Frequently Asked Questions

Destructive testing requires a piece of the material that is to be tested, to be scraped away for alteration or analysis. Nondestructive testing can be done while the material is being used, thus not causing any damage or alteration to it.

Nondestructive testing helps companies reduce costs as the material to be tested can survive the process unharmed, thus saving resources. Nondestructive testing is also safe as it consists of methods that are harmless to humans. Nondestructive testing is also known for its high efficiency rate that involves thorough methods that offer a quick evaluation of materials. Nondestructive testing is also highly accurate and predictable without inflicting harm to workers.

Nondestructive testing is widely used in numerous industries all over the world. This is in view of how convenient visual inspections can be done virtually anywhere. Some of the industries that use nondestructive testing as a requirement for their companies include power generation, oil and gas, mining, chemicals, automotive, aerospace, mining, and maritime.

There are several benefits of using nondestructive testing but the main advantage is having the tested material intact and ready to be used again without any alteration or damage. This helps the company to save on the repair and replacement of their resources. Nondestructive testing is also known to be safe and highly accurate which are the two factors companies need to ensure the testing process gets implemented efficiently.

• Testing process is fully automated and computer-controlled
• Testing produces highly accurate results
• Testing can be performed directly on the component, thus eliminating the need to destroy the component and cut samples.
• The nondestructive ABI® test provides a stress-strain curve and fracture toughness data [Haggag Toughness Method (HTM)] eliminating the need to perform Tensile and Fracture Toughness testing. And the test takes less than two minutes to perform.
• For failure analysis, new alloy development, or when testing at extreme high/low temperatures, only small amounts of material are needed. The smallest specimen size is 0.2" x 0.2" x 0.1" thick. The specimens need to be prepared for indentation testing with two parallel smooth (63 rms or better) surfaces.•Small specimens can also be mounted in Bakelite (avoid epoxy since it is too soft and will affect the test results).
• Test specimens may also be the broken halves of traditional destructive specimens (e.g. tensile, Charpy V-notch, fracture toughness).
• The ABI®test technique is the only test that provides accurate stress-strain curves on small welds and their heat-affected-zones (HAZs). It can provide an overlay of the stress-strain curves from the base metal, weldment, and the HAZ for instant comparisonof mechanical properties. Weld specimens should be properly etched to reveal the HAZ

Automated Ball Indentation ® (ABI® ) is a specific indentation test that uses a ball indenter and the Haggag partial unloading technique to accurately measure the tensile and fracture toughness properties of metals. Instrumented Indentation Testing (IIT) is a general term for ultra low force nanoindentation using a Berkovich pyramidal indenter and is used to examine thin films and coatings for nano-hardness (Martens Hardness).

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Linear geometry indenters can only produce hardness versus depth, and you get one value of strain regardless of increasing depth. Nonlinear geometry (Ball) indenters produce increasing values of strain and stress as depth increases. In order to obtain macroscopic properties, such as a stress-strain curve, the indenter size should be several times the grain size of the material

ABI® tests are localized and nondestructive and measure the following key mechanical properties:

• Fracture master curve analysis
• Fracture toughnessvalues
• Maximum Allowable Operating Pressure (MAOP)
• Reference temperature
• Strain-hardening exponent (n)
• Strength coefficient (k)
• True-plastic strain curve
• True-stress
• Ultimate strength
• Uniformductility
• Yield strength

Internal pressure or a hoop stress condition creates ONLY elastic stress on the internal surface of an in-service pipeline. The maximum allowed hoop stress cannot produce yield strength of the pipe in order to avoid pipeline bulging and any potential failure. Hence, the elastic stress (which is lower than the yield strength by the margin of safety used in the MAOP) cannot affect the test results of the ABI®test.

Yield strength cannot be measured by the hardness test. In pipeline steels yield strength (YS) is the stress at a small strain value of 0.5%. Any hardness number could be correlated empiricallyto ultimate tensile strength (UTS), which is the stress at 8-10% strain. UTS is usually much higher than YS and the two are not interchangeable.

Why the Hardness Test can Not Determine Yield Strength