FASTENER TIPS: TESTING, TEST REPORTS, SUPPLIER OVERSIGHT

FASTENER TIPS: TESTING, TEST REPORTS, SUPPLIER OVERSIGHT Approved for Public Release

Topics • Past Problems • Quality Control • Test Methods • Test Variables • Test Report Content Fastener Testing Approved for Public Release

Past Problems • 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 Approved for Public Release

Piercing Diameter Minor Diameter Out of Tolerance Minor Diameter Within Tolerance Fastener Testing Approved for Public Release

Concentricity Socket is not centered in the head of the screw Socket is not centered in the head of the screw Head and shank are not concentric Fastener Testing Approved for Public Release

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 Approved for Public Release

Test Methods ASTM F606 Standard Testing Methods Are Typically Invoked Unless Otherwise Specified • Tensile / Yield / Elongation (Mach. specimens) • Axial Tension (Full Size fasteners) • Proof load (Full Size fasteners) • Wedge tension (Full Size fasteners) • Hardness Fastener Testing Approved for Public Release

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 Approved for Public Release

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 Approved for Public Release

Test Methods Gage Lengths Are Different For Ferrous And Non-ferrous Fasteners Fastener Testing Approved for Public Release

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 Approved for Public Release

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 Fastener Testing Approved for Public Release

Test Methods Determining sample size and test requirements FF-S-86 Fastener Testing Approved for Public Release

Test Methods Determining sample size and test requirements Mil-S-1222 Fastener Testing Approved for Public Release

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 Approved for Public Release

Test Reports • 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. Fastener Testing Approved for Public Release

Test ReportsC of C Fastener Testing Approved for Public Release

Test ReportsChemicals Fastener Testing Approved for Public Release

Test ReportsMechanicals Fastener Testing Approved for Public Release

Test ReportsNDT Fastener Testing Approved for Public Release

Summary • Past Problems • Quality Control • Test Methods • Test Variables • Test Report Content Fastener Testing Approved for Public Release

FASTENER TIPS: TESTING, TEST REPORTS, SUPPLIER OVERSIGHT