410 Stainless Steel has Many Advantages

Ideal applications for KVA Stainless processed martensitic stainless steel include:

• Agriculture
• Automotive Components & Structures
• Aviation Components & Structures
• Bridge Structures
• Gas & Oil Production/Pipelines
• Heat Exchangers
• Medical Devices
• Petrochemical & Process Piping
• Renewable Energy
• Sports Equipment (i.e. Golf Shafts, Lacrosse Sticks, Baseball Bats, Bicycles, Hockey Sticks, and Wheelchairs)
• Train/Rail Cars & Equipment and many more!

KVA Stainless - Applications - Martensitic Stainless Steel Tubing

KVA Stainless is selling tubing and offering license opportunities for their new, patented Martensitic Stainless Steel tubing fabrication as well as stamped and shelled structures/components.

KVA Stainless manufactures and sells seam-welded martensitic stainless steel tubing.

Agriculture, Automotive components & structures, Aviation components & structures, Bridge structures, Gas & Oil Production/Pipelines, Heat exchangers, Medical devices, Nuclear, Petrochemical & Process Piping, Renewable Energy, Sports equipment, Train/rail cars & equipment and many more!

Key advantages of KVA Stainless seam-welded tubing technology:

KVA Stainless processing can be used to produce martensitic stainless steel seam-welded tubes with consistent properties throughout, replacing costly high-performance specialty alloy tubing while maintaining performance and reducing both production and material costs.

Tubing Production

Continuous production of longitudinally seam-welded tubing has proven to be the lowest cost, most consistent method of making structural pipe and tube out of any alloy material. High production speed, excellent dimensional control, and wide availability of finished sizes make continuous roll-formed seam-welded tubing very attractive.

Unfortunately, many materials, including martensitic stainless steel (MSS) are not compatible with the high-speed welding and forming that continuous roll-formed tubing entails. In these cases, tube drawing and hot extrusion processes have been used to successfully produce seamless pipe and tube. These batch methods require many intermediate thermal processing treatments - which are inherently slow and very costly - and have limited the widespread economical use of MSS high strength tubular shapes.

Additionally, other high strength steels and advanced alloys cannot be made into seam-welded tubing without a significant loss of strength in the weld and heat-affected zone (HAZ). The end result is a non-uniform product, which may be prone to failure or splitting in the weld or HAZ either during forming or in service.

KVA Stainless' Seam-Welded Tubing

Recognizing the need for low-cost, high strength structural tubing, KVA Stainless founder, Mr. Ed McCrink, and development staff has implemented their patented welding and thermal processing technology to enable seam-welded MSS tubing. These technologies are the result of decades of metallurgical and thermal processing R&D and know-how. KVA Stainless' proprietary, simple to implement methods have overcome conventional difficulties, without resorting to lower-carbon, lower strength alloys and enables the production of ductile, tough and reliable low-cost MSS seam-welded tubing.

KVA Stainless processed MSS tubing exhibits a more uniform weld metal macrostructure than conventionally processed seam-welded tubing with less chromium carbide dispersion and segregation. Additionally, after a simple air-quench and temper heat treatment, which can easily be implemented in-line to the tube production process, a uniform, homogenous microstructure is obtained in the weld, HAZ and base metal - functionally equivalent to costly seamless tubing.

KVA Stainless seam-welded tubing can replace seamless MSS tubes, expensive austenitic stainless steel tubing, exotic titanium alloy tubing, or specialty ultra high strength steel tubes, welded or seamless. Additionally, fully martensitic alloys can be used to produce KVA Stainless seam-welded tubing; in contrast to current methods utilizing reduced carbon - and reduced strength - modified weldable martensitic grades. KVA Stainless MSS seam-welded tubing can benefit any market segment where component weight, strength and corrosion resistance are critical issues, providing a superior alternative to conventional alternatives.

Similar to low-alloy steels, maximum strength and hardness of seam-welded MSS tubing primarily depends on carbon content. Low carbon MSS grades, such as AISI type 410, have tensile strengths in excess of 200 ksi (1400 MPa) in the fully hardened condition. Tensile strengths in excess of 300 ksi (2100 MPa) are possible in the higher alloyed MSS grades of KVA Stainless seam-welded tubing.

Ideal applications for KVA Stainless seam-welded martensitic stainless steel tubing include:

• Agriculture
• Automotive Components & Structures
• Aviation Components & Structures
• Bridge Structures
• Gas & Oil Production/Pipelines
• Heat Exchangers
• Medical Devices
• Petrochemical & Process Piping
• Renewable Energy
• Sports Equipment
• Train/Rail Cars & Equipment

KVA Stainless Technology is Ideally Suited for High Strength Structural Applications

KVA Stainless is selling tubing and offering license opportunities for their new, patented Martensitic Stainless Steel tubing fabrication as well as stamped and shelled structures/components.

Agriculture, Automotive components & structures, Aviation components & structures, Bridge structures, Gas & Oil Production/Pipelines, Heat exchangers, Medical devices, Nuclear, Petrochemical & Process Piping, Renewable Energy, Sports equipment, Train/rail cars & equipment and many more!

KVA Stainless technology is ideally suited for high strength structural applications:

• Bridges
• Spaceframes
• Buildings (Structural Framing & Architectural Facades)
• Covered Structures
• Heliostat Frames (for tracking and stationary solar power modules and mirrors)
• And much more...

Please contact us for information regarding your specific application, and how lightweight KVA Stainless technology is the cost-effective way to reduce transportation, installation and fabrication costs, increasing strength and durability.

Reduce Manufacturing Costs for Stamped, Welded, or Tubular Components

KVA Stainless is selling tubing and offering license opportunities for their new, patented Martensitic Stainless Steel tubing fabrication as well as stamped and shelled structures/components.

KVA Stainless has developed a portfolio of patents and proprietary technology for forming lightweight, high-strength, structural components for transportation vehicles using martensitic stainless steel alloys. These technologies contribute to the direct reduction in manufacturing costs relative to the implementation of conventional lightweighting methods and materials – for stamped, welded or tubular components.

Automakers are looking for ways to make vehicles lighter and yet safer; as a result, several new materials such as carbon fiber, aluminum, magnesium, titanium and thermoplastics have been introduced to the industry. Making cars and trucks lighter helps increase fuel economy, and making them safer reduces fatalities caused by serious collisions.

KVA Stainless believes that the next material should be martensitic stainless steel.

KVA Stainless has spent years testing and developing patented technology to produce stamped structural components as well as welded shapes for automobiles and trucks with characteristics that are strong and lightweight – yet, they can be produced at low costs. KVA's technology focuses on manufacturing original equipment and aftermarket automotive structural members such as vehicle pillars, sub-frames, cross beams, frame rails, frame brackets, roof rails, seat frames, seat rails, door beams, bumper beams, control arms, instrument panel reinforcements, running boards, roll-bars, tow hooks, bumper hitches, roof racks and numerous other applications. In addition to stamped structures, tube-based components can be fabricated with KVA's seam welded tubing technology: including fuel injection components, hydraulic lines, interior seat frames, exhaust systems, side steps, and roof railings.

Vehicle designers and manufacturers are trying to reduce the overall body mass of vehicle to improve fuel economy by developing structural members and components that are lightweight and of sufficient strength and durability to meet automotive safety requirements. In addition, automotive structural members must be able to contend with harsh environmental conditions, and thus must be corrosion and wear resistant.

In cost-sensitive applications such as automobiles, conventional engineering materials force a trade-off between cost and performance: measured by fuel efficiency, safety, and/or durability. Consequently, the typical vehicle tends to have a frame that is too heavy. A heavy frame requires a more powerful engine, which leads to higher fuel consumption and higher emissions. Having a more powerful propulsion system increases the manufacturing costs, uses more material, requires more energy to produce, which increases the emissions in the manufacturg process and necessitates an even heavier frame to support itself. Conversely, a lightweight, weak frame compromises the durability of the vehicle and the safety of its occupants.

Present day automotive structural members are still undesirably heavy – or – expensive to manufacture. The automotive industry has recently introduced new alloys into automotive structures to improve strength in an effort to reduce weight. Furthermore, complicated and expensive coatings and heat treatments have been introduced to improve the characteristics of corrosion resistance, hardness, tensile strength, and toughness. When alternative materials are used to perform lightweighting, studies have found that on average, weight reduction would cost $2 to $3.50 per kg of weight saved (Bandivadekar, 2008).

The aforementioned attempts at manufacturing lightweight structural automotive components still suffer from various drawbacks. For example, prior manufacturing processes are either too expensive or produce automotive structural members having characteristics which are less than desirable such as a lack of strength, durability, corrosion resistance, etc. Structural materials are currently available in a broad range of strength-to-weight ratios, or specific strengths, but the cost of these materials generally increases disproportionately to their specific strengths. Carbon composites and titanium, for example, while being perhaps ten times stronger than mild steel for a given weight, are typically more than fifty times more expensive when used to bear a given load. Consequently, such high performance materials are typically used only in on small items or in applications where the high cost is justified, such as in aircraft.

Generally, automotive structural members are manufactured from non-air hardenable steels. A rare exception to this is boron-treated steel, which provides high strength after a hot-stamping forming process. In this process, parts are formed in a red-hot superplastic state, and cooled within the stamping dies to harden the material. However, the hot-stamping process equipment requires a substantial capital investment – and the resulting parts typically require scale removal and are no more corrosion resistant than mild steel.

Air hardenable martensitic stainless steels are extremely affordable and have exceptionally strength, particularly compared to metals such as aluminum and even titanium. Experimentation with air hardenable stainless steel for automotive structural applications appears to have never been attempted due to the paradigm shift in thinking required to produce a high-strength automotive part. Historically, high-strength automotive applications relied on the evolutionary approach of forming ferrous alloy strip, in its final metallurgical microstructure, using successively higher strength steels as the raw material until either the strength targets were met or the part could not be formed due to the material's limitations.

Air hardening steels were first commercially developed for use in cutlery for their high hardness and excellent wear resistance. Common air hardenable steels include martensitic stainless steels.

Air hardenable martensitic stainless steels possess a relatively high carbon and low chromium content compared to other stainless steels. Additionally, little to no nickel is present, keeping material cost and volatility low relative to higher alloyed stainless grades. According to American Iron and Steel Institute (AISI) standard definitions, standard air hardenable martensitic stainless steels types include 403, 410, 414, 416, 416Se, 420, 420F, 422, 431, and 440A-C.

The relatively high carbon content compared to other stainless steels results in steel with the ability to harden via heat treatment to a high strength condition. Good corrosion resistance is obtained due to the protective chromium oxide layer that forms on the surface. Unfortunately, the high carbon and chromium has historically presented difficulties related to brittleness and cracking in welding, and accordingly martensitic stainless steel has been primarily used for cutting tools, surgical instruments, valve seats, and shears. Non-stainless air hardenable steels, which contain very high levels of carbon to allow the formation of a martensitic microstructure upon quenching, also present difficulties related to brittleness and cracking upon high-speed welding.

This ongoing lack of a strong and lightweight - yet low cost - automotive structural material is a main hindrance to the development of economically viable low emissions vehicles that can compare in performance, safety, comfort, and price to those powered by the typical internal combustion power system.

Thus, rather than resort to the use of expensive alloys, it would be beneficial to use KVA's patented technology to reduce manufacturing costs, enabling automotive structual members to be lightweight, high-strength, and corrosion resistant.

Ideal automotive applications for KVA Stainless processed martensitic stainless steel include:

• Removable Chassis Components (bumper beams, frame crossmembers, suspension control arms, subframes, etc.)
• Safety/Intrusion Management Components (side impact beams, roof bows, roof rails, B-pillars, etc.)
• Entire Chassis Frame Rails
• Fuel/Hydraulic Lines
• Fuel Injection Rails
• Exhaust System Components and Tubing
• Vehicle Seat Frames and Supports
• Vehicle accessories (tow hooks, racks, running boards, etc.)

Here are some of the products which have benefitted from KVA Stainless Martensitic Stainless Steel Technology:

KVA Stainless - Applications - KVA Stainless Steel Bicycle Tubing

KVA Stainless processed martensitic stainless steel tubing is ideally suited for use in high-performance bicycle frame applications.

• Heat-treated to ultra-high strength: tensile strength > 200 ksi (1400 MPa)
• Air-hardening alloy, yet easy to fabricate (38-42 Rockwell C hardness)
• Best suited for silver-brazed or TIG welded construction
• "Feel of steel" - plus corrosion resistance gives excellent ride quality and durability
• Precision Made in U.S.A.

After years of engineering and development, KVA Stainless is introducing its new, patented, custom-made stainless steel bicycle tubing called MS²® for high-performance bicycle frame applications.

Already proven by KVA Stainless in other industries, patented KVA martensitic stainless structural tubing can now be integrated into high performance bicycle frames to reduce weight, increase strength and stiffness, at a significant cost decreases over competitive materials. KVA Stainless controlled atmosphere thermal processing ensures consistent, high-quality tubing.

MS²® is an air-hardenable, martensitic stainless steel with amazing tensile strength > 200 ksi (1400 Mpa) which means it’s twice as strong as titanium with a frame weight comparable to high-end aluminum. The tubing has excellent corrosion-resistance, with elongation > 14% and a hardness ~ 38-42 HRC.

MS²® tubing is made in the U.S.A. from first quality domestic stainless steel alloys using the most modern forming, welding and precision thermal processing technology available to produce custom-made tubing; including variable wall thickness known as "butted" tubes.

You should expect excellent ride characteristics with outstanding durability and toughness from our new MS²® bicycle tubing. Excellent mechanical properties, including specific strength and stiffness, toughness and fatigue performance, can be achieved using MS²® tubing in place of other materials.

Ideal applications include silver brazed lugged construction and TIG welded bicycle frames.

Ed McCrink, the founder of KVA Stainless set up Hi-Temp, Inc. in 1953 and grew the company into one of the largest thermal processors of martensitic stainless steels in the United States. Successful with this venture, Mr. McCrink sold Hi-Temp in the 1970s and, with an entrepreneurial spirit, moved on to a number of different ventures. But Mr. McCrink couldn't forget about martensitic stainless steel. Mr. McCrink wondered why people weren't using this material in structural applications. Years after he sold the company, he came back to his roots of metallurgy, and he wanted to introduce the high strength features and benefits of martensitic stainless steel to different industries.

Working with a couple of engineers and metallurgists, Mr. McCrink developed a way to take flat sheets of martensitic stainless steel and transform them into tubes. Rolling the sheet to create the tube was never the hard part, welding a seam in martensitic steel so the tube became one solid structure or homogenous was always the issue. After years of engineering and testing, Mr. McCrink found a method to prevent the inherent cracking and weakness when a stainless steel tube is seam welded.

The resulting stainless tube is light and strong, and not nearly as expensive to produce as a seamless tube when compared to other stainless steel alloys or other metals, including titanium.

Bicycle Frame Materials

Strength, Safety, and Weight

In the hierarchy of cycling needs, cyclists care about weight, the feel of the ride, strength, and price.

Weight has been hyped in the media to the point that manufacturers are creating frames that are just one bad bump away from disaster. If you have not seen the results of failed forks and handlebars, try Googling "broken fork." It's not a pretty picture. The number of failures in high-end forks and frames is astounding, all because manufacturers feel pressure to defy the laws of physics with lighter and lighter forks and frames.

Safety is defined not just by the durability of a part, but also by the warnings the rider receives before component failure. A part that bends before it breaks is safer than one that snaps suddenly. Material strength equals safety, but what kind of strength?

Strength is measured in several ways, and it pays to consider all of them:

Impact Strength denotes how much concussive energy a component can absorb in a single blow without failing. Impact strength can be tested in a laboratory, but as a practical matter in cycling it is irrelevant. That’s because a severe impact will dislodge a rider long before it threatens the integrity of a frame or fork. Once the rider is down, the state of the part is meaningless.

Fatigue Strength is a measure of how well a material withstands repeated stress cycles. Fatigue strength is critical for a bicycle, since the rider constantly flexes a frame by pushing the pedals and pulling on the handlebars. Aluminum has the least fatigue strength among popular framebuilding materials. Steel, and Stainless Steel, by contrast, has the best... even exceeding that of titanium alloys. It can flex an infinite number of times below its "endurance limit" - a stress threshold for which no amount of cyclic loading will cause failure. This stress level is never approached simply by cycling on a properly designed and built steel (and stainless steel) frame.

Material (Fracture) Toughness is the feature of a material that describes its ability to prevent a nick from turning into a crack, and a crack from turning into a break. Toughness is another area where steel and Stainless Steel far outperforms aluminum, carbon fiber, and titanium. Think about it: When was the last time you saw carbon fiber nails, or aluminum rebar? Never.

Ultimate Tensile Strength (UTS) is a widely cited measurement of material strength. UTS is measured by pulling apart a test coupon made with material of a specific thickness and length. The UTS of tubing is not insignificant, but it is vastly overrated as a measurement of the strength. Bicycle frames are not torn in half, nor do they fail because of uniaxial tension. Other factors, such as fatigue, cracking, and impact will cause a frame to fail long before UTS becomes a factor. Glass has extremely high UTS because it is difficult to pull apart, but a glass bicycle would not last long on a mountain trail or even a street. All the materials used in traditional bicycle tubing have sufficient UTS to be safe.

The feature most critical to rider safety is its mode of failure. That is, how long the material will support the rider after its integrity has been breached by a crack, a hole, a dent, or even a deep scratch. A rapid–even instantaneous–failure is known as a catastrophic failure. Catastrophic failure leads to injury.

Of the most common materials used in bike frames today, carbon fiber has the highest rate of catastrophic failure. Steel and Stainless Steel has the lowest rate of catastrophic failure. When steel fails, it fails slowly. In a sport where speed is the name of the game, failure is the one area where it's good to be slow. Real slow.

Metals responds to force by bending, denting, and even stretching (elongation), not by snapping and shattering. The slow rate of failure provides time for the rider to pick up warning signals, feeling something is wrong prior to the failure of a component, preventing injury.

Of secondary importance, but worth considering, is reparability. The old auto body shop adage is “metal has memory.” Steel can be repaired more completely and more easily than other materials can.

Comparing frame materials that are new is one thing, but what about frame materials that have aged? Different materials age in different ways. Environmental factors such as temperature, humidity, air salinity, ozone, and ultraviolet radiation all affect framing material. Life is a laboratory that is constantly fizzing.

In the harsh world of chemical change, metals outlast plastics and carbon fiber. A weak point of carbon fiber is in the resins that hold the carbon fiber layers together. These resins are prone to degradation when exposed to ultraviolet light from the sun.

However, metals are not exempt from environmental degradation. Typical bicycle tubeset aluminum alloys, for example, "age" naturally to higher strengths over an extended period of time. While a stronger tube may appear better, the microstructural change robs the material of its ductility and can cause premature brittle failure – especially around welded joints.

The phrase "environmental degradation" often evokes images of metallic corrosion–rusted wheel wells, corroded hinges, and leaky watering cans. Rust (a term reserved for the corrosion byproduct of steel reacting with oxygen) actually builds up a protective layer that protects the underlying steel against further environmental damage. That is why it is not uncommon in some parts of the world to see 20-, 30-, even 40-year-old rust-covered steel-framed bikes still in use. Of course, the thicker the steel, the less vulnerable it is to failure due to corrosion. Super-thin, 0.35mm steel tube frames are more vulnerable to damage from rust than thicker-walled tubes are. However, diligent care with anti-rust, protective film sprays such as FrameSaver, Boesheild T9, and LPS can prevent corrosion. If you prefer old-school solutions, try coating the steel frame with linseed oil or automotive waxes. Alternatively, Stainless Steel tubing offers corrosion resistance as well as high strength. A "passive layer" of adherent chromium oxide forms to protect stainless steel from further environmental degradation. Under most conditions, this protective layer is self healing – if scratched new chromium oxide layer will form nearly instantaneously.

Another important, but rarely discussed, aspect of frame material is defect tolerance. No one wants to admit that materials have defects, but they do. It is impossible to manufacture quantities of anything without occasional defects. Even in the white-coated, "dust-free" environments, defects creep into materials. That’s why everyone from rocket engineers to computer chip manufacturers build defect tolerance and safety factors into their designs. Bicycle manufacturers should, too. The important thing to know is how an unseen defect will affect the strength and integrity of the material. A material that is more defect-tolerant is less likely to fail. Steel and Stainless Steel are materials that are highly defect-tolerant, due to their high toughness and durability. Carbon fiber is the least defect-tolerant of all materials used in the making of bicycle frames.

Shock absorption is another material quality that makes for a safer and smoother ride. The physics of shock absorption are as old as Newton's laws of motion: Every action causes and equal and opposite reaction. A shock is absorbed by motion–compression, deflection, or both, and dissipated within the material. Something has to give.

The idea that a shock can be absorbed without motion is a myth. One marketing claim is that carbon fiber forks absorb shocks well, creating a smoother, more comfortable ride. It sounds promising, but it conflicts with basic physics. Carbon fiber is very stiff, so there is relatively little movement to absorb the shock. Metal absorbs some shock through compression and deflection, but only suspension forks truly absorb shocks, because they move. Otherwise, the best way to create a smoother ride is to deflate your tires and lighten up on your grip.

Vibration damping is a phrase heard a lot in the cycling world, but its importance is exaggerated. The term refers to a material's tendency to absorb and dissipate vibrations after some force causes it to start vibrating. Wind chimes produce sustained vibration, pleasing their owners but often annoying the neighbors. Vibration is the result of high-frequency flex or applied loads. The flex of a component is influenced by the material it is made with, its size, and its shape.

The entire discussion of vibration damping is somewhat academic when it comes to cycling, however, since bicycle parts are not suspended in the air like a tuning fork. A bicycle is composed of multiple components, including the frame, the fork, rubber tires. Most importantly, a bicycle is in contact with the ground and it supports a rider whose body absorbs vibrations of the frame. Having said this, the bulk material properties can be used to generalize the "feel" of a frame and its tendency to damp vibrations. Carbon fiber, being very stiff (with a high elastic modulus) is considered by many to be harsh, transmitting every bump and ripple directly to the rider – causing fatigue and discomfort after long rides. Aluminum, magnesium and even titanium have been described as "soft and mushy", with their lower elastic modulus and stiffness. Riders enjoy the feel of steel and stainless steel – the resiliency and liveliness of the material is without comparison.

Physical comfort on a bicycle is influenced by several factors, of which frame materials is the least important. The height of the handlebars, the distance from the seat to the pedals, and the air pressure in the tires all contribute more to a comfortable ride than the frame materials do. Raise the handlebars, move the seat back, and decrease tire pressure for greater comfort. Remember to relax your body and lighten your grip, too.

Comfort is as much psychological as it is physical. A bike may fit your body perfectly, but if your mind is unsettled about it, it won't feel right. For example, a woman who grew up with an open "girls" frame might not ever feel comfortable on a standard diamond style frame. Similarly, hardcore racers who curled their 6-foot bodies around a 56cm frame might never get used to a 62cm frame, even if it is a better fit for their size. The same goes for frame materials. Steel affords the maximum strength and safety, but some people resist it on psychological grounds, mainly because of perceived weight penalties.

Consider this: The weight of the bicycle frame makes up only ¼ of the overall weight of a bicycle, and the bicycle is only 1/10 of the overall weight with a rider in place. In other words, frame weight is only 1/40 or 2.5 percent of the overall weight. So shaving a pound off the frame weight will change your overall weight by less than one percent. You can double that weight change simply by losing two pounds of body weight.

Many people believe engineering is more important than materials, but that is not entirely true. The differences in material–especially failure modes–can increase safety and reduce injuries. Steel and stainless steel frames may sound out of date, but for strength, safety, reparability, durability, and aesthetic beauty, nothing beats steel or Stainless Steel. Enjoy the Feel of Steel^TM

Contact us with inquiries.

Shell and Tube Heat Exchangers

KVA Stainless is selling tubing and offering license opportunities for their new, patented Martensitic Stainless Steel tubing for heat exchanger applications. Benefits include increased performance through increased thermal conductivity and heat transfer, and reduced costs with 410 Martensitic Stainless Steel tubing.

410 Stainless Steel tubing offers significantly increased heat transfer and strengths, as well as a reduction in thermal expansion, when compared to typical austenitic Stainless Steel tubing grades such as 316L.

Thermal conductivity of 410 Stainless Steel tubing is 53% BETTER at the same wall thickness than 316L tubing (410 k=24.9 W/m-K; 316L k=16.3 W/m-K @ 100 degrees centigrade). Engineers will appreciate the ability to reduce the wall thickness of 410 Stainless Steel within their heat exchanger designs, while still maintaining burst pressure requirements. Overall heat transfer can be improved an additional 400% in hardened 410 designs relative to conventional heavy-wall 316L heat exchangers rated for identical maximum pressures.

Thermal stresses are also reduced as 410 has a Coefficient of Thermal Expansion (CTE = 9.9 um/m/K) 38% less than 316L (CTE = 15.9 um/m/K). As a result, thermal fatigue stresses are reduced and product durability is increased.

The introduction of 410 Martensitic Stainless Steel for the fabrication of heat exchanger tubing offers higher strength, increased hardness and wear resistance, as well as a lower cost alternative to Ferritic series Stainless Steel alloys, which include 410S.

The hardened strength of 410 Martensitic Stainless Steel is twice that of 410S. Heat exchanger tubing made out of 410 Stainless Steel will allow for thinner walled material to carry the same pressures, increasing heat transfer and making the heat exchanger much more effective. Using less material also reduces overall costs per tube, heat exchanger fabrication and shipping costs.

Heat Exchanger Basics:

A shell and tube heat exchanger is just one type of heat exchanger design. It is suited for higher-pressure applications and markets such as: dairy, brewing, beverage, food processing, agriculture, pharmaceutical, bioprocessing, petroleum, petrochemical, pulp & paper, and power & energy.

As its name implies, this type of heat exchanger consists of an outer, elongated shell (large pressure vessel or housing) with a bundle of smaller diameter tubes located inside the shell housing. One type of fluid runs through the smaller diameter tubes, and another fluid flows over the tubes (throughout the shell) to transfer heat between the two fluids. The set of tubes is called a tube bundle, and may be composed of several types of tubes; round, longitudinally finned, etc. depending on the particular application and fluids involved.

There may be variations on the shell and tube design. Typically, the ends of each tube are connected to plenums or water boxes through holes in the tubesheets. The tubes may be straight or bent in the shape of a U, which are called U-tubes.

The selection of material for tubing is extremely important. To be able to transfer heat well, the tube material should have good thermal conductivity. Because heat is transferred from a hot to a cold side through tubes, there is a temperature difference through the width of the tubes. Because of the tendency of the tube material to thermally expand differently at various temperatures, thermal stresses occur during operation. This is an addition to any stress from high pressures from the fluids themselves. The tube material also should be compatible with both the shell and tube side fluids for long periods under the operating conditions (temperatures, pressure, pH, etc.) to minimize deterioration such as corrosion. All of these requirements call for careful selection of strong, thermal conductive, corrosion-resistant, high-quality tube materials. Typical metals used in the manufacturing of heat exchanger tubing include: carbon steel, stainless steel (austenitic, duplex, ferritic, precipitation-hardenable, martensitic), aluminum, copper alloy, non-ferrous copper alloy, Inconel, nickel, Hastelloy, tantalum, niobium, zirconium, and titanium.

Renewable Energy

Manufacturers and providers of renewable energy products, services and solutions consistently strive to improve design and performance characteristics in an effort to gain a competitive edge. With the aim of continually enhancing their value proposition, manufacturers and providers demand tubing, components, and assemblies that are lighter, stronger, more durable and corrosion-resistant compared to traditional alloys. With cost an ever increasing concern, they are also looking for proven alternatives to expensive specialty alloys.

KVA Stainless is committed to helping renewable energy firms economically achieve a distinct competitive advantage in the design, manufacturing and marketing of their products. Backing up this customer-focused commitment is a tireless emphasis on driving the creation and development of innovative solutions that leverage the differentiating performance characteristics and life-cycle cost advantages of KVA processed MSS.

Select applications:

• Strong yet lightweight structural components, assemblies and weldments
• Structural columns
• Lattice tower systems
• PV framing and mounting systems
• PV and Solar Hot Water fluid transfer tubing
• Ladders/railings
• Lightweight and corrosion resistant fittings
• Heliostat Frames (for tracking and stationary solar power modules and mirrors)
• and much more...

Please contact us for information regarding your specific needs. Our seasoned engineering team is committed to identifying ways that KVA Stainless technology can be used to provide you with a sustainable advantage in the competitive renewable energy arena.

Transport, Gas and Oil Production/Pipelines

KVA Martensitic Stainless Steel (MSS) tube and pipe are low-cost, high performance substitutes for traditional carbon steel, 12Cr and 13Cr materials. KVA MSS is the patented, original and only fully martensitic, high toughness seam-welded pipe, offering unsurpassed tensile strength, hardness and wear resistance as compared to common low carbon corrosion resistant modifications such as:

• Duracorr® (UNS S41003)
• Cromgard® (UNS S41003)
• 3Cr12
• 410S (UNS S41008)
• 409 (UNS S40920)
• 12Cr
• 13Cr

¹Duracorr® is a regisitered trademark of ArcelorMittal
²Cromgard® is a regisitered trademark of American Utility Metals

KVA Martensitic Stainless Steel pipes can be produced in standard sizes up to 36" and wall thicknesses up to 0.500". Non-standard sizes upon request.

KVA longitudinal seam-welded MSS can be produced fully hardened, fully annealed, or anywhere in between, at substantial cost savings over seamless 410 or 420 pipe! Typical properties of KVA MSS pipe:

Hardened:
Yield strength: 160 ksi (1100 MPa)
Ultimate tensile strength: 205 ksi (1400 MPa)
Hardness: 370-390 Brinell (40-42C Rockwell )
Elongation: 8-9%

Annealed:
Yield strength: 45 ksi (300 MPa)
Ultimate tensile strength: 80 ksi (530 MPa)
Hardness: 130 Brinell (80B Rockwell )
Elongation: 30+%

The introduction of KVA Martensitic Stainless Steel for the transport, oil and gas pipelines is ideally suited for mildly corrosive, abrasive media applications such as:

• Oil sands
• Slurry pipelines
• Coal transport

The abrasion resistance of hardened KVA MSS tube and pipe is unmatched – maximizing durability, reliability and reducing erosion-corrosion failures. KVA Martensitic Stainless Tubing can be produced with chromium content ranging from 11.5wt% to 16wt%, maximizing production and service life while minimizing cost.

KVA MSS can be produced to the following specifications:

• ASTM A268: Standard Specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service
• ASTM A999: Standard Specification for General Requirements for Alloy and Stainless Steel Pipe
• API-5LC: Specification for CRA Line Pipe

Please contact us to discuss your particular application with KVA. KVA can recommend the appropriate welding procedure for field welding MSS without cracking or embrittlement for welding methods such as:

Gas Tungsten Arc Welding (GTAW/TIG), Gas Metal Arc Welding (GMAW/MIG), Shielded Metal Arc Welding (SMAW/"stick"), Submerged Arc Welding (SAW), Electric Resistance Welding (ERW) and Laser/Hybrid Laser-Assist Welding.