What is a Tensile Strength Test?
Do you remember playing with playdough as a kid, or last week? I do. Did you ever just grab a ball of playdough and pull it until it broke? If so, congratulations! You’ve conducted a tensile strength test. Specifically speaking, a tensile strength test is when a material is put under a controlled tension until it fails. Tensile testing is mostly to test the strength and elasticity of a material. If you often ask, “How much can this stretch before it breaks?” You may want to become a tensile testing tech.
Professional testing is done on machines that clamp down on either end of a material and pull the material along a single axis at a constant speed. Most materials will fail at a single point, called a neck, where it will become thinner than the rest of the material before breaking. Special monitors record data during the test to calculate such things as breaking strength, fracture point, elasticity, and permanent elongation.
Breaking strength: How much force causes it to break.
Fracture point: Where the material breaks.
Elasticity: How much the material can stretch before breaking.
Permanent elongation: After breaking, how much longer is the material permanently.
Metals, plastics, polymers, ceramics, and composite materials are the most tested materials. Some specific examples include rebar, tire rubber, plastic containers, textiles, sutures, cardboard, and metal piping. In fact, it’s not just single materials that can be tested. Tensile strength testing is often used to test anything that melds two materials together! Examples of this are glued materials, tied materials, and welded metals. If a material is meant to contain, reinforce, carry, lift, or many other actions, it has likely undergone a tensile strength test.
What interests Critical Systems, Inc. is the strength of welded metal piping. We are always striving to create stronger welds, so what we look for is if piping welded with our equipment breaks at the weld or elsewhere. Success is when the pipe breaks at the coupling or along the pipe itself. What does that mean for our welds? It means that our welds result in a stronger bond than the metal on its own.
The beauty of orbital welding is that it is an automated process. Tensile strength testing multiple welds shows inspectors that our process is both sound and replicable! We combine the results of visual inspections and accredited testing facilities to assess whether a weld passes or fails. The tensile strength testing these third parties do is critical to affirming our successful programs.
To dive a little deeper, tensile testing plays a key role in assessing materials for:
Strength assessment: Tensile strength, breaking strength, maximum elongation and reduction around a material
Material behavior prediction: Especially important for groundbreaking technology. The data behind how a material acts is vital to benchmarking and process refinement.
Safety Assurance: Paired with the above, most people are skeptical of innovative technology. Tensile strength testing confirms when new processes or materials are “better” than their fellows. It can also pave the way for new certifications and standards.
Data driven benchmarks: Data is the best friend of engineers, designers, and manufacturers. Tensile testing provides a plethora of data to help adopters “trust but verify” materials.
To recap, tensile testing is essential for ensuring material fitness, safety, and informed engineering choices. This is especially important in critical fields like Medical Gas Installation.
More on that later though.