Summary of test:
ASTM F606 is performed by fastener manufacturers and commercial and government laboratories serving the construction industry.
Why is it done?
One type of grip for testing structural bolts
Fastener manufacturers are required to test the products they sell to ensure that the specification cited is met. Significant liabilities can result from providing non-compliant product. Proof testing and tensile testing to failure
are two of the most common methods employed. These often include the use of bolt extensometers and angled wedge washers to meet ASTM F606 requirements.
Users of fasteners often require that the fasteners they receive be tested by independent sources prior to acceptance. There have been issues with unauthorized substitution of grades and materials and foreign sources not meeting the intended specification. Testing helps to minimize the possible installation of inferior quality fasteners.
Why is it important?
The strength of bolted joints is a fundamental requirement in the design and construction of buildings, bridges, pipe lines, and chemical and petroleum processing plants. The failure of a single fastener may result in release of toxic or flammable fluids or gases into the atmosphere or potable water systems, possibly resulting in a fire or explosion. Structural failures can result in sagging or even collapse of bridges and buildings.
What ADMET equipment is needed?
- an ExPress servo hydraulic testing machine of capacities 20,000 to 300,000 LBF depending upon fastener size and specification, or
- an ADMET retrofit/upgrade of an existing tensile testing machine to automatic servo control are both available. The upgrade/retrofit is performed at the customer’s site including training on how to make use of the fastener fixtures and operate the testing system.
- Fastener fixtures including holders, washers, wedges and bolt extensometer are among the tools ADMET offers for the testing of threaded fasteners.
Changes in the force rate can affect the yield strength, tensile strength and elongation values, especially for materials which are highly strain rate sensitive. In general, the yield strength and tensile strength will increase with increasing strain rate. Elongation values generally decrease as the strain rate increases.
Fastener testing using manually operated machines places a burden on the technician performing the test. The rate of testing is deliberately slow and thus the length of time to test can be long. All the while the operator is expected to be monitoring and adjusting the controls of the machine to ensure there is consistent force application at the specified rate. This is often not the case and inconsistent force application from test to test results. Undesirable scatter in the test data occurs and sometimes good product gets rejected while at other times out of spec product can be seen as acceptable. Automatic control minimizes this scatter and provides inherent documentation of the testing force application.
ADMET systems with automatic servo controls eliminate these unpredictable variables which can crop up during testing. To learn more about ADMET’s products, email sales@admet.com or call (800) 667-3220.
