ASTM A1061 | Metals | Multi-Wire Strand Testing
ASTM A1061 is a testing standard that describes the mechanical testing procedure for testing multi-wire steel strand. Strands are made out of two or more steel wires wound together in a helical form. The mechanical properties of the strand are determined by a test in which fracture of the specimen occurs in the free span between the grips of the testing machine.
Gripping the strand wire and measuring its elongation can be challenging. ADMET wedge grips with serrated v-jaws are often used for A1061 multi-wire steel strand testing. The yield strength and elongation measurements can be done using the same extensometer or two separate extensometers. For yield strength measurements, the required extensometer is Class B-1 Model 3542 extensometer. For elongation measurements, a Class D extensometer is sufficient as long as the gauge length is 24 in (600 mm).
Prior to conducting ASTM A1061, it is important to read the entire specification in the relevant ASTM publication.
ASTM A1061 | Metals | Multi-Wire Strand Testing
- Measure and record the specimen dimensions necessary to determine the cross sectional area at its smallest point. The original cross sectional area is used for all engineering stress calculations.
- Mark the gauge length with a center punch, scribe marks or draw with ink. The distance between the gauge marks after the specimen is broken is used to determine the percent elongation at break.
- Zero the testing machine without the specimen inserted in the grips. Install the specimen in the grips and apply an initial load of 10% of the required minimum breaking strength to the specimen.
- Attach a Class B1 axial extensometer to the specimen to measure the yield strength or a Class D extensometer having a minimum gauge length of 24 in. (600 mm) to measure elongation. Please note that the extensometer needs to be removed prior to specimen failure. ADMET MTESTQuattro software stops test and prompts the removal of the extensometer once the total strain data has been satisfactorily obtained.
- The speed of testing is generally specified in one of three manners: a) rate of movement of the crosshead of the testing machine when not under load; b) the rate of stressing of the specimen; or c) the rate of separation of the crossheads under load. Any convenient speed of testing may be used as long as the load and strain readings can be made accurately.
- To measure elongation, increase the load until the extensometer indicates an elongation value equal to or greater than the minimum specified applicable specification. It is not necessary to determine the total percent elongation at maximum force.
- Run the test until specimen fracture to measure the breaking strength.
- Yield Strength
- Elongation
- Breaking Strength
ASTM A1061 | Metals | Multi-Wire Strand Testing
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