Compression ring and its production method

Patent metadata

Field	Value
Publication number	US-9599223-B2
Application number	US-201214128459-A
Country	US
Kind code	B2
Filing date	Jun 21, 2012
Priority date	Jun 22, 2011
Publication date	Mar 21, 2017
Grant date	Mar 21, 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 SKS93 in JIS G 4404 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.

First claim

What is claimed is:

1. A compression ring having a composition consisting of by mass 1.00-1.10% of C, 0.50% or less of Si, 0.80-1.10% of Mn, and 0.20-0.60% of Cr, the balance being Fe and inevitable impurities, with spheroidal cementite having an average particle size of 0.1-1.5 μm dispersed in a tempered martensite matrix.

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 35 W/m·K or more, and a thermal sag ratio of 4% or less.

4. A method for producing a compression ring having a composition consisting of by mass 1.00-1.10% of C, 0.50% or less of Si, 0.80-1.10% of Mn, and 0.20-0.60% of Cr, the balance being Fe and inevitable impurities, with spheroidal cementite having an average particle size of 0.1-1.5 μm dispersed in a tempered martensite matrix, the method comprising:
providing a steel wire having a composition consisting of by mass 1.00-1.10% of C, 0.50% or less of Si, 0.80-1.10% of Mn, and 0.20-0.60% of Cr, the balance being Fe and inevitable impurities;
subjecting the steel wire to an annealing step at a temperature of 600-750° C.;
subjecting the steel wire to an oil-tempering treatment step at a quenching temperature of 820-930° C. and a tempering temperature of 400-500° C. after the annealing step, and then;
forming the steel wire into said compression ring, so that the spheroidal cementite having an average particle size of 0.1-1.5 μm is dispersed in a tempered martensite matrix in the compression ring.

5. A compression ring having a composition consisting of by mass 1.00-1.10% of C, 0.50% or less of Si, 0.80-1.10% of Mn, and 0.20-0.60% of Cr, the balance being Fe and inevitable impurities, with spheroidal cementite having an average particle size of 0.1-1.5 μm dispersed in a tempered martensite matrix, wherein
said compression ring is prepared from a steel wire having a composition consisting of by mass 1.00-1.10% of C, 0.50% or less of Si, 0.80-1.10% of Mn, and 0.20-0.60% of Cr, the balance being Fe and inevitable impurities, and wherein said steel wire is annealed at a temperature of 600-750° C. for 60-300 minutes.

Assignees

• Shima Yuji
• KAMON Ryouichi
• Kk Riken

Inventors

• Shima Yuji
• KAMON Ryouichi

Classifications

• C22C38/001 Primary

  containing N · CPC title

• C21D1/32

  Soft annealing, e.g. spheroidising · CPC title

• C22C38/20

  with copper · CPC title

• C21D6/002

  containing Cr (C21D6/004 takes precedence) · CPC title

• C22C38/58

  with more than 1.5% by weight of manganese · CPC title