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BS ISO 6621-4:2024 Internal combustion engines. Piston rings - General specifications, 2024
- undefined
- Foreword
- Introduction
- 1 Scope
- 2 Normative references
- 3 Terms and definitions
- 4 Piston ring codes
- 5 Designation of piston rings [Go to Page]
- 5.1 Designation elements and order [Go to Page]
- 5.1.1 General
- 5.1.2 Mandatory elements
- 5.1.3 Measurement principles
- 5.1.4 Additional elements
- 5.1.5 Elements for additional marking
- 5.2 Designation examples [Go to Page]
- 5.2.1 Designation example of a piston ring in accordance with ISO 6622-1
- 5.2.2 Designation example of a piston ring in accordance with ISO 6624-1
- 5.2.3 Designation example of a piston ring in accordance with ISO 6626-1
- 6 Designation of piston rings [Go to Page]
- 6.1 General
- 6.2 Mandatory topside identification marking
- 6.3 Additional marking
- 7 General characteristics [Go to Page]
- 7.1 Ring shape
- 7.2 Light tightness
- 7.3 Closed gap
- 7.4 Tangential force, Ft, and diametral force, Fd, of single piece piston rings [Go to Page]
- 7.4.1 Calculation of Ft, and Fd values in dimension tables of dimensional standards
- 7.4.2 Correction of Ft, and Fd values
- 7.4.3 Examples for correction of Ft and Fd
- 7.5 Tangential force Ft of multipiece oil control rings as specified in ISO 6626-1, ISO 6626-2, and ISO 6626-3 [Go to Page]
- 7.5.1 General
- 7.5.2 Rounding of values
- 7.5.3 Examples for calculating tangential force Ft
- 7.6 Tangential force Ft of expander/rail oil control rings as specified in ISO 6627 [Go to Page]
- 7.6.1 General
- 7.6.2 Example for calculating the tangential force Ft — Selected type of piston ring: ISO 6627 –ES3 – 85 × 3 – MC67 MC68/CR1 PNH
- 8 Notches for preventing ring rotation [Go to Page]
- 8.1 Ring joint with internal notch (only for compression rings as specified in ISO 6622 and ISO 6624)
- 8.2 Ring joint with side notch (only for compression rings as specified in ISO 6622)
- 9 Machining of surfaces [Go to Page]
- 9.1 Peripheral surfaces
- 9.2 Side faces
- 9.3 Other surfaces
- 10 Plated, coated, and treated surfaces [Go to Page]
- 10.1 Chromium plating on peripheral and side surfaces [Go to Page]
- 10.1.1 General
- 10.1.2 Chromium plating thickness
- 10.1.3 Chromium plated rings of fully faced design
- 10.1.4 Chromium plated rings of semi-inlaid design
- 10.1.5 Chromium plated rings of inlaid design
- 10.1.6 Side Chromium plated rings design
- 10.1.7 Radius, chamfer and dimensions of peripheral edges of chromium plated rings
- 10.1.8 Peripheral edges at the gap of chromium plated rings and rails
- 10.1.9 Hardness of chromium plating
- 10.2 Spray-coated peripheral surfaces [Go to Page]
- 10.2.1 Codes
- 10.2.2 Spray-coating thickness
- 10.2.3 Spray-coated rings of fully faced design
- 10.2.4 Spray-coated rings of semi-inlaid design
- 10.2.5 Spray-coated rings of inlaid design
- 10.2.6 Radius, chamfer of peripheral edges of spray-coated rings
- 10.2.7 Peripheral edges at gap of spray-coated rings
- 10.2.8 Hardness of spray-coating
- 10.3 Nitride surfaces [Go to Page]
- 10.3.1 Codes
- 10.3.2 Nitride case depth
- 10.3.3 Radius and dimensions of outside and inside edges of nitride steel rings
- 10.3.4 Peripheral edges at the gap of nitride steel rings and rails
- 10.4 Treated surfaces [Go to Page]
- 10.4.1 Ferro-oxidized all over — Code FE — Coating thickness (0,001 to 0,005) mm
- 10.4.2 Phosphated all over — Code PO — Coating thickness 0,002 mm min.
- 10.4.3 Phosphated all over — Code PR — Coating thickness 0,002 mm max.
- 10.5 Physical vapour deposition coating (PVD) [Go to Page]
- 10.5.1 Codes
- 10.5.2 PVD coating
- 10.5.3 PVD coating thickness
- 10.5.4 Hardness of PVD coating
- 10.5.5 Peripheral edges at the gap of PVD-coated rings and rails
- 11 Miscellaneous [Go to Page]
- 11.1 Cleanliness
- 11.2 Corrosion protection
- 11.3 Packaging
- 12 Traceability (optional)
- Bibliography [Go to Page]
