ISO 6622-2:2013

Overview

ISO 6622-2:2013 defines the essential dimensional features and nominal sizes for rectangular piston rings made of steel used in reciprocating internal-combustion engines. It covers rings with nominal diameters from 30 mm to 160 mm and specifies four ring types - R (straight-faced), B (barrel-faced), BA (asymmetrical barrel-faced) for h ≥ 1.2 mm, and M (taper-faced). The standard includes designation examples, common features, coatings/nitriding options, and force-factor data relevant to piston-ring selection and manufacturing.

Key topics and technical requirements

• Ring types and geometry: Definitions and figures for Type R, B, BA and M with dimensional tables (width h, axial dimensions, gauge widths).
• Nominal diameter range: Rings from 30 mm up to 160 mm are covered.
• Surface finishes and treatments:
  • Chromium plating / spray coatings - thickness codes (e.g., CR1, CR2; CR2 = 0.100 mm min.) and guidance on fully faced vs. inlaid surfaces.
  • PVD coatings - thickness codes (e.g., PC001, PC003, PC006).
  • Nitriding - case depth codes (e.g., NT030, NT050, … NT130) with peripheral and side-face minimum depths.
• Edge and bevel details: Outside/inside rounding limits, internal bevel (IF/IFU) for ring twist types and tapered rings.
• Force factors and performance data: Tables provide tangential and diametral forces and dimensional/force relationships (used in sealing and friction calculations).
• Designation format: Standard naming convention examples (e.g., Piston ring ISO 6622-2 R - 60 × 1,2 - MC62/CR2).

Practical applications and who uses it

• Engine designers and OEMs use ISO 6622-2 to select appropriate rectangular steel piston rings for road-vehicle and other reciprocating engines, ensuring dimensional compatibility and intended sealing/force performance.
• Ring manufacturers rely on the standard for machining, heat treatment, surface coating/nitriding specifications, and part designation to meet customer requirements.
• Component suppliers and quality engineers use the dimensional tables and force factors for quality control, inspection, and specification of coatings (chromium, PVD) and nitriding depths.
• Aftermarket and repair services reference the standard when matching replacement rings by type, diameter, and surface treatment.

Related standards

• ISO 6622-1: Rectangular rings made of cast iron (same series).
• ISO 6621 series and other piston-ring standards (see ISO 6621-3 and ISO 6621-4 referenced in the introduction for complementary requirements).

Keywords: ISO 6622-2:2013, piston rings, rectangular rings, steel piston rings, internal combustion engines, ring types R B BA M, nitrided, chromium-plated, PVD coating, ring dimensions, force factors.