JIS 7075 Bar & Rod - AFNOR 7075A-Z5GU Rods & Round Bars

Product Description

When cross-referencing global supply routes or dealing with historical technical drawings, you will frequently run into the Japanese JIS H4100 / H4040 standards and the French AFNOR NF A50-411 standards for 7075 aluminum.

While they all target the exact same base $Al-Zn-Mg-Cu$ metallurgical profile, their designation systems, processing controls, and specific mechanical testing requirements have unique nuances.

1. Nomenclature & Standards Mapping

The French AFNOR designation explicitly lists the critical alloying elements, whereas the Japanese JIS standard adopts the traditional 4-digit international system.

• Japanese System: JIS A7075 (governed by JIS H4040 for extruded bars, rods, and wires, and JIS H4100 for extruded shapes).

• French System: AFNOR 7075 / A-Z5GU (often specified in aerospace legacies as A-Z5GU-T6 or A-Z5GU-T73).

2. Chemical Composition Nuances

While globally unified under the Aluminum Association registry, minor tolerance windows can shift slightly between regional master standards.

Note on Impurities: French aerospace specifications for A-Z5GU often impose tighter restrictions on Iron ($Fe \le 0.40\%$) and Silicon ($Si \le 0.30\%$) than generic global standards to maximize fracture toughness and fatigue resistance in high-stress structural components.

3. Temper Comparison & Mechanical Testing Variations

The mechanical properties are tested using slightly different sample geometries depending on the standard system, resulting in variations in specified minimum elongation values.

Peak Strength Temper: JIS T6 vs. AFNOR T6 / T6511

• JIS A7075-T6: Typically requires a minimum Yield Strength ($R_{p0.2}$) of 470 to 480 MPa and Ultimate Tensile Strength ($R_m$) of 540 to 550 MPa depending on the diameter of the bar. Elongation values are calculated using a gauge length based on $5D$ ($5 \times \text{diameter}$).

• AFNOR A-Z5GU-T6511: Controlled stretching (the "511" suffix) is strictly utilized to relieve residual quenching stresses before machining. Mechanical limits align with European EN 755-2, matching or slightly exceeding a minimum $R_m$ of 540 MPa.

Stress Corrosion Resistant Temper: JIS T73 vs. AFNOR T73 / T7351

• Utilized when the component operates under sustained tensile stress in corrosive environments to prevent premature micro-cracking. Yield strength drops to roughly 380 - 400 MPa, but the risk of catastrophic stress corrosion failure is eliminated.

4. Key Factors for Procurement and Manufacturing

• Machining Behavior: Both variants turn beautifully on a lathe or mill. Because 7075 is highly brittle compared to soft 6000-series alloys, it breaks chips cleanly, allowing for high feed rates without bird-nesting around the tooling.

• Certification Cross-Over: If you are substituting a JIS A7075 bar for an older AFNOR A-Z5GU drawing requirement, you must verify if the drawing requires an aerospace-level inspection schedule (such as EN 10204 3.1 or 3.2 traceability). Commercial-grade JIS bars may lack the micro-cleanliness testing required by European aerospace engineering specifications.