Selecting the most appropriate tubing for your hydraulic and instrumentation (H&I) needs can be challenging and there are several factors to consider. We’ve picked out some key questions to ensure you get the most from your tubing.
1. Will my tubes be fit for purpose?
Or, to put it another way, what do I want my tubes to do? It’s not as simple as it sounds.
When humidity exceeds 75% and temperatures rise, the risk of corrosion increases exponentially. Add to this saltwater in a tropical environment and poor quality seamless tubing will rapidly start to pit or corrode.
Tropical field trials by two of the world’s largest oil companies found tubing materials that would normally last 100 years or more in dry conditions could have a service life of five years or less in an aggressive chloride-rich environment.
Is your tubing up to the task?
2. Not all materials perform the same: how do I choose?
Ensuring the steel grades being used for your tubes meet ASTM and EN standards is a good start. But is that enough?
Even though different tubing may meet the same required standards, there can be big differences in performance levels.
For example, when it comes to alloy content, the minimum molybdenum percentage required by the international standard ASTM for the grade 316L is 2.0% and the minimum pitting resistance equivalent (calculated from the level of Cr, Mo, and N present in an alloy) is 23.
However, choosing an alloy with a higher molybdenum content can give you a higher PRE. So, while many materials might meet the minimum ASTM standards, choosing one that goes beyond the basics can provide superior anti-corrosion benefits.
3. Strength or flexibility – or both?
Can you afford to have wall collapses and cracks in your hydraulic or instrumentation tubing? Is the tubing you are currently using giving you controlled hardness for easy bending and leak-free connections? Beware: there are many definitions of what a good standard is.
You need consistency in the material’s hardness – not too stiff, not too pliable – to help you work quickly and with confidence. This is important whether you are using a hand-held bender, an automated bender, or even just a spanner.
For example, consistent hardness means you can make just the right number of turns with the spanner or ensure the right setting for hand-held or heavy-duty tube bender. The right hardness allows for accurate, tight radius bends of up to 180 degrees without the walls collapsing. Different hardness in the same tube batch can lead to difficulties when tightening the tube fitting.
Looking at industry standards again, the maximum hardness requirement for ASTM 316L tube is HRB 90, but materials with a lower HRB number can provide a tube that’s strong, yet softer than the standard, making it easier to grip and bend.
4. When and where can I get my tubes?
Time is money. You don’t want to be held up waiting for your tubes to arrive. And when they do come, it’s critical that the grade quality is consistent from batch to batch. So, make sure your supplier can meet your timeline and consistency needs. Choosing one that has both a global and local presence with a broad, in-stock range of tubing in various grades and wall thicknesses can ensure you get exactly what you need when you want it.
5. What about the environment?
The future of our planet has become an increasingly important issue and many companies have introduced sustainability measures into their production processes. A responsible steel manufacturer will be happy to share their sustainability and circularity goals for their company, materials, product development and global footprint.
6. Keeping it clean
Having contaminated hydraulic fluids in your pumps could lead to unscheduled maintenance or production stops - costing you millions. Small impurities can also affect other parts of your system. And nobody has time to clean new shipments of tubes, especially on remote sites like offshore oil platforms.
Selecting a supplier that rigorously cleans and plugs your tubes before shipping can prevent unplanned malfunctions and give you peace of mind.
Since 1980, Sandvik has supplied more than 100 million meters of consistently high-quality H&I stainless tubing to solve our customers’ most challenging problems. Speak to one of our experts about how we can bring you peace of mind.
By Andreas Furukrona, Product Manager