More Than 1,000 QS50K Pistons Delivered – And Counting!

In 2019, following an extensive research and testing period, we have introduced the first QS50K pistons into the market. It was the beginning of a lasting success story: Ever since, we have produced and delivered more than 1’000 pieces, to many different customers.

These pistons are now installed all around the world, in ocean going vessels and in power plants. They are performing extremely well and achieve time between overhauls (TBO) that hitherto were unthinkable. The earliest QS50K pistons have accumulated well over 30,000 running hours and are still in service!

Rebuilding the piston ring grooves
Rebuilding the piston ring grooves

Benefits of the QS50K technology

With the introduction of the QS50K coating technology, QuantiServ has redefined the piston reconditioning process. This proprietary technology was developed by QuantiServ and offers the following important advantages:

    • Extremely durable, wear resistant coating, resulting in very long life-time / time between overhauls (TBO)
    • Fully automated process carried out by a robot, resulting in a top-quality product due to the robot’s very high accuracy, repeatability and consistency.
    • Faster than chromium plating, therefore shorter turnaround times
    • Less heat input into the piston, eliminating any residual stresses that over time could develop into cracks
    • Environmentally sound, non-toxic process

Availability

We offer the QS50K technology for any engine brand and for any cylinder bore above ø 48 cm. The QS50K pistons that we have delivered so far covered the bore range, from ø 48 cm to ø 98 cm. They were destined for engines manufactured by the big three OEMs, in an approximately 45%/45%/10% ratio.

At this moment, our recon centres in Kruiningen (The Netherlands) and Suzhou (China) are equipped with the required machinery to offer this product. Our large recon centre in Singapore will follow very soon.

24,000 Hour Ring Groove Life Time. Guaranteed!

The quality of our QS50K coated ring grooves is so good that we now offer a 24,000 hour* warranty on fully reconditioned, QS50K coated two-stroke pistons!

Contact us for details

*pro-rata, 24,000 running hours or three years after delivery, whichever comes first

To give maximum flexibility to our customers, we offer three different ways of working to chose from:

  1. Reconditioning on exchange. The customer gets a newly reconditioned component delivered from one of our four reconditioning centres. Once he has installed the component into his engine, he returns his old part to us.
  2. Reconditioning of the customer’s own part. The customer sends the component to be reconditioned to a QuantiServ reconditioning centre, where it undergoes professional reconditioning after which it is returned to the customer.
  3. Straight sale. The customer purchases a reconditioned piston from us, without returning an old one.

We can apply the QS50K coating to pistons that are undergoing full or partial reconditioning.

Full reconditioning

The entire top surface and ring groove area is first machined off and then rebuilt by robotic MIG or SAW welding. Thereafter, the piston undergoes final machining before the QS50K coating is applied to the ring grooves. The last step is grinding of the ring grooves, which completes the full reconditioning process.

If it is requested by the customer, then we can coat the top of the piston by a protective layer of Inconel. This can be a good solution for engines that suffer from excessive hot corrosion at the piston top.

Partial reconditioning

If only the ring grooves are worn and if a piston is in otherwise good condition, then partial reconditioning is possible. A precondition is, however, that none of the ring grooves has worn so much that not only the chromium layer but the steel substrate itself has worn. In this case, partial reconditioning is not possible and full reconditioning is the only remedy.

During partial reconditioning, any remaining chromium is removed before the QS50K layer is applied to the ring grooves. All mating surfaces will be skimmed, to remove any signs of fretting corrosion and if there are small internal cracks, then these will be repaired too.

 

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Our reconditioning centres

We operate four reconditioning centres that are strategically located along major shipping routes: Singapore, Kruiningen (The Netherlands), Suzhou (China), Dubai. Each of the four centres carries a large inventory, so it can offer components on exchange in addition to reconditioning the customer’s own part. Both ways of working are available, it is entirely the customer’s choice.

Our reconditioning centres are the most modern ones within our industry. Welding and QS50K coating is typically performed by robots and machining is done on numerically controlled (NC) machines.

QuantiServ Reconditioning Centres
We operate four reconditioning centres globally.

This enables us to provide consistently high quality and short turn-around times at attractive prices.

 

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QuantiServ Suzhou Workshop
The QuantiServ reconditioning workshop in Suzhou, China. The others are in Singapore, Dubai and Kruiningen (The Netherlands).

“Reconditioning” Must Mean More Than to “Put Into Good Shape Again”

Component reconditioning is very popular

Component reconditioning has many advantages. This is especially true in case of large, heavy components:

  • Reconditioning usually represents a cost saving of 50 – 70% compared to replacement
  • Reconditioning a component nearly always takes up significantly less time than fabricating a new one
  • Long lead times or supply chain crunches are less of an issue, as supply chains are shorter and simpler
  • No new part might be available when one is needed. To reduce risk and stock keeping costs, OEMs manufacture and sell spare parts for ever shorter time periods only.
  • Reconditioning results in a smaller carbon footprint than replacement

Given these advantages, it is hardly surprising that component reconditioning has been widely used for many years in industries such as marine and power generation, where components are large and where equipment life is long.

But, what does reconditioning actually mean?

Dictionaries and thesauri usually equate the word “reconditioning” with “to put into working order again” or “to put back in shape”. Proposed synonyms are: To fix, mend, patch, renovate, repair and revamp.

This implies that the goal of the reconditioning process is to put the component back into the state it was before it got worn or damaged.

At QuantiServ, we are convinced that we should do much more than to put a component back into its original, unworn condition. We set the bar much higher for ourselves. After all, we are one of the largest reconditioning companies in our industry and we have in-house research and development resources, that enable us to continuously push  the technology envelope. Noblesse oblige, as the French proverb goes.

We believe that whenever a machinery component undergoes reconditioning at one of our four reconditioning centres, we are presented with an opportunity to not just put the part back to its original condition, but to improve on it. We habitually apply new technologies, modern materials and advanced processes to improve component design, leading to a better performance and extended Time Between Overhaul (TBO).

This sets us apart from all the low-cost reconditioning companies. These companies return to their customers components that – in the best of cases – perform as good as when they were new, but never better. Unfortunately, by so doing, these companies forego customer value by providing sub-optimal service.

There are many good examples of how we have lived up to our high standards and have engineered, manufactured and delivered to our customers improved components that have subsequently shown superior performance. An illustrative example comes from a power plant in the Caribbean, that suffered from very short TBOs. Pistons on these 90-bore engines had to be pulled every 3’000 running hours, to replace piston rings, pistons and, sometimes, even cylinder liners. To solve the problem of such unacceptably short maintenance intervals and component life-times, we have thoroughly analyzed and then redesigned some components of this 90-bore, two-stroke engines. Specifically, we have altered the number of piston rings, have coated the piston ring grooves with our QS50K material and have applied a coating to the piston skirts.

The result of these modification is that the TBO could be increased from 3’000 hours to 18’000 hours!

Three piston rings instead of five

In internal combustion engines, piston rings seal the combustion chamber. While the piston rings’ purpose is unambiguous, it is less clear how many piston rings are required, to get the job done effectively. Historically, four or five piston rings per cylinder were deemed necessary on low-speed, two-stroke diesel engines. Simulations and field experience collected by us in recent years has shown that on many engine types, pistons with only three or four piston rings perform better than those with five. “Less is more”, when it comes to piston ring tribology.

Anti-friction coated piston skirts

A well performing forced piston cooling system is essential, especially on engines that operate on heavy fuel oil (HFO) to maintain a relatively low and stable core temperature. If the piston temperature rises above a critical threshold, then galling, scuffing or seizing will occur due to thermal expansion and breakdown of the oil film between the piston and cylinder liner.

The performance racing industry has been using coated pistons for some time already for this very reason. These so-called anti-friction coatings, that are applied to the piston skirts, are essentially dry film lubricants with a very low friction coefficient. This results in low friction forces and a reduction of parasitic drag, while also decreasing heat saturation in the piston skirt and core.

A 90-bore two-stroke engine piston with three piston ring grooves (instead of five) and with an anti-friction piston skirt
A 90-bore two-stroke engine piston with three piston ring grooves (instead of five) and anti-friction piston skirt

Anti-friction coatings offer the following benefits:

  • They act as a thermal barrier coating and reduce metal-to-metal contact
  • They increase component life time and TBO due to a lower wear rate
  • Reduced friction (a parasitic loss) results in a lower fuel consumption
  • They support oil film formation and therefore reduce the risk of galling, scuffing and seizing, particularly under challenging operating conditions such a running-in, high load operation and load changes

QS50K pistons

An excellent example of us improving engine component design is the development of our QS50K pistons. From a few years ago, many customers reported excessive wear in the piston ring grooves. The customers informed us that pistons with chromium plated ring grooves, which has been the industry standard for decades, would only last for a few thousand running hours. As reported this applied, in equal measure, to new as well as to reconditioned pistons and to many different engine types.

Our engineering and development colleagues started to investigate. They eventually developed an entirely new process of coating the piston ring grooves. They replaced the chromium in the ring grooves with a very advanced, proprietary material formula which has been proven to easily last for 20’000 hours and more. The successful development and market introduction of the patented QS50K coating process is a good example of how QuantiServ developed a solution to problems reported to us by our customers.

Since its introduction, more than one thousand QS50K pistons have entered service. The earliest ones have meanwhile accumulated well beyond 30’000 running hours!

Do talk to us if you have a specific problem with your installation. If machine uptime or performance is lower than it should be, if components wear out too fast, or if they fail prematurely. It is quite possible that we a solution available – perhaps we have already solved a similar problem for another customer. And if we do not have a tried and tested solution ready, then we will be happy to investigate and look for one.

In the case of the Caribbean Power Plant we have also supplied special piston rings that the engine OEM does not have in his portfolio for this engine type. This, in addition to implementing the modifications described above.

 

Our Reconditioning Offering

Sustainability

QuantiServ’s enduring commitment towards resource reduction and sustainability is demonstrated by our membership in the Association for Sustainable Manufacturing (MERA). We proudly carry MERA’s Manufactured Again Certification Mark, which is a recognizable symbol
that represents the quality, value and sustainability of our processes.

Image Gallery

Example of anti-friction coating on 90-bore piston skirts in our reconditioning centre in Kruiningen, in the Netherlands. Once the anti-friction coating is applied, the piston skirts get cured in an oven. As is usually the case, reconditioning of these piston skirts included the replacement of the four bronze bandages.

A 90-bore two-stroke engine piston with three piston ring grooves (instead of five) and with an anti-friction piston skirt