Compression ring and its production method

Patent metadata

Field	Value
Publication number	US-9617952-B2
Application number	US-201113699465-A
Country	US
Kind code	B2
Filing date	May 24, 2011
Priority date	May 25, 2010
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

To provide a price-competitive compression ring having excellent thermal conductivity and thermal sag resistance, which can be used in a high-thermal-load environment of high-compression-ratio engines, steel identified by the material number of SUP10 in JIS G 4801, which contains small amounts of alloying elements, is used, and a piston ring wire is annealed before an oil-tempering treatment such that spheroidal cementite having an average particle size of 0.1-1.5 μm is dispersed in a tempered martensite matrix, thereby suppressing the movement of dislocation and creep even at 300° C., and improving thermal sag resistance.

First claim

What is claimed is:

1. A compression ring consisting of a composition consisting of by mass 0.45-0.55% of C, 0.15-0.35% of Si, 0.65-0.95% of Mn, 0.80-1.10% of Cr, and 0.15-0.25% of V, the balance being Fe and inevitable impurities, and spheroidal cementite having an average particle size of 0.1-1.5 μm dispersed in a tempered martensite matrix, wherein said compression ring has thermal conductivity of 35 W/m·K or more and thermal sag ratio of 4.4% or less.

2. The compression ring according to claim 1 , wherein the amount of said spheroidal cementite dispersed is 1-6% by area on a microscopically observed structure surface.

3. The compression ring according to claim 1 , having a thermal conductivity of 38 W/m·K or more, and thermal sag ratio of 4% or less.

4. A method for producing a compression ring consisting of a composition consisting of by mass 0.45-0.55% of C, 0.15-0.35% of Si, 0.65-0.95% of Mn, 0.80-1.10% of Cr, and 0.15-0.25% of V, the balance being Fe and inevitable impurities, and spheroidal cementite having an average particle size of 0.1-1.5 μm dispersed in a tempered martensite matrix, the method comprising a spheroidizing annealing step before an oil-tempering treatment step before forming said compression ring.

5. The method for producing a compression ring according to claim 4 , wherein said spheroidizing annealing step is conducted at a temperature of 600-720° C.

6. The method for producing a compression ring according to claim 4 , wherein said oil-tempering treatment step is conducted at a quenching temperature of 820-980° C. and a tempering temperature of 400-500° C.

Assignees

• Shima Yuji
• Takahashi Junya
• KAMON Ryouichi
• Kk Riken
• Tokusen Kogyo Kk

Inventors

• Shima Yuji
• Takahashi Junya
• KAMON Ryouichi

Classifications

• C21D9/40 Primary

  for rings; for bearing races · CPC title

• C22C38/02

  containing silicon · CPC title

• F02F5/00 Primary

  Piston rings, e.g. associated with piston crown · CPC title

• F16J9/26

  characterised by the use of particular materials · CPC title

• C22C38/24

  with vanadium · CPC title