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Understanding SAE J528-2006: Seamless Copper Tube for Automotive and General Purposes
SAE J528-2006 specifies minimum requirements for soft annealed seamless copper tube intended for automotive and general fluid systems. The standard covers manufacturing, dimensions, material composition, mechanical properties, and testing methods. Although cancelled in June 2006, it remains a historical reference and is comparable to ASTM B75.
Scope, Manufacture, and Key Specifications
The standard applies to cold-drawn and annealed seamless copper tube. Tubes must be clean, smooth, round, and free from defects. The average grain size must be at least 0.040 mm. Materials include UNS C10200, C12000, C12200, and DPA copper (see Table 2 in original for composition). Mechanical properties require a minimum ultimate tensile strength of 205 MPa and yield strength of 62 MPa.
Table 1 below lists nominal sizes and tolerances for common tube diameters.
| Nominal OD (mm) | OD Tolerance (±mm) | Wall Thickness (mm) | Wall Tolerance (±mm) |
|---|---|---|---|
| 3.18 | 0.05 | 0.76 | 0.08 |
| 6.35 | 0.05 | 0.76 | 0.063 |
| 9.53 | 0.05 | 0.81 | 0.063 |
| 12.70 | 0.05 | 0.81 | 0.063 |
| 19.05 | 0.063 | 0.89 | 0.063 |
For complete specifications, refer to the original document.
Testing and Acceptance Criteria
Three main tests ensure product quality: expansion, hydrostatic, and embrittlement.
Expansion Test
A sample is expanded on a 60-degree tapered pin until the outside diameter increases by 40%. The tube must show no cracking or rupture visible to the unaided eye. This test verifies ductility for flaring and bending.
Hydrostatic Test
Tube must withstand internal pressure that produces a hoop stress of 40 MPa, calculated using the formula P = 2St / (D – 0.8t). The test pressure need not exceed 7 MPa unless specified. This confirms pressure integrity.
Embrittlement Test
This test is required only if specified by the purchaser. Specimens are heated in a hydrogen atmosphere at 850°C, quenched, and examined microscopically for grain boundary attack indicative of embrittlement.
🛠️ Engineering Design Insight: The 40% expansion requirement ensures tubes can survive moderate forming without failure. The hydrostatic test provides a consistent pressure rating for system design. The grain size minimum supports ductility and fatigue resistance. For current designs, verify material selections against ASTM B75 or SAE J463.
Current Status and Frequently Asked Questions
SAE J528 was cancelled in June 2006 due to lack of updates and committee expertise. The standard is superseded by ASTM B75 and SAE J463 for copper tube specifications.
⚠️ Important: Engineers should not use SAE J528 for new designs without verifying against current industry standards. It remains useful for legacy system reference.
Frequently Asked Questions
- Is SAE J528 still active? No, it was cancelled in 2006 and is no longer maintained.
- What materials are allowed under SAE J528? The standard lists C10200, C12000, C12200, and a DPA alloy. C12200 (DHP copper) is most commonly specified.
- How does the expansion test work? A tube sample is expanded 40% in diameter using a tapered pin; no cracks or rupture are permitted.
- What is the hydrostatic test pressure formula? P = 2St / (D – 0.8t), with S = 40 MPa (6000 psi). Maximum test pressure is 7 MPa (1000 psi) unless otherwise specified.
