If you’re a third-party testing company that provides on-site testing of plant equipment, you’ll have experienced the pressure to get a large amount of testing completed in the crucial downtime window.
Extending the downtime is costly, yet you need to take the time to get reliable, accurate results. How can you find the sweet spot between fast testing times and 100% accuracy for on-site PMI (positive material analysis) testing?
The two main challenges with refinery and other industrial plant equipment are corrosion resistance and weldability. These can be improved significantly by using the right grade of stainless steel.
Testing companies are often tasked with checking large quantities of steel piping (and other components) to verify the composition. This checking must be done on-site. It’s not an option to remove sections of installed pipework for lab-based testing; it would be too costly for the plant to remain down for this length of time.
If a sub-standard grade of steel is found, it must be exchanged for a new, correct, part. The replacement part will also need to be checked to verify the composition. The challenge is to complete thorough testing with high accuracy without increasing the downtime window of the plant.
Usually the performance of the steel part is down to whether a single element is present – or removed – from the alloy. For example, in many cases the fairly standard 304 grade of stainless steel provides corrosion resistance that’s perfectly adequate. However, for some highly corrosive environments, grade 316 is essential. The main difference between the two grades is the presence of over 2% of molybdenum and higher nickel content in 316.
When it comes to weldability, the situation is a bit more complex. This depends on the alloy’s carbon content. If the carbon content is below a certain limit, then the steel is weldable. But as the carbon content increases then weldability decreases. Carbon also affects hardness, strength and ductility. Understanding the performance of specific alloy relies on an accurate carbon content figure.
When you’re constrained within a downtime window of a couple of hours, you only have time to test once. The tool you need will be the one that tells you everything you need to know. OES (optical emission spectroscopy) is the only technique that will give you the accuracy you need across the whole range of elements. Other analytical techniques, such as XRF (X-ray fluorescence), are perfect for other types of test, but when you need to measure carbon content for weldability, then OES is the only way to go.
Hitachi High-Tech’s PMI-MASTER Smart provides the level of accuracy you need for precise PMI measurement of safety-critical plant equipment. It’s lightweight and portable at only 15kg so you can easily get to those hard-to-access places on-site. It has an extremely fast start-up time because it doesn’t need a heating system, unlike other portable OES analysers on the market.
This means that you can take a measurement of all the crucial elements – including carbon – in just minutes. With PMI-MASTER Smart you can get through a large amount of testing in the few hours you are given while the plant is down and have confidence in the results.
With PMI-MASTER Smart, there’s no second-guessing. Fast, reliable and accurate results all in a portable device. For more information, get in touch to talk to one of our experts