Accurate, Effective Stress Measurements in Materials
Stress has an enormous impact on how materials and metals perform, but is not always easy to measure. Our engineers apply decades of experience to help you accurately and effectively measure strain in your specific application, ranging from stress in pipelines and storage tanks to commercial products. Using practices like the well-established hole drilling, tube splitting, and x-ray diffraction, we can help you understand and engineer based on the stresses of your application.
What is Stress Measurement For?
Stress measurements provide a fast, quantitative way to understand how materials are affected by fabrication or processing. For example, many materials have varied stresses left after being cast, forged, and/or welded (known as residual stresses). Those stresses will combine with the operating stresses during service, and can result in:
- the formation and growth of cracks,
- hydrogen accumulation resulting in hydrogen embrittlement,
- warping and distortion,
- increased corrosion rates, and
- susceptibility to stress corrosion cracking.
The most accurate way to determine those stresses is direct measurement. We use the ASTM E837 hole drilling method for many applications, as well as tube splitting and sectioning methods in some circumstances. In the hole drilling method, a small hole is drilled a few thousandths of an inch at a time in the center of a set of strain gauges, as in the picture below. The strains are measured as they change with depth, and the data can then be used to calculate the magnitude and type of stresses at various depths into the material.
Why is Stress Measurement Needed?
- Can be performed on-site or in our laboratory. Our trained technicians can be at your site within a matter of hours in most cases.
- A very small hole is drilled, which can be removed by grinding and which is typically within the corrosion allowance for many materials.
- Hole drilling for stress measurement is a rapid and accurate way to check the stress in welds, forgings, castings, and clad components.
- Have greater confidence in your decisions during turnarounds, shutdowns, and fitness-for-service evaluations by using accurate stress measurements that can be incorporated into FEA and fracture mechanics analyses.
Where to Get Stress Analysis Performed?
We offer competitive rates for laboratory and on-site stress analyses from our Houston headquarters. Contact us to learn what’s best for your application and to discuss your scope of work.