Brass and Aluminium Fasteners | For Electrical, Light-Duty and Decorative Joints
In the legacy material table, brass and aluminium occupy the 'electrical and light-duty decorative' row — they sit outside the 8.8 / 10.9 / 12.9 property-class system, so selection is driven by conductivity, density, corrosion behaviour and appearance rather than tensile strength. Brass serves terminals, instruments and decorative hardware; aluminium serves weight-critical structures and panel parts. Two cautions: aluminium or brass against steel creates a galvanic couple, and these non-classed parts carry no metric property mark, so the order must state material and standard, not just the thread size.
Properties & Specifications
| Materials | Brass (Cu-Zn) · Aluminium alloys |
| Property Class | Not part of the ISO 898 metric class system — no 8.8 / 10.9 / 12.9 marking |
| Selection Basis | Conductivity, weight, appearance and corrosion behaviour rather than tensile strength |
| Typical Head Types | Slotted, pan, truss and cheese heads for panels and electrical parts |
| Galvanic Note | Coupling with steel or stainless accelerates attack on the less noble part; insulating washers are advised |
| Service Temperature | Set by the base alloy and any insulating parts; confirm with the design |
| Strength Ceiling | Far below class 8.8 — never for structural or vibrating load paths |
| Relative Cost | Material-driven; usually above mild-steel equivalents of the same size |
Material Advantages
Good conductivity: brass remains the traditional choice for terminals and conductive joints with stable contact resistance
Low density: aluminium suits weight-sensitive structures and portable equipment
Atmospheric corrosion resistance and appearance: colour is retained without plating, which is why panels and decorative hardware use it
Excellent machinability and cold-forming, allowing thin heads and wide bearing faces that are hard to form in carbon steel
More manageable galvanic behaviour when mated with aluminium profiles and zinc die-castings, avoiding large potential differences
Applications
Terminals, switches and instrument enclosures
Copper-bar joints in distribution boards and cabinets
Decorative hardware, door furniture and fittings
Panel screws and light-duty joints into plastic and thin sheet
Weight-critical equipment structures mated to aluminium profiles
Never for: structural load paths, vibration, alternating load or safety parts
Grade Selection
| Class / Grade | Service temperature | Notes |
|---|---|---|
| Brass | —（旧站未给出） | The electrical and decorative workhorse; conductive, outside the strength-class system |
| Aluminium | —（旧站未给出） | Lightweight structural parts; mind galvanic attack against steel |
| Steel 4.8 | ≤ 80°C（电镀锌） | The safer route when light-duty parts still need a class mark |
| A2-70（304） | 含氯水 > 60°C 有风险 | The alternative when appearance, corrosion resistance and a property class are all required |
Frequently Asked Questions
No. They carry no 8.8 / 10.9 / 12.9 marking and sit outside that system, so an order reading simply 'M6 brass bolt' is ambiguous. Always state the alloy grade and the governing standard, and for load-bearing work switch to a carbon-steel or stainless class part.
Not directly outdoors. Aluminium is less noble than steel, so in damp service a galvanic couple forms with galvanised or bare steel and the aluminium corrodes faster. Where weight matters, isolate with insulating washers, or specify class 8.8 carbon steel with a Delta-Tone coating.
Conductive joints are judged by contact resistance and its stability, and brass holds up better than plated carbon steel, which can rust and push contact resistance up. Do watch the copper-to-aluminium busbar interface and use the code-compliant transition connector.
Get Grade Selection & Quotation
Submit your duty parameters (temperature, pressure, media, speed) — engineers reply with grade selection and quotation within 24 hours.