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SAE J1467-2018: Material and Dimensional Standards for Steel Clip Fastener Fittings
This standard describes material and dimensional requirements for steel clip fastener fittings used in hydraulic systems on industrial equipment, particularly in mining applications. The fittings consist of male and female bodies, O-rings, back-up rings, and staples (clips). This article highlights key specifications, design considerations, and common pitfalls to help engineers select and apply these components effectively.
Scope and Purpose
SAE J1467 was stabilized in 2018 and covers products that are mature and unlikely to change. The standard ensures that clip fastener fittings meet minimum strength, corrosion resistance, and dimensional interchangeability requirements. These fittings are primarily used in mining and other heavy industrial hydraulic systems.
Material and Construction Requirements
Male and Female Bodies: The standard specifies steel such as AISI 12L14, 1137, 1141 or other free-cutting steels with a minimum yield strength of 193 MPa and minimum tensile strength of 345 MPa. Parts may be forged, cold headed, or machined, and multiple components can be bonded by brazing or welding.
O-Rings and Back-Up Rings: O-rings must be compatible with the conveyed fluid, with suitable materials including nitrile (NBR) or fluoroelastomers (FKM) with a minimum Shore A hardness of 80. Back-up rings should be made from acetal homopolymer, polyamide, or PTFE. Surface imperfections must meet ISO 3601-3 limits.
Staples (Clips): The staple must be manufactured from corrosion-resistant steel or spring steel. Contour and details are optional as long as interchangeability is maintained and full pressure capability is preserved.
⚠️ Critical Requirement: Cadmium plating is prohibited. Hexavalent chromate coatings are not preferred. All carbon steel parts must pass a 72-hour salt spray test per ASTM B117 or ISO 9227 without red rust, except in specified areas.
Dimensional Specifications and Interchangeability
Fitting sizes are designated by the nominal inside diameter of the hose, with metric sizes ranging from 6.3 to 51 (corresponding to SAE dash sizes -4 to -32). The standard provides detailed dimensional tables for female and male bodies, O-rings, back-up rings, and clips. Concentricity tolerances are critical: for female bodies, d2 and d3 must be concentric within 0.05 mm TIR; for male bodies, diameters within the specified length must be concentric within 0.13 mm TIR, except diameter A which requires 0.05 mm TIR.
| Metric Size | SAE Dash Size (Ref) |
|---|---|
| 6.3 | -4 |
| 10 | -6 |
| 12.5 | -8 |
| 19 | -12 |
| 25 | -16 |
| 31.5 | -20 |
| 38 | -24 |
| 51 | -32 |
🛠️ Design Insight: Interchangeability of male and female parts is a core requirement. The staple design must not compromise the assembly’s pressure rating. Ensure material and dimensional compliance to maintain full working pressure.
Pressure Ratings and Workmanship
The standard defines maximum working pressures and minimum burst pressures for each size. For example, a 6.3 mm size has a maximum working pressure of 45 MPa and a minimum burst of 180 MPa. Proper workmanship requires fittings to be free from contaminants, burrs, scale, slivers, and other defects. Sealing surfaces and threads must be protected from damage during handling and shipping.
| Metric Size | Dash Size | Max Working Pressure (MPa) | Min Burst Pressure (MPa) |
|---|---|---|---|
| 6.3 | -4 | 45 | 180 |
| 10 | -6 | 40 | 160 |
| 12.5 | -8 | 35 | 140 |
| 19 | -12 | 27.5 | 110 |
| 25 | -16 | 27.5 | 110 |
| 31.5 | -20 | 21 | 84 |
| 38 | -24 | 21 | 84 |
| 51 | -32 | 17.5 | 70 |
Internal fluid passages must be protected from corrosion during storage and shipping. Changes in plating or coating must be re-qualified to ensure assembly torque is not affected.
Frequently Asked Questions
What steel grades are acceptable for male and female components?
The standard recommends AISI 12L14, 1137, 1141, or other free-cutting steels with minimum yield strength of 193 MPa and minimum tensile strength of 345 MPa.
What are the corrosion protection requirements?
All carbon steel parts must be plated or coated to pass a 72-hour salt spray test (ASTM B117 or ISO 9227) without red rust, except on internal passages, edges, and post-forming areas. Cadmium plating is prohibited.
What O-ring materials and hardness are specified?
O-rings should be nitrile (NBR) or fluoroelastomer (FKM) with a minimum Shore A hardness of 80. They must be compatible with the fluid being conveyed.
Why is interchangeability important in clip fastener designs?
Interchangeability ensures that male and female parts from different production runs or manufacturers can be reliably mated without reducing the assembly’s pressure capability. The standard mandates that the staple design must not affect interchangeability.
