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SAE J2226: Specifications for Type B Barrel Faced Steel Rectangular Piston Rings
SAE J2226, now cancelled, specifies the essential dimensional features of Type B barrel faced steel rectangular piston rings for internal combustion engines. This standard covers rings up to 200 mm diameter and 4.5 mm width, including fully faced and inlaid coated rings. Tolerances are defined at a six sigma quality level, ensuring high reliability in engine applications.
Scope and Key Features
The standard applies to reciprocating internal combustion engines. Type B rings are barrel faced, which helps in oil control and sealing. Key features include inside rounded edges and precise dimensions for radial wall thickness, ring width, and closed gap.
Dimensional Specifications and Coating Options
Table 4 in the standard provides dimensions and forces for various nominal diameters and ring widths. Coating options include chromium and molybdenum, with specified thicknesses. The following table summarizes coating layer thicknesses from SAE J2226.
| Coating Type | Code | Minimum Thickness (mm) |
|---|---|---|
| Chromium | CRF | 0.005 |
| Chromium | CR1 | 0.05 |
| Chromium | CR2 | 0.1 |
| Chromium | CR3 | 0.15 (for d1 ≥ 50 mm) |
| Molybdenum | MO1 | 0.05 |
| Molybdenum | MO2 | 0.1 |
| Molybdenum | MO3 | 0.15 (for d1 ≥ 50 mm) |
| Molybdenum | MO4 | 0.20 (for d1 ≥ 50 mm) |
🛠️ Design Insight: The six sigma tolerance approach in SAE J2226 indicates a modern quality control mindset, targeting very low defect rates. Coating force correction factors are essential for maintaining consistent ring tension; these factors vary by coating type and diameter range. For example, CR2/MO1 factors range from 0.70 to 0.93 depending on diameter.
Why SAE J2226 Was Cancelled and What to Use Instead
SAE J2226 was cancelled in 2008 because its content is covered by ISO 6622-2. To avoid duplication and confusion, engineers should now refer to ISO 6622-2 for specifications on steel rectangular piston rings.
⚠️ Important: When specifying piston rings, use ISO 6622-2 instead of SAE J2226. The SAE Piston and Ring Standards Committee supports ISO in updating these standards.
Frequently Asked Questions
How do I select the correct ring dimensions from the tables?
Refer to Table 4 for the given nominal diameter and ring width. The table provides radial wall thickness, closed gap, tangential force (Ft), and diametral force (Fd) with their tolerances.
What are the coating options and their thickness requirements?
Coating options include chromium (CRF, CR1, CR2, CR3) and molybdenum (MO1, MO2, MO3, MO4) with minimum thicknesses ranging from 0.005 mm to 0.20 mm, as shown in the table above.
How are force correction factors applied for coated rings?
Force correction factors depend on the coating type and nominal diameter. For example, for CR2/MO1, factors decrease from 0.93 for 150-200 mm to 0.70 for 30-50 mm. Apply these factors to the base forces from Table 4.
Why was SAE J2226 cancelled, and what should be used instead?
SAE J2226 was cancelled because it is superseded by ISO 6622-2. Engineers should now reference ISO 6622-2 for steel rectangular ring specifications.
