FASTENER TIPS: TESTING,
TEST REPORTS, SUPPLIER
OVERSIGHT
Approved for Public Release
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Topics
• Past Problems
• Quality Control
• Test Methods
• Test Variables
• Test Report Content
Fastener Testing
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Past Problems
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Lack of hydrogen embrittlement relief
Wrong wedge angles
Wrong gage lengths
Sampling
Process control of piercing diameter
Concentricity of head and/or socket to
shank
Fastener Testing
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Piercing Diameter
Minor Diameter
Out of Tolerance
Minor Diameter
Within Tolerance
Fastener Testing
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Concentricity
Socket is not centered in
the head of the screw
Head and shank are
not concentric
Fastener Testing
Socket is not centered in
the head of the screw
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Topics
• Past Problems
• Quality Control
• Test Methods
• Test Variables
• Test Report Content
Fastener Testing
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Quality Control
Mil-I-45208 “Inspection System Requirement”
Requires:
•Clear and concise procedures. (Para. 3.2.1)
•Use of calibrated equipment. (Para. 3.3)
•Providing and maintaining adequate records (i.e. Objective Quality
Evidence (OQE)). (Para. 3.2.2)
Other quality standards may apply ,however the rules are
basically the same (e.g. MIL-Q-9858, ISO 9001).
Fastener Testing
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Topics
• Past Problems
• Quality Control
• Test Methods
• Test Variables
• Test Report Content
Fastener Testing
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Test Methods
ASTM F606 Standard Testing Methods Are
Typically Invoked
Unless Otherwise Specified
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Tensile / Yield / Elongation (Mach. specimens)
Axial Tension (Full Size fasteners)
Proof load (Full Size fasteners)
Wedge tension (Full Size fasteners)
Hardness
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Test Methods
Flat surface
Cylindrical
surface
• Hardness testing performed on a
convex cylindrical surface
• Correction factors of ASTM E18
need to be applied
Fastener Testing
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Test Methods
Determination Of Proper Wedge Angle For
Wedge Testing
• ASTM F606 (Unless otherwise specified)
• ASTM A574 (Socket Head Cap Screws)
• MIL-S-1222H3 (Titanium, SC 10-122)
Fastener Testing
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Test Methods
Gage Lengths Are Different For Ferrous And Nonferrous Fasteners
Fastener Testing
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Test Methods
Plated Steel Fasteners May Require Additional
Processing And Testing
• The plating process can cause Hydrogen Embrittlement
of steel fasteners.
• Post plate baking is normally required to drive off
hydrogen introduced into the base material
• Hydrogen Embrittlement can cause delayed cracking.
• Stress Durability Testing may be required to determine
the effectiveness of the post plate baking process.
Fastener Testing
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Test Methods
Determining Sample Size And Test
Requirements
• The manufactured lot size is needed
to determine the correct number of
samples.
• Type of specimens.
– Machined specimens
– Full size fasteners
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Test Methods
Determining sample size and test requirements
FF-S-86
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Test Methods
Determining sample size and test requirements
FF-S-86
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Test Methods
Determining sample size and test requirements
Mil-S-1222
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Test Methods
Determining sample size and test requirements
Mil-S-1222
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Topics
• Past Problems
• Quality Control
• Test Methods
• Test Variables
• Test Report Content
Fastener Testing
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Test Variables
Variables that can affect test results
• Fixturing, Alignment.
• Speed of applied load.
• Test Specimen preparation (Surface
finish).
• Tool marks act as stress risers.
Fastener Testing
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Topics
• Past Problems
• Quality Control
• Test Methods
• Test Variables
• Test Report Content
Fastener Testing
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Test Reports
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Name of Testing Organization
Date of the test
Purchase Order number and Item number
Manufactured lot size
Material Spec. Alloy, Type, Class, Grade, Condition
Type of specimen tested (machined vs. full size)
Traceability to hardware (Lot Code)
Acceptance criteria.
Statement of acceptance or rejection
Units should be the same as those contained in the
acceptance spec. (lbs vs. psi)
• Signature of test organization representative and date.
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Test Reports
C of C
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Test Reports
Chemicals
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Test Reports
Mechanicals
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Test Reports
Mechanicals
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Test Reports
Mechanicals
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Test Reports
NDT
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Test Reports
NDT
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Summary
• Past Problems
• Quality Control
• Test Methods
• Test Variables
• Test Report Content
Fastener Testing
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