welding workability. Therefore, since all the exhaust valve rods must be made of Nimonic 80A, there is a problem that the cost is greatly increased.

Moreover, since the invention described in Patent Document 1 contains S and V in heavy oil used in marine diesel engines in particular, corrosion at high temperatures due to their chemical components is likely to proceed. Although attack resistance and S attack resistance are required, the “corrosion resistance” described in Table 1 of Patent Document 1 is presumed to have evaluated the V attack resistance, but from the description in paragraph [0041], The synthetic ash of 85% V ₂ O ₅ + 15% Na ₂ SO _{4 provided by} the factory is not used, and the synthetic ash of 20% V ₂ O ₅ + 80% Na ₂ SO _{4 which} is inferior in corrosive power is used for evaluation. Therefore, there is a problem that there is a concern whether it has corrosion resistance.

  In addition, in the invention of Patent Document 1, in order to prevent the paragraph [0037] from causing the hardness of the first layer to be high and causing cracking during the two-layer welding, Since there is a description that it must be changed from the second layer overlay material, there is a concern that the operator may mistakenly select the two overlay materials at the time of overlay welding. there were.

  Next, the invention of Patent Document 2 states in paragraph [0029] that “the composition of the austenitic heat-resistant steel is significantly different from that of the austenitic heat-resisting steel. In order to prevent such a problem from occurring, it is possible to form a deposit layer once on the contact surface of the austenitic heat-resistant steel valve rod, and then form the above-described deposit layer on it. In the paragraph [0030], “The material used for forming this underlayer is made of Inconel 625, and the Ni-base alloy has a hardness after build-up of 25 or less in HRC. Is preferred. " In paragraph [0023], there is a description received as nymonic 80A or U520 (expression specific to Patent Document 2) as the layer above the underlay layer. “This means that the overlay material of the first layer and the overlay material of the second layer must be changed. There is a concern that the selection of the overlay material may be wrong, which causes a problem that weld cracking is likely to occur.

  Accordingly, an object of the present invention is to provide an S-containment resistance and a V-attack resistance that are almost the same as those of the Nimonic 80A and Inconel 625 (registered trademark) having corrosion resistance, and leave a problem in durability such as wear due to use. It has a hardness exceeding that of (Registered Trademark), overcomes the difficulty of weldability that Nimonic 80A has, has good weldability as in Inconel 625 (Registered Trademark), and has a single layer overlay welding. An internal combustion engine combustion chamber component in which welding material is welded to the combustion chamber side surface of one or more components of the valve stem, cylinder cover, and piston head And a method for manufacturing the combustion chamber component.

  In order to solve the problem described in “Problems to be Solved by the Invention”, the combustion chamber component 1 of the internal combustion engine according to claim 1 is a valve rod that is a component constituting the combustion chamber 7 of the internal combustion engine. 2, C: 0.001 to 0.050 mass%, Si: 0.01 to 0.50 mass% on the side of the combustion chamber 7 of at least one of the components of the cylinder cover 4 and the piston head 6; Mn: 0.01 to 0.50 mass%, Cr: 20.0 to 30.0 mass%, Mo: 4.0 to 12.0 mass%, Nb: 0.5 to 4.0 mass%, Fe: 0.1 to 6.0% by mass, and one or two of Al and Ti contain a total of more than 0.8% by mass to 2.0% by mass with the balance being Ni and inevitable impurities A Ni-based overlaying powder alloy is built up.

  An internal combustion engine combustion chamber component 1 according to a second aspect of the present invention is the combustion chamber component 1 according to the first aspect, wherein after the Ni-based overlaying powder alloy is built up, an aging treatment of 10 to 20 H is performed at 600 to 900 ° C. And the subsequent hardness is HV10 = 280 or more.

  The method of manufacturing the internal combustion engine combustion chamber component 1 according to the third aspect of the present invention includes at least one of the valve stem 2, the cylinder cover 4, and the piston head 6 that are components facing the combustion chamber 7 of the internal combustion engine. As a build-up welding material, C: 0.001 to 0.050 mass%, Si: 0.01 to 0.50 mass%, Mn: 0.01 To 0.50 mass%, Cr: 20.0 to 30.0 mass%, Mo: 4.0 to 12.0 mass%, Nb: 0.5 to 4.0 mass%, Fe: 0.1 to 6 Ni base meat containing 0.0 mass% and containing 0.8 to 2.0 mass in total with one or two of Al and Ti, the balance being Ni and inevitable impurities Powder plasma welding is performed using prime powder alloy, and before the powder plasma welding, without preheating Start the welding, carried out multilayer buildup on the same overlay welding material, and performing aging treatment 10~20H at 600 to 900 ° C. After the powder plasma welding.

  Since the internal combustion engine combustion chamber component 1 according to claim 1 is excellent in the weldability of the Ni-based overlaying powder alloy according to claim 1, for example, for an exhaust valve rod 2 of a marine internal combustion engine, The exhaust valve rod 2 itself does not have to be integrally formed by forging as in the case of Nimonic 80A, and overlay welding can be performed on the contact surface 3 of the exhaust valve rod 2 made of heat-resistant steel such as SUH31. As compared with the exhaust valve rod 2, the cost can be greatly reduced.

Further, it has an S attack resistance about 100 times that of the S attack value 4.1 mg / cm ² (41 g / m ² ) described in paragraph [0025] of Patent Document 2, and a V attack value of 35.1 mg / cm 2. ² (351 g / m ² ), which has a V attack resistance approximately 10 times greater than that of 351 g / m ^2, and has an effect of having a corrosion resistance substantially equal to the S attack value and V attack value of the mnemonic 80A.

  The internal combustion engine combustion chamber component 1 according to claim 2 has the same effects as the invention according to claim 1. The hardness of the present invention can be at least 50 Vickers hardness higher than the hardness HV10 = 224 level of Inconel 625 (registered trademark), and the effect of significantly reducing wear due to use. Play.

  The method of manufacturing the internal combustion engine combustion chamber component 1 according to claim 3 is capable of build-up welding with a single build-up welding material, so there is no concern that an operator mistakenly uses the build-up welding material, and weld cracking occurs. There is an effect that there is no concern about the occurrence of. In addition, since preheating is not performed, the construction time can be shortened and energy can be saved.

It is a schematic diagram of the component which comprises the combustion chamber of the internal combustion engine of this invention. (A) is a micrograph showing the microstructure of the alloy A of the present invention, and (b) is a micrograph showing the microstructure of the comparative alloy 2. It is explanatory drawing which shows the relationship between Al, Nb, and hardness in the overlay-welded alloy matrix. It is explanatory drawing which shows the relationship between Ti, Nb, and hardness in the overlay-welded alloy matrix. It is explanatory drawing which shows the build-up thickness and Vickers hardness before and after an aging treatment.

  As shown in FIG. 1, the components constituting the combustion chamber 7 of the internal combustion engine according to the present invention are the components constituting the combustion chamber 7 of the internal combustion engine, such as the valve stem 2, the cylinder cover 4, and the piston head 6. C: 0.001 to 0.050 mass%, Si: 0.01 to 0.50 mass%, Mn: 0.01 to 0.50 mass on the side of the combustion chamber 7 of at least one of the components. %, Cr: 20.0-30.0 mass%, Mo: 4.0-12.0 mass%, Nb: 0.5-4.0 mass%, Fe: 0.1-6.0 mass% A Ni-based overlaying powder alloy containing 0.8% by mass or more and 2.0% by mass in total of one or two of Al and Ti, the balance being Ni and inevitable impurities (Hereinafter, it may be described as an alloy of the present invention).

  The present invention is an internal combustion engine combustion chamber component in which at least one of the valve rod 2, the cylinder cover 4 and the piston head 6 constituting the internal combustion engine is welded to the surface on the combustion chamber 7 side. 1.

  Further, the components of the combustion chamber 7 of the internal combustion engine according to the present invention are subjected to aging treatment at 600 to 900 ° C. for 10 to 20 H after the Ni-based overlaying powder alloy is built up, and the hardness thereafter HV10 = 280 or more.

  The components of the combustion chamber 7 of the internal combustion engine according to the present invention include a valve rod 2 having a contact surface 3 facing the combustion chamber 7 of an internal combustion engine for ships, automobiles, etc., and combustion including the area around the fuel injection valve 5. It consists of a cylinder cover 4 having a side surface of the chamber 7 and a piston head 6.

  In addition, the side surface of the combustion chamber 7 of at least one component of each component has corrosion resistance in a high-temperature environment due to V or S generated by combustion or explosion of fuel oil obtained from petroleum such as heavy oil. Then, build-up welding is performed on a Ni-based overlaying powder alloy (the alloy of the present invention) having a hardness that makes it difficult to cause wear due to hard dust collision caused by combustion or explosion of fuel oil obtained from petroleum such as heavy oil.

  The reasons for limiting the range of the content of each chemical component of the Ni-based overlaying alloy (invention alloy) will be described below.

  C: 0.001 to 0.50 mass%. C combines with Cr, Ti, and Nb to form carbides, and has the effect of increasing high temperature strength and providing wear resistance. If the amount is less than 0.001% by mass in the alloy, the above effect cannot be obtained. If the content exceeds 0.50% by mass, the corrosion resistance and heat resistance are deteriorated, so the C content is 0.001 to 0.50% by mass. .

  Si: 0.01-0.50 mass%. Si is added as a deoxidizing material, but in order to deteriorate weldability, the upper limit is made 0.50% by mass and the Si content is made 0.01 to 0.50% by mass.

  Mn: 0.01 to 0.50 mass%. Mn is added as a deoxidizing material, but the effect is saturated even when added in an increased amount, and conversely, there is a tendency to form oxides as inclusions in the material, so the upper limit is 0.50% by mass, The content is 0.01 to 0.50 mass%.

  Cr: 20.0-30.0 mass%. Since Cr is an element that forms a dense Cr oxide film and improves oxidation resistance, it is added. If the amount is less than 20.0% by mass, the effect is not sufficient, so the lower limit is 20.0% by mass, and if added over 30.0% by mass, a harmful intermetallic compound is produced, so the upper limit is 30.0% by mass.

  Mo: 4.0-12.0 mass%. Mo is added as a corrosion resistance improving element and a solid solution strengthening element. If the amount is less than 4.0% by mass, the effect is not sufficient, so the lower limit is set to 4.0% by mass, and if added over 12.0% by mass, the weldability is deteriorated and the solid solution amount is saturated. The upper limit is made 12.0% by mass in order to form corrosion and deteriorate the corrosion resistance.

  Nb: 0.5-4.0 mass%. Nb is added as an element for solid solution strengthening, precipitation strengthening, and fixing C element. If the amount is less than 0.5% by mass, the effect is not sufficient, so the lower limit is set to 0.5% by mass. When the amount is increased, the solid solution amount is saturated, and a net-like intermetallic compound is formed in the matrix to deteriorate the corrosion resistance. 4.0% by mass.

  Fe: 0.1-6.0 mass%. Fe is an element that promotes aging precipitation and contributes to cost reduction as an alternative to Ni. If the amount is less than 0.1% by mass, the effect is not sufficient, so the lower limit is set to 0.1% by mass, and when added in an increased amount, the corrosion resistance and oxidation resistance are deteriorated, so the upper limit is set to 6.0% by mass.

  Al + Ti: more than 0.8% by mass to 2.0% by mass. Both Al and Ti precipitate the γ ′ phase, that is, Ni + Al or Ni + Ti, by aging treatment, thereby causing hardening of the material. If the addition amount is small, the precipitation of the γ ′ phase is small and the expected effect cannot be obtained, so the lower limit is made 0.5 mass% in total of Al and / or Ti. On the other hand, excessive addition of Al or Ti reduces the solid solution amount of Nb in the matrix, leading to a decrease in hardness and corrosion resistance, and also increases the consistency between the γ 'phase and the matrix, reducing the matching strain and matching. Since hardening due to strain becomes insufficient, the upper limit is made 2.0 mass% in total with Al and / or Ti.

  Next, on the side surface of the combustion chamber 7 of at least one of the valve rod 2, the cylinder cover 4, and the piston head 6, which are components constituting the combustion chamber 7 of the internal combustion engine, A method for overlay welding a powder alloy will be described with respect to the exhaust valve rod 2 which is the combustion chamber component 1 for a marine internal combustion engine.

  An exhaust valve rod 2 which is a combustion chamber component 1 for a marine internal combustion engine is made of heat-resistant steel such as SUH31, and the Ni-based overlaying powder alloy is used for the contact surface 3 of the exhaust valve rod 2 to form a powder. Body plasma welding is performed without preheating the contact surface 3. At the time, the method of forming the bead of powder plasma welding is to form a bead in a spiral shape from the center of the flaming surface 3 toward the outer side when the three-layer construction is performed, and the first layer is completed. Then, on the second layer, using the Ni-based overlaying powder alloy, a bead is constructed in a spiral shape from the center of the flaming surface 3 toward the outer side, and when the second layer is completed On the third layer, a bead is spirally applied from the center of the flaming surface 3 toward the outer side using the Ni-based overlaying powder alloy. In the case of overlay welding of the fourth layer, the fifth layer, and the sixth layer, the above-described Ni-based overlaying powder alloy is similarly used to make the beads spiral.

  In addition, for the piston head 6 which is another component, a bead is spirally wound in an outward direction around the center of the surface on the combustion chamber 7 side, and for the cylinder cover 4 A linear bead is formed around the fuel injection valve 5 in parallel in a lateral direction and in a multi-layered manner, or spirally along the inner peripheral wall surface of the cylinder cover 4 on the inner wall surface on the combustion chamber 7 side from the bottom upward. When the first layer is completed, the second layer is spirally laminated from the bottom upward, and this is repeated and applied to the multilayer pile.

  The Ni-based overlaying powder alloy is overlay welded to the combustion chamber 7 side surface of the combustion chamber 7 component of an internal combustion engine for ships, automobiles, etc. according to the welding method, so that Corrosion resistance was able to have S attack value and V attack value almost equivalent to those of Nimonic 80A and Inconel 625 (registered trademark).

  Furthermore, since the aging treatment is performed under conditions of 600 to 900 ° C. after the Ni-based overlaying powder alloy is built up, it is possible to have a subsequent hardness of HV10 = 280 or more, and Inconel 625 (registered) The hardness of the trademark) was exceeded, and the wear against the collision of hard dust could be made difficult to progress.

  Next, the present invention will be described with reference to examples and comparative examples.

  Table 1 shows the components of the test pieces used in Examples or Comparative Examples. In Table 1, the test piece as an Example is shown as this invention alloy AF, and the test piece as a comparative example is shown as Comparative Alloys 1-8.

  Comparative alloy 4 is a test piece having substantially the same components as Inconel 625 (registered trademark), and comparative alloy 7 or 8 is a test piece having substantially the same components as Nimonic 80A.

  In Table 1, the test piece provided for any of the alloys A to F of the present invention and the comparative alloys 1 to 7 is formed on a columnar overlaying substrate made of SUH31 and having an outer diameter of 250 mm × thickness of 50 mm. Using a building powder alloy (alloy of the present invention), overlay welding was performed by three-layered powder plasma welding having a thickness of about 6 to 9 mm. The comparative alloy 8 is a test piece in which the powder of the Ni-based overlaying powder alloy (the alloy of the present invention) is poured into a mold without melting and solidified and solidified.

  Moreover, in Table 1, the part with an underline in a number shows that it is the quantity outside the range which prescribed | regulated content of this invention alloy. The unit of the content of each component is mass%.

  Here, in order to evaluate the weldability of all powder alloys except the comparative alloy 8 in which the powder made of Nimonic 80A was melted and hardened, the weld-welded test pieces were cut and the cross-sectional observation was performed to improve the weldability. evaluated. If cracks were not confirmed, “◯” was displayed in Table 2 because the weldability was good, and “X” was displayed in Table 2 because the weldability was poor when cracks were confirmed.

For the evaluation of hardness, a test piece was indexed from the weld overlay, and the inventive alloys A to F and comparative alloys 1 to 7 were kept at 1080 ° C. for 8 hours and air-cooled, and 700 ° C. In the case of maintaining for 16 hours, an aging treatment for air cooling after holding at 600 to 900 ° C. for 10 to 20 H was applied, and an aging treatment for holding the comparative alloy 8 and air cooling was applied, and the accuracy was measured by Vickers hardness. . The aging treatment conditions applied to the alloys A to F of the present invention and the comparative alloys 1 to 7 were as follows: the alloys A and D of the present invention and the comparative alloys 1 and 2 were kept at 600 ° C. for 20 hours and then air-cooled. Air cooling after holding at 700 ° C. for 10 hours for comparative alloys 6 and 7, Alloys B and E of the present invention and air cooling after holding for 10 hours at 750 ° C. for comparative alloys 4 and 5, Alloy C and comparative alloy of the present invention 3 is air cooling after holding at 900 ° C. for 10 hours.

  Next, as an evaluation of the corrosion resistance, a test piece was determined from the overlay welded portion, subjected to the same heat treatment as described above, and subjected to a corrosion resistance evaluation test using an S attack and a V attack. These evaluations are quantitative evaluations by corrosion weight loss.

As a corrosion resistance evaluation test by S attack and V attack, the S attack test was performed by embedding a test piece of 16 mm × 12 mm × 4 mm in synthetic ash of 90% Na ₂ SO ₄ + 10% NaCl, and then at 800 ° C. for 20 hours. The results are shown in Table 2. In the V attack test, a test piece having a size of 16 mm × 12 mm × 4 mm was embedded in 85% V ₂ O ₅ + 10% Na ₂ SO ₄ synthetic ash, and then maintained at 800 ° C. for 20 hours to reduce the corrosion weight. The results are shown in Table 2.

  From Table 2, when the weldability evaluation is seen, the weldability was good in any of the test pieces of alloy names A to F which are the alloys of the present invention. The comparative alloy was a component equivalent to Nimonic 80A, and the weldability of comparative alloy 7 having a C content exceeding 0.50% by mass was evaluated as poor. Here, since the comparative alloy 8 is not subjected to overlay welding, it is out of the evaluation target of weldability.

  From Table 2, it can be seen that the corrosion resistance, V attack resistance, is compared to Inconel 625 (Registered Trademark) in any of Alloys A to F of the present invention and Comparative Alloys 1 to 8. In addition, it is shown that the comparative alloy 8 made of the same component as the Nimonic 80A has the V attack resistance equivalent to the V attack resistance.

  Next, looking at the S-attack resistance, from Table 2, all of the alloys A to F of the present invention are composed of the comparative alloy 4 composed of the same component as Inconel 625 (registered trademark) or the component equivalent to the Nimonic 80A. It has been shown to have S attack resistance equivalent to that of Comparative Alloy 8. On the other hand, looking at the comparative alloy, comparative alloys 1, 2, 3 or Mo whose Mo content is 12.0% by mass or less, Nb content is 4.0% by mass or less and the total content of Al + Ti exceeds 2.0% by mass 7. Comparative alloy 5 having a Nb content of 4.0% by mass or less, a total content of Al + Ti of 2.0% by mass or less and a Mo content of more than 12.0% by mass, or a Mo content of 12.0% The comparative alloy 6 in which the total content of Al + Ti is 2.0% by mass or less and the Nb content is more than 4.0% by mass is less than 5% by mass, and the S-attack resistance is any of the alloys A to F of the present invention. Inferior evaluation is shown at a level of about 10 times to about 100 times.

  Looking at the hardness, from Table 2, the alloys Al to Ti of the present invention having a total Al + Ti content of 0.5% by mass or more, Comparative Alloys 1 to 3, and Comparative Alloys 5 to 8 are all Al + Ti. It is shown that an evaluation that the hardness HV10 = 224 of the comparative alloy 4 having a content of less than 0.5% by mass is increased by at least 50 Vickers hardness is obtained. Further, the hardness is higher by about 30 in terms of Vickers hardness (HV10) than the welded Nimonic 80A. From these facts, in all of the alloys A to F of the present invention, by setting the total content of Al + Ti to 0.5% by mass or more, Inconel 625 (registered trademark) has a problem in durability due to the progress of wear due to long-term use. The durability could be improved as compared with Comparative Alloy 4 having the same component as).

  Next, in order to observe hardening by aging treatment at 600 to 900 ° C. and 10 to 20 H, Vickers hardness before and after heat treatment was measured, and the result is shown in Table 3 or FIG. Table 3 shows the Vickers hardness of the alloy A of the present invention, and the unit of the Vickers hardness is HV10.

  From Table 3 or FIG. 5, it was found that the Vickers hardness after the heat treatment was higher by about 100 in the Vickers hardness e after the heat treatment than in the Vickers hardness e before the heat treatment even when the build-up thickness was different. It is shown.

  Next, powders of the alloys of the present invention and comparative alloys in which the respective contents of C, Si, Mn, Cr, Nb and Mo are set to be substantially the same, and the respective contents of Al and Ti are set to be different. The chemical components of the matrix 15, the granular compound 16 or the net-like intermetallic compound (also referred to as a network compound) 17 were analyzed by state observation, structure welding by age-hardening and SEM observation after age hardening. Table 3 shows the chemical components of the matrix A, the powder compound 16 or the net-like intermetallic compound 17 of the alloy A of the present invention, the comparative alloys 1 and 2, and the alloy A of the present invention in FIG. (B) shows a microstructural photograph of the comparative alloy 2 by observation of the structure by SEM. The unit of Table 4 is mass%.

  FIG. 2A shows an SEM photograph 10 of the alloy A of the present invention. In FIG. 2A of the alloy A of the present invention having a total content of Al + Ti of 2.0 mass or less, the light gray portion is the matrix 15 and the black granular portion is the portion where the granular compound 16 appears. It is estimated that a small area around the granular compound 16 is corroded and dropped off. On the other hand, FIG. 2B shows an SEM photograph 11 of the comparative alloy 2. In FIG. 2B of the comparative alloy 2 having a total content of Al + Ti exceeding 2.0 mass, the dark gray portion is the matrix 15 and the light gray striped portion is the range in which the net-like intermetallic compound 17 appears. It is estimated that a wide range of the net-like intermetallic compound 17 is corroded and dropped off. Accordingly, the alloy A of the present invention has a narrow range in which the particulate compound 16 is generated and drops off, and the comparative alloy 2 has a wider range in which the net-like intermetallic compound 17 is generated and drops off. Since the progress is presumed to be fast, it is desirable not to allow the net-like intermetallic compound 17 to appear. For that purpose, the total content of Al + Ti is preferably 2.0 mass or less.

  From Table 4, in both the alloy A of the present invention and the comparative alloys 1 and 2, the solid solution amount of Nb and Mo is small in the matrix 15, and the granular compound 16 or the net intermetallic compound 17 is Ni, Cr, Mo. And a compound consisting of Nb. From this, it is considered that the granular compound 16 or the net-like intermetallic compound 17 is generated by Nb or Mo that could not be completely dissolved in the matrix 15.

  Further, from Table 4, the Mo content in the matrix 15 in the alloy A and the comparative alloys 1 and 2 is about 8 to 9 regardless of the total content of Al and Ti. It is the mass% and has shown almost the same content. On the other hand, the Nb content in the matrix 15 was 3.86% by mass in the powder state, but 2.50% in the case of the alloy A of the present invention in which the total content of Al and Ti is 1.64% by mass. In the case of Comparative Alloy 1 with a total content of Al and Ti of 2.09% by mass and Comparative Alloy 2 with a total content of Al and Ti of 5.01% by mass 1.42% by mass, the solid solubility of Nb in the matrix 15 depends on Al and Ti to be added, and the amount of Nb solid solution tends to decrease as the amount added increases. It is considered that the Nb that cannot be completely dissolved in the matrix 15 generates a net-like intermetallic compound in which the granular compound 16 or the network compound 17 is formed. Further, from FIG. 2, when the total content of Al + Ti is 2.0 mass or less, a granular compound 16 is generated, and when the total content of Al + Ti is more than 2.0 mass, a net-like intermetallic compound 17 is generated. Furthermore, as the total content of Al + Ti increases, the range of the net-like intermetallic compound 17 becomes wider. From this, the range of the net intermetallic compound of the comparative alloy 1 having a total content of Al + Ti of 3.09% by mass is small, and the net shape of the comparative alloy 2 having a total content of Al + Ti of 5.01% by mass. The range of intermetallic compounds is large.

  Table 4 shows that the granular compound 16 or the net-like intermetallic compound 17 is a Ni + Cr + Mo + Nb-based compound from the result of component analysis. Therefore, when the total content of Al + Ti exceeds 2.0% by mass, the matrix 15 This indicates that the amount of Nb solid solution decreases, Nb is combined with other elements and distributed as a compound, and a Ni + Cr + Mo + Nb compound is precipitated.

In Table 2, the hardness of the alloy A of the present invention is HV10 = 320, the comparative alloy 1 is HV10 = 409, and the comparative alloy 2 is HV10 = 585. In Table 2, the S attack corrosion amount of the alloy A of the present invention is 0.34 g / m ² / H, the comparative alloy 1 is 216.49 g / m ² / H, and the comparative alloy 2 is 387.69 g / H. It is shown to be m ² / H. From these facts, it is shown that when the total content of Al and Ti exceeds 2.0% by mass, a large amount of net-like intermetallic compound 16 precipitates and the hardness increases, but the S attack corrosion amount increases. It was.

  In FIG. 3, the relationship between the Al content in the matrix 15 and the Nb content in the matrix 15 is indicated by a line a, and the relationship between the Al content in the matrix 15 and the aging hardness is indicated by a line b. The relationship between Al, Nb, and hardness is shown. Further, in FIG. 4, the relationship between the Ti content in the matrix 15 and the Nb content in the matrix 15 is indicated by a line c, and the relationship between the Ti content in the matrix 15 and the age hardness is indicated by a line d. The relationship between Ti and Nb in the matrix 15 and the hardness is shown. FIG. 3 or FIG. 4 shows that when Al or Ti increases, the age hardness of the alloy increases, but the amount of Nb in the matrix 15 tends to decrease. This is considered that the increase in Al and Ti promotes the formation of the net-like intermetallic compound 16 which is the network-like compound 17 and deteriorates the corrosion resistance such as S attack resistance.

  Therefore, the valve rod 2 having the flaming surface 3 facing the combustion chamber 7 of the internal combustion engine for marine use or automobile use, the cylinder cover 4 having the side surface of the combustion chamber 7 including the peripheral region of the fuel injection valve 5, and the piston head 6 As shown in Table 2, the components of the combustion chamber 7 of the internal combustion engine in which the alloy of the present invention is welded to at least one of the components of the present invention have good welding quality, V attack resistance and resistance. The S attack property is equivalent to the corrosion resistance of Inconel 625 (registered trademark) and Nimonic 80A, the hardness is at least 50 or more Vickers hardness (HV10) than Inconel 625 (registered trademark), and the Nimonic 80A is welded by overlay welding. A higher Vickers hardness (HV10) of 30 was shown.

DESCRIPTION OF SYMBOLS 1 Combustion chamber component of internal combustion engine 2 Valve rod 3 Contact surface 4 Cylinder cover 5 Fuel injection valve 6 Piston head 7 Combustion chamber 10 SEM photograph 11 SEM photograph 15 Matrix 16 Granular compound 17 Reticulated compound (net-like intermetallic compound)

Claims (3)

  C: 0.001 to 0.050% by mass, Si on the side of the combustion chamber of at least one of the valve rod, cylinder cover, and piston head, which are components constituting the combustion chamber of the internal combustion engine : 0.01 to 0.50 mass%, Mn: 0.01 to 0.50 mass%, Cr: 20.0 to 30.0 mass%, Mo: 4.0 to 12.0 mass%, Nb: 0 0.5 to 4.0% by mass, Fe: 0.1 to 6.0% by mass, and a total of more than 0.8% by mass to 2.0% by mass of one or two of Al and Ti An internal combustion engine combustion chamber component comprising a Ni-based overlaying powder alloy comprising Ni and the balance of Ni and inevitable impurities.   2. The aging treatment of 10 to 20 H is performed at 600 to 900 ° C. after the Ni-based overlaying powder alloy is built up, and the subsequent hardness is HV10 = 280 or more. Internal combustion engine combustion chamber components.   As a build-up welding material, C: 0.001 is formed on the surface of the combustion chamber side of at least one of the valve rod, cylinder cover, and piston head, which are components facing the combustion chamber of the internal combustion engine. To 0.050 mass%, Si: 0.01 to 0.50 mass%, Mn: 0.01 to 0.50 mass%, Cr: 20.0 to 30.0 mass%, Mo: 4.0 to 12 0.0% by mass, Nb: 0.5 to 4.0% by mass, Fe: 0.1 to 6.0% by mass, and one or two of Al and Ti in total 0.8 Powder plasma welding is performed using a Ni-based overlaying powder alloy containing more than 2.0% by mass and the balance being Ni and inevitable impurities, and preheating is performed during the powder plasma welding. The welding is started, and multilayer overlaying is performed with the same overlay welding material, and the powder plasma welding is performed. Engine combustion chamber components manufacturing method, which comprises carrying out the aging treatment 10~20H at 600 to 900 ° C. to.

Images