Use of Portable Automated Ball Indentation System to Evaluate Mechanical Properties of Steel Pipes

In this study, portable automated ball indentation technique (PABI) has been applied to evaluate the few mechanical properties of steel pipes and excellent correlation has been obtained with conventional test results. A PABI system, developed and fabricated at National Metallurgical laboratory, India, was used to evaluate the mechanical properties. The operational parameters were optimized for various materials to measure yield strength, ultimate tensile strength, true-stress versus true-plastic-strain curve, strength coefficient (K), strain-hardening-exponent (n), hardness (BHN) and fracture toughness (K_JC). This unit can be mounted on components with curved or flat surfaces and properties of the material could be evaluated by making a very small indentation. Also it has provision to use small test specimens. Automation of the test, where a computer and test controller were used in innovative ways to control the test as well as to analyze test data made it simple, accurate, economical and highly reproducible. A LabVIEW BASED S/W was made to control the unit.