Corrosion is a major challenge for many design engineers and specifiers in the general industrial market. Choosing the right materials is critical to ensure optimal performance, as even the highest quality products can fail if not used properly.
Materials selection: three key questions to answer
Engineers must carefully analyse the proposed operating environment when selecting materials for industrial applications. Answering three important questions will help unearth potential problems and provide useful guidance on appropriate materials to use.
Fig. 1 Materials selection: factors to consider to minimize Stress Corrosion Cracking (SCC)
The three questions to consider are:
Q1. Is the material composition susceptible to cracking?
As this diagram shows, if potentially corrosive media (such as chloride containing compounds) needs to be contained and the material is susceptible to cracking, corrosion can occur. Material susceptibility is not purely about chemistry, though; factors such as material processing, specific microstructure and surface condition are also important.
Q2. Is the application environment potentially corrosive?
Environmental factors can include a range of parameters – chemical composition, flow rate, temperature, or electrode potential, which can be aggressive and lead to
corrosion and cracking.
Q3. Is the material concentrated load under tensile stress?
Stress can be imparted into a component in various ways – from service stress and vibration to residual stress derived from manufacturing processes or heat treatment.
Answering these questions helps to build a picture of what is appropriate for the individual circumstances. A small investment of time upfront can make a big difference to the longer-term success of an installation.
Materials selection and cost-efficiency
If a specific mix of materials was used successfully for a previous project, it can be tempting to rely on what has gone before. But that is not always a good idea.
With more than 300,000 product materials to choose from, materials selection presents a big challenge for many specifiers. It’s easy to feel spoilt for choice or be overwhelmed by the range of options available. But adding extra elements can complicate things… sometimes, just one material might be enough for the job! It’s important to know when adding a small amount of an element could increase costs, without any obvious customer benefit.
Conditions in many industries have changed; and it’s important to keep adapting materials to reflect this. Climate change is also key. For example, if summer temperatures have raised by a few degrees, some materials suitable in the past may no longer be appropriate.
It’s worth bearing in mind that:
Not all alloys are created equal, and even identical chemistries can lead to different final products. Parker’s 316 stainless steel A-LOK® tube fittings with min. 10% of nickel content has operated successfully in critical applications for 50+ years.
Good steel combines chemistry and processing. Parker tightly controls all specifications in terms of raw material quality, corrosion performance, mechanical properties, and heat treatment. Production routes are controlled from melting to a machined product; this ensures that customers get the best possible performance for their applications and a material that offers full traceability.
Managing risk when mixing materials
To get optimal results from your budget, it’s helpful to use the best material for the job, at the lowest possible cost. But when budgets are under pressure, some engineers may mix alloys on the same application.
Although using dissimilar materials seems like an easy way to save costs, it can be risky. Just because something looks strong and resilient, doesn’t mean that it will last for a long time. And mixing dissimilar materials for instrumentation can lead to SCC, where localised attacks at one point gradually progress to other areas of the system. SCC can lead to fatal failures.
NORSOK Standard M-001 Materials Selection states that
“‘At galvanic connections between dissimilar materials without isolation, it can be assumed that the local corrosion rate near the interface is approximately 3 times higher than the average corrosion rate. Particular systems may have higher corrosion rates depending on area ratio and material combinations.”
If a proposed application is highly demanding and requires expensive material, that’s likely to be important across the whole system. Ultimately the whole system operates in the same environment, contains the same media, and operates at the same pressure; therefore, it makes sense to use the same material throughout, rather than (say) using one material for the tubing and another for fittings.
Not everyone has access to a materials expert with their projects, but Parker’s specialist metallurgists bring many years of experience. This helps engineers identify the best materials for an application and predict likely failure risks. For example, using 316 stainless steel in seawater may not be a good choice because it is more susceptible to corrosion; but alternatives such as super austenitic stainless steel 6Mo (UNS S31254) or nickel alloy C276 (UNS N10276) may work, as they are designed to withstand chloride-containing environments with greater resistance to pitting or crevice corrosion.
Improving engineer confidence and skills with SBEx training
For some customers, specialist training provision can reduce the likelihood of potential fitting failures. For example, Parker’s Small Bore Expert (SBEx) training provides valuable guidance on correct fitting assembly and material selection. Suitable for fitters, technicians, and maintenance personnel, this course helps organisations to save time, reduce overheads, and increase safety.
Download our brochure with tips on smarter materials selection for corrosion control.
Article contributed by Clara Moyano, innovation engineer - Materials Science, Parker Hannifin, Instrumentation Products Division Europe
7 Oct 2020
Prevention is better than a cure. In coal mining, these words offer particularly good guidance. Underground mining presents numerous hazards ranging from structural collapses, flooding and explosions. The tremendous amount of dust generated by activities in a coal mine creates breathing-related problems for workers as well as maintenance issues for machinery. Dust can also create a potentially explosive environment. Injuries and deaths occur every year either from accidents or health issues caused by exposure to coal dust. Mining companies can dramatically reduce these risks by applying rigorous dust suppression safety measures.
This blog investigates dust suppression methods and evaluates preventative versus corrective techniques that can effectively be used to suppress dust in underground coal mines, reducing the risk to workers and equipment.
Coal dust is a known carcinogen that causes miners’ lung disease (pneumoconiosis). Dust in the atmosphere can also create an ignition hazard when mixed with gas. Coal dust buildup is often a root cause of premature maintenance and failure of mining equipment. To this end, preventative suppression is critical.
There are a variety of ways to suppress dust in coal mines that offer a varying degree of effectiveness and efficiency. The most common methods are:
Bag filter system uses fans to circulate the air and trap the solids in a bag. However, this type of system is maintenance-intensive and requires bag filter change-outs — which is not conducive to work in an underground mine.
Dry fog system requires electricity, making it impractical for work below ground level.
Water is an ideal solution because it takes advantage of the mine's existing water supply, forming it into a spray to suppress the dust as soon as it is generated at the coal extraction point and all other areas where dust is generated.
Preventative vs. corrective dust suppression using water Preventative dust suppression
Logically, if a problem can be prevented from happening, then the time and cost of fixing it can be saved. Preventing dust from becoming airborne is critical in dust suppression. Three important elements to successful preventative suppression using water include:
Control pertains to how the water is controlled. It may be controlled by the presence of coal on the conveyor or by the belt’s motion. In either case, the water is isolated before entering the system.
Filter technology is used to remove contaminants from the water to assure reliable system operation.
Spray refers to a predetermined volume and pattern in which the water is delivered to the coal before the dust is generated.
The figure below shows a typical belt conveyor transfer point dust suppression system has two options: paddle valve (A) or belt-driven valve (B). Both are designed to operate only when there is coal on the conveyor.
Corrective or symptomatic dust control is implemented after the dust is created and is more challenging than preventative dust control. Dust particles come in a range of sizes with some as small as 10 µm which is invisible to the human eye. These small particles are the most dangerous to workers and equipment because they can remain airborne for long periods of time and eventually find their way into miners’ lungs, onto and into machinery as well as outside of the mine itself. Small particles are also the most difficult to remove from the atmosphere. Airborne coal dust can be addressed correctively using sprays. The principal is that the dust agglomerates with the water, causing it to fall under gravity. However, if the water droplets are too large, then the airborne dust particles are just moved around, resulting in very little dust being removed. To effectively remove the dust, the water droplets and dust particles must be the same size. Hence, the design of the spray head is of great importance. With preventative suppression, the size of the particle is less important.
Dust suppression in Columbia | case study
Parker Conflow, a leader in the industry, works continuously with mining companies and equipment manufacturers to enhance products for preventative dust suppression. In one case, at CI Milpa in Colombia, a manufacturer of metallurgical coal, Parker Conflow engineers designed two dust suppression systems for a mine as well as a fire suppression system on a roadway.
“We are focused on continually improving the efficiency and safety of our production sites and the Parker Conflow systems are an important part of this. We chose to work with Parker Conflow, because of the company’s expertise in the manufacture and installation of dust and fire suppression systems and are very pleased with the result.”
— David Fernando Jaimes Mojica, CI Milpa
Preventive coal dust suppression is vital to ensuring the health and safety of workers and protecting mining equipment from costly downtime and failure. For over 60 years, Parker Conflow has been providing dust suppression, fire suppression and water control equipment and services that help protect workers in the coal mining industry worldwide.
After more than a century of experience serving our customers, Parker is often called to the table for the collaborations that help to solve the most complex engineering challenges. We help them bring their ideas to light. We are a trusted partner, working alongside our customers to enable technology breakthroughs that change the world for the better.
This blog was contributed by Gary Wain, product manager, Parker Conflow.
2 Jul 2020
The Oil & Gas industry sector is driven by safety and has been for over 60 years around the globe. Whilst the industry has had issues with incidents, it has been proven that by adhering to good working practices and following recommended installation techniques and procedures, these incidents can be minimized.
In summary, well trained, skillful engineering teams can help to reduce incidents and improve safety on Oil & Gas facilities. The key to this is for Owner Operators to ensure personnel are well trained and competent in their roles.Human errors are the main cause of Hydrocarbon Release (HCR) incidents
In the North Sea, HCR have been measured for many years and it is estimated that over half of HCR incidents are linked to or caused by human error (Source: Hydrocarbon Release Reduction Toolkit, Step Change in Safety).
Here, we will look at these human errors and identify the common ones in Small Bore Tubing (SBT) systems that can occur in Oil & Gas installations.
In instrumentation systems, leaks represent one of the most critical safety hazards. Common faults include, but are not limited to:
As these systems can carry hazardous substances, they have the potential to cause harm to personnel and equipment.Well trained personnel mean fewer issues
A well structured Small Bore Training (SBT) course delivered by well trained and experienced individuals can help eliminate these risks. Typically, a good course should address:
The objective of such training is to up-skill new recruits and apprentices whilst at the same time offering helpful tips and reminders to more experienced engineers. Everyone should leave the course having learned something new and being able to install connections safely.Parker Small Bore Expert (SBEx) training course
The Parker Small Bore Expert (SBEx) training course is designed to offer all of the above and the benefits to the engineers are:
It’s a sobering thought but the HSE (in the UK Oil & Gas industry) has consistently found that approx. 26% of SBT connections contain faults and typically these faults are aligned with the ones identified above (Source: Hydrocarbon Releases Offshore Information Sheet No. 2 / 2009, HSE).
Investment in the Parker SBEx Training Course can help address all of these challenges. Our goal is to help eliminate installation errors and reduce the potential for pressure related accidents. At Parker we are committed to providing your engineers with the right training courses via our trusted partners and distributors around the globe.
‘’Hydrasun, for over 30 years, continues to support the global energy sector, and other industry sectors, with training and technical competence at the heart of our service delivery. Hydrasun’s commercial training department has delivered over 1000 Parker SBEx courses to industry, training over 2700 delegates, in just the last 6 years alone, supporting our customers training and competency requirements, focussing on raising standards on safe working practices and procedures, and to ensure that Industry continues to deliver safe and reliable operations.’’
Stuart Gardiner, Hydrasun Group Operations Director (Directly responsible for HSE, Quality and Training)
Article contributed by Dave Edwards, Fittings Product Manager, Parker Hannifin Manufacturing Ltd., Instrumentation Products Division, Europe
21 Apr 2020
One of the biggest challenges faced by transport managers is how to decide exactly which product you require to meet your needs. It all depends on what your vehicles are running on and carrying; why, where, when. A highly-pressurised liquid fuel in sub-zero conditions requires very different sorts of fittings to a gas in tropical or desert heat. Here is the quick guide to using our ‘STAMPER’ method to maximise quality and reliability when it comes to specifying and choosing the right product for the transportation industry.Wrong product, wrong results
With almost limitless variables in different parts of the industry across the world, it’s no surprise that companies sometimes request the wrong parts, and end up paying the price in reduced productivity, missed schedules and downtime. All of Parker’s products are manufactured to the highest, quality-controlled specifications, but if it’s the wrong part in the wrong place at the wrong time, then performance and safety might be at risk. And during the current pandemic emergency, that’s something you can definitely do without.STAMPER makes it simple
To keep things easy and avoid this problem, follow the STAMPER approach to identify and order exactly what you need. STAMPER is the easy-to-remember acronym that will set you and your customers on the right route to reliability. Just seven letters to cover everything you need to consider, and put you in control.So here is STAMPER:
Fittings sizes vary enormously, between 6 and 25mm – which do you need?
In a global market, you need to cater for outside conditions as cold as -40oC or as hot as +60oC, and engines running at +140oC or even higher. Can the components in your systems handle such extremes?
Vibrations from engines and road surfaces can affect how products perform, and temperatures can fluctuate widely within a few hours.
What materials are you using or transporting, and what sort of connections do you need to suit the substances on board?
Working pressures up to 350 Bar are commonplace and may be double this in the near future. Is what you’ve chosen up to the job, and will it last for as long as your vehicles?
Salt, sand, chemical spray and other road contaminants can cause corrosion, and the demands from these can change from region to region. Are you fully protected?
Parker’s robust supply chain and flexible production offers you peace of mind, backed up by the experience and problem-solving abilities of our expert team. We focus on supplying the right products, so you can keep your eyes on the road and your business.
This infographic shows how STAMPER can help you secure quality and reliability for different types of natural gas fuels that demand precisely the right sort of connection. Download full infographic.
STAMPER will ensure you ask yourself the right questions to pinpoint the most suitable parts for all your transport purposes. Try it today, and contact us if you need any extra help or advice before ordering from our range.
At Parker, we know transport and want you to feel confident and comfortable in the driving seat when it comes to choosing the products you need.
Be sure and safe with STAMPER.
Article contributed by Dave Edwards, Fittings Product Manager, Parker Hannifin Manufacturing Ltd., Instrumentation Products Division, Europe
6 Apr 2020
Parker was recently approached by ENERAZ LLC, engineering subcontractor of Azpetrol Ltd. LLC and the biggest operator of filling stations in Azerbaijan, to provide several site-critical CNG distribution tube lines for the brand new CNG bus filling station in Baku.
Fitted with 14 CNG dispensers, 6 CNG compressors, 3 gas dryers and 3 chillers, the CNG filling station, which is located in the Narimanov district of Baku city, will be used by 300 buses of BakuBus LLC.Leak-free gas distribution lines for a safer environment.
Nearly 2,000 metres of Parker seamless tubes together with A-LOK® two ferrule tube fittings manufactured by Parker Instrumentation Products Division, Europe are among the key components to have been fitted onsite.
“As with all high-pressure gas fuelling systems, ensuring environmentally-safe CNG distribution was one of the main priorities for Azpetrol. This is something we’ve been able to guarantee by providing tubes and fittings that have been specifically designed to provide leak-free connections along the highly pressurised distribution lines.”
Murad Jafarov, Parker’s Azerbaijan Area Manager.
Image. 1. Parker's A-LOK® two ferrule fittings and tubing installed on three CNG compressors at the fuelling station.Superior corrosion resistance.
Not only do Parker’s CNG components guarantee leak-free distribution, they’ve been manufactured to withstand the corrosive effect of being exposed to the elements over a sustained period of time. The components are also robust enough to withstand the vibrations generated when the tube lines are being used.
“While this may have been the first time we’ve worked with Parker, we were aware of their products on board CNG vehicles, as well as within the wider CNG refuelling infrastructure across the world, which now includes Azerbaijan’s newest bus filing station. Having Parker’s components onsite has provided us with peace of mind that the risk of gas leaks, and the associated environmental impact is being kept to an absolute minimum now, and for many years to come.”
Elchin Mammadov, Head of Supply Department at Azpetrol.
Image. 2. A-LOK® two ferrule fitting with unique SuparcaseTM ferrule treatment offers excellent corrosion resistance and vibration protection.
Learn more about Parker Instrumentation Products Division's natural gas solutions for the transportation industry.
Article contributed by:
Murad Jafarov, Azerbaijan Area Manager, Parker Sales Company Central & Eastern Europe
Dave Edwards, Fittings Product Manager, Parker Hannifin Manufacturing, Instrumentation Products Division, Europe.
17 Mar 2020
When designing a leak-free instrumentation system, one of the first steps to ensuring safety and reliability is to select the right tubing for the intended application. No system integrity is complete without this critical link and its compatibility with the rest of the components. In this post we list four key parameters to consider when selecting quality instrument tube for use with Parker A-LOK® and CPITM tube fittings.
Parker’s instrument tube fittings have been designed to work in a wide variety of applications that demand the utmost in product performance. Their compatibility with selected tubing is critical for providing consistently high-level of reliability.1. Material compatibility
The most important consideration in the selection of suitable tubing for any application is the compatibility of the tubing material with the media to be contained. Table 1 lists common materials and their associated general applications. It also lists the minimum and maximum operating temperatures for the various tubing materials.
In addition, Parker instrument fittings are designed to work on like materials. Stainless steel fittings should be used only with stainless steel tubing, 6MO fittings with 6MO tubing, etc. The practice of mixing materials is strongly discouraged.
Table 1. Common tubing materials with their applications and operating temperatures.2. Tubing hardness
The key is to select tube material which is softer than the tube fitting material. For example, Stainless Steel tubing should be specified as Rb 80 or less hardness value. Parker A-LOK® / CPI™ Tube Fittings have, however, been tested on tubing up to Rb 90 hardness level with excellent performance.3. Wall thickness
Proper wall thickness is necessary to accommodate accepted safety factors relative to desired working pressures. Tube tables published in Parker’s literature, list the tube Outside Diameter (OD) sizes and Wall Thickness combinations per material for safe use with Parker A-LOK® and CPITM tube fittings. Do not use tube with wall thickness values which fall outside of the table ranges.
All working pressures are calculated following the recommendations contained within the ASME B31.3 Chemical Plant and Petroleum Refinery Piping Code and ASME B31.1, Power Piping. All calculations are confirmed via rigorous and extensive testing procedures at our Parker R&D Laboratories. Each calculation utilises an allowable stress figure that incorporates a 4:1 factor of safety.
All testing is carried out to replicate actual working conditions where possible. Parker does not ‘support’ tube to facilitate failure at certain points as this does not truly represent the forces that our products would see in ‘real-time’ applications.
Not all manufacturers support their assemblies’ pressure rating claims with extensive testing. In these cases it is important to understand the implications associated with using unverified recommendations.Note: Gas Service
Special care must be taken when selecting tubing for gas service. In order to achieve a gas-tight seal, ferrules in instrument fittings must seal any surface imperfections. This is accomplished by the ferrules penetrating the surface of the tubing.
Penetration can only be achieved if the tubing provides radial resistance and if the tubing material is softer than the ferrules. Thick walled tubing helps to provide resistance and the table below provides a range of wall thickness options available for safe use with Parker tube fittings. The ratings in blue indicate the combinations of diameter and wall thickness which are not suitable for gas service.
Table 2. Maximum working pressures (in psig) for imperial tube in 316/316L Stainless Steel material based on tube O.D. size and wall thickness combinations.4. Elevated temperatures
At elevated temperatures, a de-rating factor should be applied to the working pressure listed in the Parker tube tables. Please see the table below for the de-rating factors for the common materials Parker offers in our A-LOK® tube fittings range.
In all cases, tube fitting assemblies should never be pressurised beyond the recommended working pressure.
Table 3. This table lists the de-rating factors which should be applied to the working pressures for elevated temperature conditions. Simply locate the correct factor in this table and multiply this by the appropriate value in the pressure tables e.g. Table 2 (above) for 316/316L SS.
* Dual-certified grades such as 316/316L, meet the minimum chemistry and the mechanical properties of both alloy grades.
Register today for our industry-leading SBEx (Small Bore Expert) training and learn how to specify and install efficient, safe and leak-free small bore tubing systems.
The Right Tubing + The Right Fitting + SBEx Training = High Integrity Solution.
Article contributed by Dave Edwards, product manager - tube fittings, Instrumentation Products Division Europe.
19 Nov 2019