Hello Pipe Enthusiasts!
Destructive Testing on steel pipe is a procedure in which the sample is intentionally destroyed to measure its mechanical properties. The goal is to ensure the pipe fully meets specified strength, ductility, and toughness requirements before field deployment, as mandated by standards such as ASTM A53, ASTM A252, API 5L, API 2B, API 5CT, or SNI. Here are some key terms in Destructive Testing at PT Bakrie Pipe Industries:
1. Chemical Analysis (Spectrometer)
Chemical analysis is performed using a spectrometer to measure the concentrations of carbon, manganese, silicon, sulfur, phosphorus, niobium, titanium, aluminum, nitrogen, copper, chromium, nickel, molybdenum, and boron with high accuracy. The results verify that the pipe’s chemical composition meets the required quality standards.
2. Tensile Test
The Tensile Test determines the maximum tensile load the pipe can withstand before fracture. A specimen cut from the pipe material is pulled in a testing machine until it breaks. Key parameters—yield strength, ultimate tensile strength, and elongation—are compared to the minimum values specified in the MPS document or customer requirements.
3. Bending Test
The Bending Test subjects a pipe sample to a specified angle or radius to assess its ability to deform without cracking. This evaluates the material’s elasticity and plasticity under lateral force.
4. Hardness Test
The Hardness Test measures the material’s resistance to permanent surface deformation, typically using the Brinell, Rockwell, or Vickers method.
5. Charpy Impact Test
The Charpy Impact Test measures the material’s toughness under sudden impact, especially at low temperatures. A notched bar specimen is struck with a weighted pendulum, and the energy absorbed in the fracture is recorded. This test is conducted on both base metal and weld metal and is critical for pipes used in extreme environments such as offshore or other low-temperature conditions.
6. Metallurgical Examination (Macrograph/Micrograph Test)
- Macrographic Test: A section of the weld is cut, polished, and etched to reveal macro-scale features such as porosity, incomplete fusion, or undercut. This validates welding quality, including fusion line integrity and weld-metal flow.
- Micrographic Test: Similar to macrography but at higher magnification to examine the steel’s microstructure—grain size, phase distribution (ferrite, pearlite, martensite), and inclusion content. Etching enhances structural detail for microscopic evaluation.
7. Burst Test
The Burst Test measures the maximum internal pressure a pipe can withstand before rupturing. The sample is filled with a fluid (usually water), and pressure is increased gradually until failure. The burst pressure is a key parameter for determining safe operating limits.
8. Drop Weight Tear Test (DWTT)
DWTT is a large-scale impact test that assesses the material’s fracture mode (ductile vs. brittle) and shear area percentage.
A pipe segment specimen is struck by a heavy weight dropped from a specified height. The fracture surface is examined visually, and the percentage of ductile fracture indicates pipe toughness. DWTT is commonly used for large-diameter pipes or those intended for high-pressure gas service.
9. Residual Stress Measurement
Residual Stress measurement assesses internal stresses remaining in the material after machining, forming, or welding. These stresses can influence stress-corrosion cracking, fatigue performance, and dimensional stability during service.
Bakrie Pipe Industries Laboratory
BPI’s laboratory is equipped with comprehensive, state-of-the-art testing facilities and has been ISO/IEC 17025:2017–certified by the National Accreditation Committee, ensuring technical competence and reliable test results. We offer complete testing solutions to verify that your steel pipes meet all required standards. Our expert laboratory team is ready to assist you.
That concludes Important Terms in the Steel Pipe Inspection Process (Part 3), covering Destructive Testing of steel pipe specimens. See you in the next article, and feel free to share your insights in the comments. Stay tuned for more updates only on #BPIPipeInsights!
