7050 (AMS 4050M, ASTM B247) large diameter pipes feature copper-zinc-magnesium alloying system optimized for high-strength structural applications:

Alloy Chemistry:

Zinc (Zn): 5.7-6.7% (primary strengthening)

Magnesium (Mg): 1.9-2.6% (precipitation hardening)

Copper (Cu): 2.0-2.6% (stress corrosion resistance)

Trace Elements:

Zirconium (Zr): 0.08-0.15% (grain refinement)

Iron (Fe): ≤0.15% max

Silicon (Si): ≤0.12% max

Manganese (Mn): ≤0.10% max

Advanced Manufacturing Process:

Billet Pre-heating: 430-480°C (Argon atmosphere)

Hot Extrusion: 315-410°C at 100-350 MN press force

Cold Draw Sizing: 15-30% reduction

Stretch Straightening: 1-3% permanent elongation

Heat Treatment: T7451/T7651 proprietary aging

Calibration: 3-roll planetary sizing system

Surface Finish: Micro-peening (0.5-1.2μm Ra)

Certified to AMS-QQ-A-200/11 and EN 754 standards with full digital material traceability.

 

 

 

Property	T7451 Temper	T7651 Temper	Test Standard
Ultimate Tensile Strength	510-550 MPa	530-570 MPa	ASTM E8
Yield Strength (Rp0.2)	455-495 MPa	470-510 MPa	ASTM E8
Elongation (%)	9-12%	7-10%	ASTM E8
Fracture Toughness KIC	32 MPa√m	29 MPa√m	ASTM E399
Compression Yield	480-520 MPa	500-540 MPa	ASTM E9
Shear Strength	300-335 MPa	310-345 MPa	ASTM B565
Fatigue Strength (10⁷)	160-185 MPa	180-205 MPa	ASTM E466
Bearing Strength	840-890 MPa	860-910 MPa	ASTM E238

 

Maintains ≥90% mechanical properties at temperatures from -55°C to +125°C per ASTM E21.

 

Proprietary Aging Sequence:

Solution Treatment: 477°C ±5°C for 2-4 hours

Controlled Quenching: Polymer quench at 40-60°C/sec

Stress Relief: 3% stretch deformation

Aging Protocol:

T7451: 107°C/8hr + 163°C/30hr

T7651: 121°C/6hr + 177°C/20hr

Microstructural Characteristics:

Grain Size: ASTM 6-7 (25-40μm)

Precipitate Structure:

η’ (MgZn₂) phase: 10-30nm

Al₃Zr dispersoids: 5-15nm

Dislocation Density: 4-6×10¹⁰/cm²

Grain Boundary Structure: Discrete η-phase

Recrystallization: ≤15%

Texture Index: <1.5 random multiples

 

 

 

Parameter	Standard Range	Precision Tolerance	Special Capabilities
Outer Diameter	200-1200 mm	±0.15% OD	Up to 2500 mm
Wall Thickness	8-80 mm	+10%/-5% WT	3-150 mm available
Length	3-20 m	+10mm/-0mm	Up to 30m sections
Ovality	≤0.8%	≤0.3% (critical)	–
Straightness	1.0 mm/m	0.3 mm/m	–
Perpendicularity	≤0.5°	≤0.2°	–
Wall Uniformity	±7%	±3%	–

 

Advanced Forming Technologies:

Spin Forming for end configurations

Flow Turning for thickness variation

Explosive Expansion for size transitions

Mandrel Forging for flanged ends

Localized Solution Heat Treatment

 

Condition	Performance Rating	Key Metrics	Protection Methods
Salt Spray Exposure	Excellent	<0.002 mm/yr corrosion rate	Alodine 1200 treatment
Stress Corrosion Cracking	Good	Threshold >150 MPa	T7451 overaged temper
Galvanic Corrosion	Moderate	<0.003 mm/yr when isolated	Fiberglass isolation
Atmospheric Exposure	Excellent	0.0001 mm/yr rural environment	Chromate conversion coating
High Humidity	Good	No pitting after 3000hr	Anodizing (Type II)

 

Surface Enhancement Options:

Hard Anodizing (50-70μm, 500-600 HV)

Plasma Electrolytic Oxidation (PEO)

HVOF WC-Co Coating (1200-1400 HV)

Electroless Nickel Plating (ENP)

Thermal Spray Aluminum (TSA)

 

 

 

Operation	Tool Material	Recommended Parameters	Dimensional Precision
Deep Hole Drilling	Carbide gundrills	25-45 m/min, 0.05-0.12 mm/rev	±0.05 mm
End Milling	TiAlN coated carbide	250-400 m/min, 0.1-0.3 mm/tooth	Ra 0.8-1.6μm
Tapping	Coated HSS-E taps	8-15 m/min, spiral point	6H tolerance
Boring	CBN-tipped bars	150-250 m/min, 0.05 mm/rev	IT7 grade
Trepanning	PCD cutters	60-100 m/min	Wall runout ±0.1 mm

 

Machinability Advantages:

Chip Formation: Short breaking chips

Built-up Edge Tendency: Low (Class B per ISO 3685)

Cutting Force Requirements: 20-30% lower than steel

Residual Stress Control: Cryogenic machining capable

Typical Surface Finish: Ra 0.4-1.6 μm achievable

 

Optimal Welding Processes:

Variable Polarity PAW (VPPAW):

Current: 180-300A

Travel Speed: 100-250 mm/min

Filler: ER7037 (Al-Zn-Mg)

Friction Stir Welding:

Spindle Speed: 350-600 RPM

Traverse: 80-200 mm/min

Down Force: 12-20 kN

Specialized Joint Designs:

High-Strength Mechanical Joints:

Swaged collars with 1:15 taper

Interference fit bushings

Adhesive Bonding Systems:

Epoxy novolac: 25 MPa at 100°C

Polyurethane methacrylate: 18 MPa

Double-Welded Joints:

Root gap: 0.8-1.5mm

Groove angle: 60°±5°

Back-gouging: Full penetration

 

 

 

Property	Value	Structural Significance
Density	2.83 g/cm³	60% weight savings vs steel
Young’s Modulus	71 GPa	Stiffness-to-weight ratio
Poisson’s Ratio	0.33	Stress distribution
CTE (20-150°C)	23.6 μm/m·°C	Thermal compatibility
Thermal Conductivity	130 W/m·K	Heat dissipation
Electrical Resistivity	41.5 nΩ·m	Static discharge
Damping Capacity	0.002	Vibration reduction
Magnetic Permeability	1.00002	EMI protection

 

Rigorous Testing Protocols:

Ultrasonic Testing: 5-15 MHz probes, AWS D1.2 standards

Eddy Current Inspection: 1-3% sensitivity

Hydrostatic Testing: 1.5x design pressure

Fracture Toughness: ESIS TC24 protocol

Fatigue Testing: 10⁷ cycles minimum

Residual Stress Analysis: X-ray diffraction method

Comprehensive Certification:

NADCAP AC7108 Accreditation

ISO 9001/AS9100 Quality Systems

PED 2014/68/EU Compliance

DNV GL Type Approval

ABS Material Certification

MIL-DTL-45225 Inspection

 

 

 

 

Primary Application Sectors:

Aerospace structural frameworks

Missile launch tube systems

Industrial hydraulic cylinders

Energy sector gas injection pipes

Heavy machinery booms and arms

Marine propulsion shafting

High-pressure gas storage

Telescope structural components

Handling & Storage:

VCI coating with desiccant packs

Non-metallic end protectors

Wooden saddles in storage racks

Never-stack direct contact policy

ISO container transport systems