Testing Standards and Quality Assurance for Aircraft Grade Aluminum 7175 Sheet

In the aerospace industry, the demand for materials that combine high strength, lightweight structure, and absolute reliability is critical. Among the most trusted alloys in this category is Aircraft Grade Aluminum 7175 Sheet — a high-performance aluminum-zinc-magnesium-copper alloy engineered to perform under extreme stress and fatigue conditions.

However, what truly ensures its reliability in flight-critical components is not only the alloy’s composition but also its testing standards and quality assurance systems. From melting to final inspection, each production step must comply with rigorous international standards to guarantee consistent strength, toughness, and corrosion resistance.

This article provides a comprehensive overview of the testing standards and quality assurance practices applied to Aircraft Grade Aluminum 7175 Sheets at SASAALUMINUM, ensuring that every product delivered meets the demanding requirements of the aerospace sector.

Overview of Aircraft Grade Aluminum 7175

Aluminum Alloy 7175 is a high-strength 7xxx series aluminum alloy, similar to 7075 but optimized for improved fracture toughness and stress-corrosion resistance. It is primarily used in structural aircraft parts, where reliability and fatigue life are non-negotiable.

Typical Chemical Composition (%):

  • Zinc (Zn): 5.6 – 6.1

  • Magnesium (Mg): 2.0 – 2.5

  • Copper (Cu): 1.2 – 1.6

  • Chromium (Cr): 0.18 – 0.25

  • Aluminum (Al): Balance

Key Properties:

  • Very high tensile and yield strength

  • Excellent fatigue and stress-corrosion resistance (especially in T73/T74 tempers)

  • Good machinability and anodizing response

  • Consistent performance in both ambient and elevated temperatures

At SASAALUMINUM, each 7175 sheet is processed through advanced melting, rolling, and heat treatment facilities, followed by extensive testing and inspection to ensure it meets international aerospace standards.

Importance of Testing and Quality Assurance

Aircraft-grade materials must meet exact specifications because even minor deviations can affect flight safety. Therefore, testing and quality assurance serve several key purposes:

  1. Verify Mechanical Integrity: Confirm tensile strength, hardness, and fatigue resistance.

  2. Ensure Chemical Accuracy: Validate that alloying elements are within standard limits.

  3. Detect Surface or Internal Defects: Identify cracks, inclusions, or segregation before machining.

  4. Maintain Dimensional Precision: Guarantee sheet thickness and flatness within tolerance.

  5. Ensure Traceability: Provide documentation for every stage of production.

SASAALUMINUM follows a zero-compromise policy on quality, ensuring that every Aircraft Grade Aluminum 7175 Sheet leaving the plant adheres to international standards such as ASTM, AMS, ISO, and EN.

International Standards for Aluminum 7175 Testing

The production and certification of Aircraft Grade Aluminum 7175 Sheets are governed by strict global standards, including:

Standard Scope
ASTM B209 Aluminum and aluminum-alloy sheet and plate specifications
AMS 4058 / AMS 4078 Aerospace material specifications for Aluminum 7175-T6/T73
EN 485-2 Mechanical properties of wrought aluminum alloys
ISO 6892-1 Tensile testing of metallic materials
EN 10204 3.1 / 3.2 Material test certificate and traceability requirements

SASAALUMINUM ensures that all production batches are fully traceable, with test certificates conforming to EN 10204 3.1 or 3.2 provided to customers.

Key Testing Categories for Aircraft Grade Aluminum 7175 Sheet

Testing of 7175 aluminum sheets covers mechanical, chemical, non-destructive, and metallurgical evaluations to ensure compliance and performance consistency.

1. Mechanical Testing

Mechanical tests determine the material’s strength, ductility, and toughness under various conditions.

a. Tensile Test (ASTM E8 / ISO 6892-1)

  • Measures yield strength, ultimate tensile strength, and elongation.

  • Conducted at room and elevated temperatures to simulate operational conditions.

Typical Results for 7175-T6 Sheet:

  • Ultimate Tensile Strength: 570–600 MPa

  • Yield Strength (0.2%): 480–520 MPa

  • Elongation: 10–12%

b. Hardness Test (ASTM E18)

  • Confirms proper heat treatment and aging.

  • Typical hardness: 150–160 HB for T6 condition, 140–145 HB for T73.

c. Fatigue and Fracture Testing (ASTM E466 / E1820)

  • Determines fatigue life under cyclic loads.

  • Measures fracture toughness (K_IC) and resistance to crack propagation.

These tests ensure that Aluminum 7175 can withstand repetitive stresses experienced during aircraft operation without premature failure.

2. Chemical Composition Analysis

Chemical testing verifies that the alloy’s elemental composition matches the defined specifications.

Testing Methods:

  • Optical Emission Spectroscopy (OES): For major elements such as Zn, Mg, Cu, Cr.

  • Inductively Coupled Plasma (ICP) Analysis: For trace elements.

  • Combustion Analysis: For carbon, hydrogen, and oxygen.

These tests are performed on each batch to maintain compositional uniformity, ensuring predictable mechanical behavior during heat treatment and machining.

3. Non-Destructive Testing (NDT)

To detect defects without damaging the material, SASAALUMINUM employs advanced NDT techniques.

a. Ultrasonic Testing (UT) – ASTM B594

  • Detects internal discontinuities, voids, and inclusions.

  • Conducted using automated immersion systems for full sheet scanning.

b. Eddy Current Testing (ECT) – ASTM E309

  • Identifies surface or near-surface cracks and inclusions.

  • Used for thin sheets or post-machining inspection.

c. Visual and Dimensional Inspection – ASTM B918

  • Checks for surface defects, scratches, and warping.

  • Verifies sheet flatness, thickness uniformity, and edge straightness.

Each Aluminum 7175 sheet at SASAALUMINUM undergoes 100% ultrasonic inspection, ensuring it is free from internal flaws before certification.

4. Metallographic Examination

Metallographic testing analyzes the alloy’s microstructure to verify proper grain refinement and precipitate distribution.

Tests Include:

  • Grain Size Measurement (ASTM E112): Ensures uniform fine-grain structure.

  • Phase Identification: Confirms presence of strengthening phases (MgZn₂).

  • Precipitate Distribution Analysis: Evaluates heat treatment uniformity.

This microscopic evaluation ensures that the heat treatment has produced the desired mechanical properties and that no unwanted secondary phases (like η or S phase) have formed.

5. Corrosion and Environmental Testing

Aluminum 7175 must resist corrosion under harsh environmental conditions such as humidity, salt, and exhaust gases.

a. Salt Spray Test (ASTM B117):

  • Simulates marine exposure to verify coating and anodizing performance.

b. Intergranular Corrosion Test (ASTM G110 / ASTM G34):

  • Checks susceptibility to grain boundary attack after heat treatment.

c. Stress Corrosion Cracking (ASTM G47):

  • Determines resistance under tensile stress in corrosive environments.

These tests are crucial for aircraft structures operating in coastal or high-humidity regions.

6. Dimensional and Surface Quality Testing

Aircraft-grade aluminum sheets must meet strict tolerances for thickness, flatness, and surface finish.

Dimensional Testing:

  • Conducted using laser-based systems and coordinate measuring machines (CMM).

  • Typical tolerances: ±0.05 mm for thickness, ≤0.5 mm/m for flatness.

Surface Roughness Testing (ISO 4287):

  • Evaluates finish quality post-rolling or machining.

  • Typical Ra value ≤ 0.8 µm for aerospace-grade sheets.

These precision checks ensure compatibility with downstream operations such as riveting, bonding, or forming.

Quality Assurance Process at SASAALUMINUM

At SASAALUMINUM, quality assurance (QA) is integrated into every phase of production — from raw material procurement to final inspection and packaging.

1. Raw Material Verification

  • Incoming aluminum and alloying elements are verified using spectrographic analysis.

2. In-Process Quality Monitoring

  • Automated sensors track rolling temperature, reduction ratio, and surface condition.

3. Post-Processing Control

  • Heat treatment furnaces calibrated to ±2°C for consistent microstructure.

  • Aging cycles logged and traceable through digital systems.

4. Final Inspection

  • Each Aluminum 7175 sheet is inspected visually and dimensionally.

  • Certified technicians perform ultrasonic and hardness testing before marking.

5. Certification and Traceability

  • Each batch includes full MTC (Material Test Certificate) with mechanical, chemical, and NDT data.

  • Documents are traceable to individual production lots, ensuring transparency for aerospace clients.

Compliance and Certifications

SASAALUMINUM operates under internationally recognized quality management systems, ensuring full compliance and global customer trust.

Certifications Include:

  • ISO 9001:2015 – Quality Management System

  • AS9100 – Aerospace Industry Standard

  • PED 2014/68/EU – Pressure Equipment Directive Compliance

  • NADCAP (In Process) for heat treatment and testing validation

These certifications reinforce SASAALUMINUM’s position as a reliable supplier for aviation, defense, and engineering industries.

Applications of Tested and Certified Aluminum 7175 Sheets

Due to its high strength and verified reliability, SASAALUMINUM 7175 Sheets are widely used in:

  • Aircraft Structures: Wing spars, fuselage skins, and bulkheads.

  • Landing Gear Components: High-stress parts requiring toughness and fatigue resistance.

  • Defense Systems: Armored structures and missile components.

  • Aerospace Tooling: Jigs, fixtures, and precision molds.

In all these applications, certified testing ensures consistent mechanical integrity and long-term reliability.

Why Choose SASAALUMINUM

SASAALUMINUM is dedicated to producing premium-grade Aircraft Aluminum 7175 Sheets that meet the highest international testing and quality standards.

Our Advantages:

  • Comprehensive Testing: In-house mechanical, chemical, and NDT facilities.

  • Precision Equipment: Computer-controlled heat treatment and rolling lines.

  • Global Compliance: Conformance with ASTM, AMS, and EN standards.

  • Full Traceability: EN 10204 3.1/3.2 documentation for every order.

  • Technical Support: Expert metallurgists and aerospace engineers available for consultation.

Through continuous innovation and stringent quality control, SASAALUMINUM ensures that every sheet delivers performance, precision, and trust.

Conclusion

The performance and reliability of Aircraft Grade Aluminum 7175 Sheet depend not only on alloy composition but also on comprehensive testing and quality assurance. Through advanced inspection, international standard compliance, and meticulous process control, SASAALUMINUM guarantees unmatched quality for critical aerospace and defense applications.

By maintaining rigorous testing protocols and global certifications, SASAALUMINUM stands as a trusted partner for manufacturers seeking precision-engineered, high-strength aluminum materials that meet the most demanding aviation standards.

Post time: Nov-04-2025