JP2006316912A - Piston ring having ion plating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piston ring using steel, an aluminum alloy, or a Ti alloy as a matrix material with superior adhesiveness to a hard ion plating film, and capable of easily reducing roughness of a film surface, and a pretreatment method suiting the piston ring. <P>SOLUTION: A substrate surface for the ion plating film is processed to a ten point mean roughness (hereafter displayed in Rz) of 0.5-2.0Rz by sandblasting using hard ceramics particles such as alundum, carborundum, or the like with a mean particle diameter of 3-20μm. Then the hard ion plating film formed by at least one type selected from Ti or/and Cr, C, N, and O is formed on the substrate surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steel, aluminum alloy or Ti alloy piston ring having a hard ion plating film on a sliding surface and a method for producing the same, and in particular, hard ions comprising Ti and / or Cr and C, N, O. The present invention relates to a piston ring having a plating film and a pretreatment method thereof.

  Conventionally, a hard Cr plating film has been used as a wear-resistant film on the sliding surface of the sliding member. However, due to environmental problems with hexavalent Cr ions, hard ion plating films and nitriding films have been used instead of hard Cr plating films. In particular, in piston rings of internal combustion engines, in order to obtain a nitride layer with excellent wear resistance, a stainless steel material with high Cr content must be used as a base material. Since harmful chemicals such as cyanide are used, hard coatings such as TiN and CrN by ion plating, which is a pollution-free treatment, have come to be used as an alternative to hard Cr plating coatings. However, the wear-resistant film used for the sliding surface of the piston ring requires high adhesion, and various devices have been made.

  Japanese Patent Application Laid-Open No. 61-87950 (Patent Document 1) relates to a piston ring having a sliding surface with a fine mixed film of metal chromium and chromium nitride by ion plating. In applying the ion plating film to the outer peripheral surface of the piston ring, it is described that the mixed structure is formed in consideration of the flexibility and thermal expansion coefficient of the film in order to ensure the adhesion of the film. Further, this patent also discloses that ion bombardment of Ar gas is performed immediately before ion plating in order to ensure adhesion of the film. However, in this method, the hard ion plating film is limited, and the bombardment by Ar gas ions used in the present invention has a low effect of removing surface oxides of steel, aluminum alloy and Ti alloy, and is expected not to improve adhesion. There is a problem that you can't.

  Japanese Patent Laid-Open No. 63-42362 (Patent Document 2) discloses that a nitride layer, a carbonized layer, and a carbonitride layer are formed on a steel base material, and then nitrides, carbides, and carbonitrides of Group 4a and Group 5a are formed by ion plating. It is a patent characterized in that metal bombarding is performed when coating. Instead of the Ar ion bombardment of the above patent, metal ion bombardment is used. Since metal ions have higher energy than Ar ions, it is effective for the sputter cleaning of the base, and the metal ions are the base layer. Therefore, the adhesion of nitrides, carbides, and carbonitrides of the 4a group and 5a group formed thereon can be increased. However, metal ion bombardment is limited to arc ion plating equipment, and high energy metal ion bombardment requires a long bombard time to remove foreign matters such as surface oxides of steel, aluminum alloy and Ti alloy. , Remarkably raise the base material temperature. Therefore, there is a problem that the base material is softened or deformed, and the piston ring needs to use a heat-resistant material as the base material. In the low energy metal bombardment, low energy metal ions may form a film as it is, and on the contrary, the adhesion of the film is hindered.

  Japanese Patent Laid-Open No. 7-292458 (Patent Document 3) is a sliding member in which a coating made of Cr and nitrogen is formed on the sliding surface of a sliding member made of cast iron or steel, and an ion plating coating made of Cr and nitrogen. The base surface is adjusted to an average surface roughness of 2 to 8 μm by sand sand blasting. The surface roughness is obtained by changing the spraying pressure and frequency of hard sand sandblasting materials such as alumina and carborundum with a particle size of # 180 by sand sandblasting, thereby obtaining an ion plating film with excellent adhesion. It is supposed to be done. Certainly, it is possible to remove foreign substances such as surface oxides of steel, aluminum alloy and Ti alloy by using this method, but the surface roughness of the base material to be blasted becomes extremely rough, so that The roughness of the hard ion plating film formed on the top also becomes rough. As a result, the hard ion plating film requires a polishing process on the surface of the hard ion plating film in order to prevent wear of the counterpart material, and the polishing process takes time because the film is hard. Further, the ion plating film must be formed thick enough for the polishing process, and the ion plating time must be increased. In the case of low-hardness steel, aluminum alloy or Ti alloy, the hard sand-sand blasting material pierces the base material (Photo 1). When worn, the hard sandblast material that has been pierced may be exposed, and the mating material may be worn out or scuffing may occur. Furthermore, when the ion plating film has a columnar crystal structure due to the rough surface roughness, pores are easily formed at the boundary of the crystal structure, and the film strength is low, so the film is likely to be weak against abrasion. There is also a problem.

  Japanese Patent Application Laid-Open No. 2000-12869 (Patent Document 4) relates to a sliding member used at a high temperature and a high load with an AL alloy as a counterpart material and a method for manufacturing the same, and has a sliding surface with a size of 0.5 to 5 μm. It is characterized by a diamond-like carbon film having a surface structure deposited in a lumped shape. Then, diamond having a surface structure deposited in a ridge shape of 0.5 to 5 μm by finishing the sliding surface to a surface roughness of 0.05 to 1 μmRa by lapping or sandblasting and then diamond coating. Disclosed is a like carbon film. However, there is no disclosure regarding the sandblasting method or any description of coatings other than the diamond-like carbon film.

JP-A-61-87950 JP-A-63-42362 JP-A-7-292458 JP 2000-12869 A

  As described above, in the conventional technology, in the piston ring having the hard ion plating film on the sliding surface of the steel, aluminum alloy or Ti alloy sliding member, the ion plating film is formed with good adhesion. A highly efficient pretreatment method has not been found. In particular, there was nothing in the case of a piston ring having a base material of steel, aluminum alloy or Ti alloy that has low hardness at room temperature or is likely to cause strength and deformation due to temperature rise. In view of the above circumstances, the present invention provides productivity, cost, heat as a pretreatment method for forming a hard ion plating film having excellent adhesion on a sliding surface of a steel, aluminum alloy or Ti alloy piston ring. To provide a piston ring made of steel, aluminum alloy or Ti alloy having a hard ion plating film having excellent adhesion on the surface of the sliding part using a sandblasting method with few problems such as deformation, and a method for producing the same. Objective.

  The piston ring of the first invention of this application is a piston ring made of steel, aluminum alloy or Ti alloy having a hard ion plating film of 1 to 30 μm on at least a sliding surface, and the base surface of the ion plating film is hard 10 point average roughness (hereinafter expressed as Rz) is processed to 0.5 to 2.0 Rz by sandblasting of the particles, and the surface of the base is an alundum or carbander having an average particle diameter of 3 to 20 μm Are processed by sand blasting using hard ceramic particles such as the above, whereby high adhesion of the hard ion plating film can be obtained. The hard ion plating film is formed of at least one selected from Ti and / or Cr and C, N, and O, and the sliding surface exhibits sufficient wear resistance.

  The second invention of the present application is a manufacturing method of a piston ring made of mild steel, aluminum alloy or Ti alloy, and the sliding surface of the sliding member is a sand using hard ceramic particles such as alundum or carborundum having an average particle diameter of 3 to 9 μm. The first step of processing to 0.5 to 2.0 Rz by sandblasting, the second step of air blowing or / and organic solvent ultrasonic cleaning of the sliding parts, and ion bombardment in the vacuum chamber of the ion plating apparatus Or at least a sand-sandblasted sliding surface is coated with a film comprising at least one selected from Ti and / or Cr and C, N, and O by an ion plating method. It is a manufacturing method of a ring.

  By using the pretreatment method of the present invention, it is made of steel, aluminum alloy or Ti alloy which has excellent adhesion of hard ion plating film, no piercing of sandblast particles, and easy surface roughness reduction. You can get a piston ring.

1. Piston ring The piston ring of the present invention is made of steel, aluminum alloy or Ti alloy. The sliding surface may be hardened by a heat treatment such as carburizing or nitriding, or a hard plating film may be formed by wet plating or the like.

  The base surface on which the hard ion plating film is formed is processed to 0.5 to 2.0 Rz by sand blasting using hard ceramic particles such as alundum or carborundum having an average particle diameter of 3 to 20 μm. The surface of the base adheres much to the process-affected layer, oxide layer, dirt, etc. in the previous step, but is sufficiently removed by sandblasting. At the same time, by using a hard blast material having an average particle diameter of 3 to 20 μm, it is not necessary to pierce the sand blast material into the base material.

A hard ion plating film made of at least one selected from Ti and / or Cr and C, N, and O is formed on the outer sliding surface. These films have lower internal stresses than other films, and adhere well to the surface of steel, aluminum alloy or Ti alloy processed to 0.5 to 2.0 Rz. If necessary, the surface of these hard ion plating films may be subjected to surface polishing such as lapping, but since the surface roughness is fine, the surface roughness of the ion plating film after film formation is fine and can be used as it is. Wide range.

2. Piston Ring Manufacturing Method The piston ring manufacturing method of the present invention is first set so as to be easily sandblasted using a tool or the like, and the sliding surface of a steel, aluminum alloy or Ti alloy piston ring is averaged. The surface roughness is processed to 0.5 to 2.0 Rz by sandblasting using hard ceramic particles such as alundum or carborundum having a particle size of 3 to 20 μm.

  Since the sand blast processing method uses a large number of particles although each particle energy is small, the entire sliding surface can be processed into a uniformly rough processed surface. In the present invention, sand particles having a fine particle diameter of 3 to 20 μm in average particle diameter are used for sand blasting, so that the collision energy of the sand particles to the base surface is small, and the mother material such as steel, aluminum alloy or Ti alloy is used. Even on the surface of the material, the surface roughness of the base can be made as fine as 0.5 to 2.0 Rz, and there is no piercing of sand particles on the surface. Even if it exists, the degree of piercing is light (the depth is shallow), so it can be easily taken by subsequent air blow or ultrasonic cleaning, and is not taken into the boundary of the film. When hard ceramic particles are used as the sand blasting material, the work-affected layer (plastic fluidized layer), oxide layer and dirt on the surface can be easily removed by grinding. The hard ball shot material is not desirable because it causes deformation of the base material without taking a work-affected layer. The same applies to other glass beads. When the average particle size of the sandblasting material is 3 μm or less, the surface grinding ability is lacking and the sandblasting time becomes long and the productivity is poor. When the average particle size is 20 μm or more, the base material base roughness becomes too large, and the surface roughness of the ion plating film formed thereon becomes too rough. It's not a good idea because it requires a longer time. In addition, there is a problem that sandblast particles are pierced more.

  After sandblasting, the piston ring is air blown and / or ultrasonically cleaned with an organic solvent to remove sand particles adhering to the surface. Sand particles are less likely to pierce the base material, and many are thought to be attached by static electricity and can be easily removed by air blow. If the air and sand particles used during sandblasting are heavily contaminated, the organic solvent degreasing can be continued to further improve the adhesion of the hard ion plating film, but this is not desirable due to environmental problems.

  After that, it is selected from Ti or / and Cr and C, N, and O at least on the sand-sandblasted sliding surface with or without ion bombardment set in the vacuum chamber of the ion plating apparatus together with the jig. A film comprising at least one kind is coated by an ion plating method. In general, ion bombardment is preferable because Ar ion bombardment has a low temperature rise of the object to be processed. However, in the case of arc ion plating, metal ion bombardment may be performed if bombardment is performed for a short time. Long metal ion bombardment is undesirable because it raises the base material excessively.

  As an ion plating method, any one of arc ion plating, HCD ion plating, etc. can be used. However, when droplets in the film are not satisfactory, the HCD method is used when higher adhesion is required or Ti and Cr are used. The arc ion plating method is suitable when the composite compound film is required.

  Although the formed hard ion plating film depends on the film thickness, the average surface roughness is 0.5 to 2.0 Rz. In the conventional case using coarse sand sand blast particles disclosed in JP-A-7-292458. It will be much finer than that. Therefore, even when it is necessary to make the surface of the hard ion plating film finer by lapping polishing, buffing or the like, the polishing allowance is small and processing can be performed in a short time. In addition, since the machining allowance due to surface processing is reduced, the ion plating thickness can be reduced, and the productivity of not only the ion plating process but also the piston ring itself is improved. Specific examples will be described below.

  Approximately 100 steel piston rings (nominal outer diameter φ73mm x thickness 1.0mm x width 2.5mm) formed from silicon chrome steel wire (SWOSC-V) are aligned and tightened with bolts. A cylindrical workpiece was constrained from both ends. This object to be treated was attached to a sandblasting device and rotated, and the outer peripheral surface of the piston ring was sandblasted. The outer peripheral surface roughness of the base material was changed by changing the blast material type, the average particle diameter, and the projection pressure. After sandblasting, the sprayed powder and grinding powder adhering to the surface were removed by air blowing. Thereafter, the surface roughness was measured with a roughness meter.

  Two types of sand, GC and WA, were used as the sand, and the average particle size was 1 μm, 3 μm, 6 μm, and 20 μm. As comparative examples, those having an average particle size of 30 μm and 50 μm described in the prior art patents were also used. Table 1 shows the results of measuring the surface of the piston ring with a roughness meter after sandblasting and sandblasting.

  After measuring the surface roughness, it was put into an arc ion plating apparatus, subjected to predetermined preheating and bombardment, and then a CrN film of 22 to 25 μm was formed. After cooling, it was taken out from the arc ion plating apparatus. The ion plating conditions are as follows.

1. Preheating Temperature: 400 ° C Time: 60 minutes Bombard Ion Bombard
Bias voltage: 800V
Time: 10 minutes
Arc current: 160A
3. CrN coating Nitrogen gas pressure: 10 mtorr
Arc current: 160A
Time: 4 hours

  After disassembling the cylindrical piston ring after ion plating, the cast ring is used to wrap the outer peripheral surface of the piston ring (CrN film surface) with SiC abrasive slurry having an average particle diameter of 3 μm for 30 seconds or 60 seconds. Went. After removing the dirt, the surface roughness of the outer peripheral surface of the piston ring was measured again.

  Table 2 shows the results of surface roughness after lapping. The arc ion plating apparatus is a 13-axis self-revolving type apparatus, and since the piston ring processed under the blasting conditions shown in Table 1 can be simultaneously formed, it can be said that there is no coating variation due to film formation.

表２より下記のことが言える。

From Table 2, the following can be said.

  1. When a blasting material with an average particle size of 1 to 20 μm is used, it can be reduced to Rz 0.8 μm (with piston ring Rz 0.8 μm or less is necessary when considering mating material wear) by lapping for 30 seconds. As a result, productivity in the lapping process is improved as compared with the conventional techniques (Comparative Examples 5 to 6).

  In the case of lapping for 60 seconds, the surface roughness is almost the same in Examples and Comparative Examples 1 to 4.

  The adhesion of the film is not a problem when the average particle size is 6 μm or more with the prior art and Examples 1 to 4 and the blast particles of the present application, but there is a problem that peeling or fine chipping occurs when the particle size is 3 μm or less.

  As mentioned above, GCN and WA with an average particle diameter of 6-20 μm are used as sandblasting material, and the outer peripheral surface of the piston ring is sandblasted, so that the adhesion of the CrN ion plating film is good and the wrapping is performed in a short time. By processing, the surface roughness can be reduced to Rz 0.4 μm or less.

Claims (4)

  A sliding part made of steel, aluminum alloy or Ti alloy having a hard ion plating film of 1 to 30 μm on at least the sliding surface, and the surface of the ion plating film has an average roughness of 10 points (hereinafter Rz The piston ring is processed to 0.5 to 2.0 Rz.   2. The piston ring according to claim 1, wherein the base surface of the ion plating film is processed by sand blasting using hard ceramic particles such as alundum or carborundum having an average particle diameter of 3 to 20 [mu] m.   The piston ring according to claim 1, wherein the hard ion plating film is a film made of at least one selected from Ti and / or Cr and C, N, and O.   This is a method of manufacturing a sliding member made of steel, aluminum alloy or Ti alloy, and the sliding surface is 10 points average roughness by sandblasting using hard ceramic particles such as alundum or carborundum having an average particle diameter of 3 to 20 μm. .First step for processing to 5 to 2.0 Rz, second step for air blowing or / and ultrasonic cleaning of organic solvent for the sliding component, or whether or not ion bombardment is performed in the vacuum chamber of the ion plating apparatus A steel characterized in that at least a sliding surface subjected to sandblasting is coated with a film mainly composed of at least one selected from Ti and / or Cr and C, N, O by an arc ion plating method, A method for producing an aluminum alloy or Ti alloy piston ring.