Sunday, November 5, 2017

Hard Facing- What Is It?

Today I would like to explore a market that peaked in the 1960s. Like today, two of the major problems causing replacement of parts include wear and corrosion or combinations of the two. In the sixties, the major materials available were mild and low alloy steels. Stainless steels were just starting to attain popularity. However, there were many applications where the steels available were incapable of sustaining wear or corrosion in environments such as  drilling in mines, off shore applications for drilling rigs aircraft repair and shaping of glass bottles to hold liquids.Yes, silicon is abrasive and is the major constituent of most glass. Yes, glass bottles were a major market then because plastics were not yet replacing the cheap glass bottles. However, silicon is abrasive, and therefore something better was needed to extend the life of the part through improved protection of the surfaces used in these applications.
Engineers at small companies in those days, like Metco and Wall Colmonoy, recognized these differences between metals and glass. Therefore it wasn't long before someone decided that if you alloyed metals with silicon and boron  you could create a series of alloys tha,t when heated, became cherry red and did not melt immediately, but slicked up and remained that way for a period of time until the coating became fluid enough to melt and drip from the steel. Furthermore if you alloyed the powder or the wire with elements such as nickel and chromium, and other additives, such as particles of tungsten carbide, you had a surface that was corrosion resistant and had hard wear resistant carbides, borides and nitrides distributed within to provide surfaces that were significantly resistant to corrosion and wear.
Therefore a process developed whereby powders were atomized to these basic compositions with varying amounts of the constituents described that, when fused,  deposits ranging from 40 to 60 HRC hardness protected the surface from wear and corrosion. Tungsten carbide powder was admixed in a fine particle size distribution to further enhance the surface against abrasion.These powders were poured into a canister contained within the spray gun or within an external container, depending on the design of the spray gun. An acetylene oxygen fuel was then activated and the powder introduced within the fuel where it was heated to a temperature that was sufficiently warm to cause the powder to be plastic so that when it emerged from the gun as a spray, it deposited on the substrate as what is known as a splat. This porous deposit was then further heated with a welding torch or placed in a furnace at an appropriate temperature to fuse, similar to a glass with minute porosity. Unfortunately the bond with the substrate is not the most desirable, Therefore the fused coatings had a tendency to spall or flake from the surface, depending on the application, and replaced to renew adequate protection of the substrate. Also much depended on the skill of the operator in making the deposit and fusing it.
Today more ways to deposit coatings on surfaces have emerged. Plasma Spraying, which employs higher temperatures approaching those of the sun,  capable of providing any coating that can be engineered, is available.Also, furnace deposited and diffused coatings are possible that compete with hard faced coatings and do not have the weak interface associated with spalling and fracture that are common with hard faced coatings but have a transitional interface that blends to the microstructure of the alloy substrate.
Moyer, owner of MagnaTech was one of the first people to improvise Hoeganaes hard facing powders to supply most of the hard facing gun manufacturers. More recently he has developed a process that deposits an atomic reactant on the surface of the substrate that reacts with the alloying elements within the substrate to provide a hard wear, corrosion resistant, surface that can compete with hard facing processes in existence today. Many say that like the one horse buggy that hard facing is becoming passe'. However, recently MagnaTech has been provided with an opportunity to quality control plasma sprayed chromium carbide coatings. We look forward to the emerging of this opportunity.

Sunday, October 29, 2017

Big Brake Problem

Just finished a proposal to the Marines. You know, the world more and more thinks smaller is better. However, it is not often that you hear this coming from a Marine.In this case, there are many more people that think big. like Marines, and have the same concern. That is because there is an entire industry, including the Marine,s that has a big problem that involves big equipment.
In the case of the Marines, the problem is now critical for improved efficiency of operation of medium and heavy tactical vehicles that operate on five axles. The same problem exists with any off road or off shore equipment that exists for transporting large loads and operates in harsh environments, such as brackish or sea water. These liquids are corrosive and  the vehicles, when traversing them are moving at high speeds,  activate the beds and create slurries of liquid containing abrasive particles. These slurries intrude into open access areas within current brake systems, thereby causing corrosion from the reactive liquid and wear from the particles entrained within the fluid.Owing to the braking components weighing as much as 400 pounds, their life becomes limited , owing to the erosion and corrosion occurring during operation. Therefore life is unpredictable and inability to operate because of brake fade or failure,and inability to operate may occur at critical times when inability to function may result in disaster.
Therefore today there is focus on resolving this problem. The ideal solution would be first of all extension of predictable life and secondly, rapid replacement and restoration of the braking system of the unit to permit resumption of operation.
Corrosion and erosion are processes occurring at surfaces of the braking components. Therefore, if the surface of the component can be improved and improved quickly at the incidence of malfunction, then a major step has resolved the problem quickly, resulting in saved lives, expensive equipment and possibly a critical time when cost is extremely critical. Once the immediate problem of unpredictable function is resolved then modeling can result in improved design resulting in reduction in weight and additional savings in cost and efficiency.
MagnaTech has developed a process whereby the surface where corrosion and erosion occurs can be modified to improve the life of components experiencing the events described above. We have shown, in a different application, that the process has equaled or exceeded life of equipment through improvement of corrosive and erosive attack without experiencing brittle failure such as results from hardfaced surfaces. This additional protection results because our process uses the alloying elements within the brake components to combine with atomic deposited condensed gases at the surface to result in stable, non-reactive intermetallic compounds that transition to the microstructure of the alloy without impairment of properties required for efficient function of the component. Therefore, yes, erosion can occur and eventually will require replacement of the component. However, life will be predictable. Furthermore, we have teamed with another company to demonstrate that should incident of failure occur  at a critical time, in a hostile environment, repair is possible that can minimize the problem or save the day.If you believe that you have need for resolution of a similar problem, MagnaTech would delight in assisting you in resolution of this problem.

Monday, September 4, 2017

High Performance Materials for Nuclear Applications

High Performance Materials for Nuclear Applications

Today’s nuclear reactors are old.  They require long storage time for spent radioactive reactor fuel.  In addition,  extension of life for an additional twenty years will be expensive.
Generation IV nuclear reactors are in the concept stage of design. These nuclear reactors would have advantage over existing nuclear reactors in many aspects. One concept is the design of a reactor that can be constructed and placed on a flat bed for transport to remote sites or sites requiring less space and less isolation. These lighter weight, more efficient, safer reactors would make it possible to establish the reactor at sites such as a waste water area, where the water could be purified for public consumption, and generate electricity for additional usage. Similarly these transportable reactors could be small enough and safe to power large industrial plants, building complexes and even small cities, if coupled with additional similar reactors to supply the required capacity. In addition, the energy produced is clean, could possibly be used to produce clean fuels, and could reduce or eliminate fossil fuels that currently pollute the atmosphere..
            To render these smaller reactors cost effective and safe; these reactors must operate at higher temperatures . Estimated temperature required for the short term is 8500C and ultimately 10000C..Higher operating temperatures cause problems because current alloys are not capable of resisting corrosion, and approach limits of functional capability at these temperatures. In addition any material selected must comply with ASME Boiler and Pressure Vessel Code Section III Division V.
Inconel 617 is one of the alloys of interest because it can satisfy high temperature mechanical properties and be accepted within the confines of the Code. Actually it could serve as components of pumps used to remove heat generated by the reactor, and also in DRECS that  serve as reservoirs for storage of the salt, if the alloy had improved surface protection against harsh corrosive environments, such as molten salts, which are being considered  as coolants. Therefore a coating resistant to the corrosive liquid salts or coolant specified is a must. Thin coatings are available but are not being considered as a solution to the corrosion problem because they have been found to peel, spall, debind and scratch over the service life of the part. Therefore, coatings greater than 0.635 mm are being considered to provide the required elevated temperature corrosion resistance.
MagnaTech has developed a process that provides protective surfaces that resists abrasion, impact and also provides excellent corrosion resistance from salt water. Surfaces  were produced to protect stainless steel and low alloy steels to combat the conditions required of shoes of hook points of F-35 aircraft. There was no spalling, peeling, or debinding  that resulted from the various impact or abrasion tests administered to the surface modified alloys. This was because the process is one that deposits atoms of carbon and/or nitrogen on the activated surface of the substrate to react with elements alloyed within the surface of the steel to form stable carbides and nitrides that provides surfaces that have no interface with the steel matrix. In addition, surface grain boundaries consist of stable carbides and/or nitrides that prevent grain boundary sensitization, resulting in improved corrosion resistance of the alloy, in this case resistance to salt water. MagnaTech believes that the same mechanisms used for the application intended could be used to provide the required surface resistance from the high temperature corrodants transported in pumps  to cool the reactor and in DRECS used to store the coolant , probably liquid salt solutions.
Markets will not be established until the early 2020 s. If developed a huge market for this clean, transportable energy source will rapidly emerge..

Monday, July 3, 2017

A Smaller Electronic World

Summer and the Holidays are here. It is a time to slow down, just a little. However, at times like this I have the luxury of "what iffing". At such times, I reflect back to what the world seemed to be when I was a young engineer. Steel was the material of choice for good reason:  it was cheap, it was abundant, and it had the properties of strength and ductility.
Slowly but surely I watched as new elements began to fill the periodic table New, more exotic microscopes emerged that permitted us to observe topography, defects, and even determine phases and chemistry of these phases. Eventually we could strip atoms from surfaces and determine the composition and degradation of protective surfaces, atomic layer by atomic layer. Now equipment is available that permits us to even look within the atom itself. Thermodynamics became important, and for early designs such as cars and aircraft, stainless steels and superalloys emerged, permitting jet aircraft and space vehicles to become possible. Coatings were developed that protected vulnerable surfaces from oxidation, wear and shock. Processes and techniques were developed to shape and join components together to make more sturdy structures for sea worthiness, windmills and nuclear reactors for efficient electrical energy.
However, with the good comes the bad. As more and more of the resources available courtesy of Mother Nature were depleted and processes required for reclamation, purification, fabrication and operation increased, resources required to do these operations resulted in increased pollution of our environment. Therefore we found ourselves seeking alternate materials and processes that would reduce weight, improve efficiency, reduce cost and permit increasing opportunities to make things that were currently not possible.Weight became cost saving in material, time and labor. For example, in many applications, such as turbine blades, expensive superalloys, containing more expensive alloying elements. to provide high temperature properties such as creep resistance, and prevent more reactive corrosion from occurring at the higher temperatures of operation, limitation of usage resulted and expense became  burdensome for small gains in material properties.
To alleviate some of these problems, solutions were first pioneered again by the auto and the aircraft industry to further reduce weight by looking for new alloy systems that would have higher strength without sacrifice to ductility. Therefore more interest in titanium, aluminum and magnesium alloys. One way of accomplishing this is through powder metallurgy. It  is well known that different tools are available to improve strength of light alloys made from powders. The problem remains how to do this without limitation of ductility.Methods have been developed to atomize fine powders in atmospheres that protect surfaces from contamination, thereby improving densification when consolidated,  with improved ductility. New alloy systems are being developed to take advantage of the new processing of powders.In addition, there is new interest in producing more ductile composite powders and ceramics that may have high temperature strength with improved ductility. If this happens then space becomes the new world and transportation becomes faster, providing opportunities not realized to date.
Powders are not limited in the size of a part being produced. For instance, already possible are production of orthodontic devices to improve functions of the mouth. These devices are made possible by recently developed metal injection molding processes. Other medical devices, such as small stents, have served to improve human and animal life. These are small  parts. They are expensive, but they cannot be made by  currently developed procesess.
However, not so fast, because now new processing has emerged called advanced manufacturing, because it includes several current technology under development. Not only were processes required to produce new undeveloped powders with undefined properties but instruments, such as lasers and electron beam guns were required to deposit the powders in atomic layers quickly, where they are melted and built layer by layer from the smallest conceivable part to an auto body or even a nuclear reactor structural member. These developments are in progress currently. By use of the computer and robots, these structures can be made, small or large, atomic layer by atomic layer with no restriction of geometry. Therefore, thin parts with complex designs not possible before become reality. I could go on, because there is much more to come that is even more mind boggling.
The other buzz word of the day is modeling. This is a new term but an old concept. Back in the 1980s it was known as regression analysis and it came on because hand held computers became available. These permitted storage and saving of information.Today we have aging equipment and processes that have not been maximized for efficiency and precision. Today's technology requires improved efficiency, and in many cases, precision. Through examination of critical variables that could affect the properties, these known, established processes can be fine tuned to yield higher quality functioning parts. Alloy systems and processes can become more efficient, resulting in significant savings.Therefore many well known processes are undergoing modeling studies today to make improved parts at lower cost. Not a new thought--just made faster through use of the computer.
Therefore, to the young materials engineer just starting his or her career,, hang in there. This is still an exciting world with much still to be accomplished. You are that young engineer as I was in days of yore, watching a steel industry and a transportation industry grow. Hey, it just ain't over til the fat lady sings.

Friday, May 19, 2017

Aging Equipment

Current aircraft are designed to last for 40 years. In some cases,the life of these aircraft have been extended well over this time period, and ways to extend life further are being considered. In the case of landing craft gear on the plane, this equipment encounters the most stressful conditions.  For instance,if the plane is to accomplish its mission, it must take off and land each time. Therefore, it is difficult to truly determine the pressurization cycles sustained.
In the case of landing gears, the plane lands at approximately 180 mi/hr. Depending on the weight of the aircraft, you can understand that the conditions for stress are high for each cycle of landing and take-off sustained. Therefore as the number of landings sustained increase the effect of any defect present in the material becomes the initiation for a fatigue crack. Fatigue starts normally at the surface. The effects increase with stress  associated with repeated landings. As the number of cycles of landing increase, so to does the stress or work hardening increase. If a defect is present, then when the stress increases to a certain level  a small crack, known as a microcrack occurs at the defect. Once micro- fracture relieves the sustained stress, then the microcrack is arrested and the sequence of events begins once more, until the stress level is such that further crack extension occurs. This concept is known as fatigue. Therefore these events will continue until the remaining non-stressed area cannot support the forces or stresses sustained in landing. At this point catastrophic failure occurs, resulting in severe danger to the pilot and the expensive aircraft.
In the present sense the flight crew watches progress. When defects in excess of about 0.040 inch are observed the landing gear components are inspected to determine the extent of the damage. Unfortunately, records can become lost and errors or misinformation can result.
The process used for manufacturing these critical parts begins with the manufacture of the steel selected for the component. All steels have defects called inclusions, porosity and perhaps surface corrosion. These defect can be extremely small and difficult to detect. Currently these defects are not often detected because of their small size. Techniques are currently available to permit detection of inclusions 0.040 in size. However, current efforts are attempting to designate inclusions less than 0.010 inch and as small as 0.001 inch. These would be difficult to accomlish using current maintenance.
Therefore a study and record of the total processing conditions becomes of importance. Once the steel is obtained and certified regarding defect content,  machining of the component begins. Generally this is under control, but often defects can occur from poor machining practice. Once the component is machined, then the part must be heat treated to achieve the proper core properties to sustain the stresses that will occur in service. This process to can result in the formation of microcracks, ultimately resulting in fatigue.Finally there is cause for concern of corrosion resulting from operation in harsh environments. Therefore,the parts are normally chrome plated  after heat treatment. This process is quite often a severe problem because of the different expansion rates between the steel and the chrome plate. Therefore the possibility of defects sustained in processing become the limiting factor in the life cycle of the component. MagnaTech intends to propose solutions to identify causes and minimization of these defects in a proposal currently being prepared. MagnaTech is looking for prospective partners to co-operate in resolution or minimization of the current problem.

Saturday, March 18, 2017

A Changing Materials World

A new President and a change in direction for manufacturing in this country. The outgoing flow of manufacturing  from the country has been stemmed and now there is an influx of manufacturing back into the country. In addition, the direction of attention of available resources, both human and material are now starting to be driven in a different direction, both as an effect of policy change as well as obsolescence of things that should have been maintained properly or that merely have reached the end of their life cycle.At any rate the change bodes new challenges and requires different assets to accomplish the job.
To regress, I entered the materials world as a young engineer in the 1950s. At that time, it was a different world. Most of the periodic table was empty at that point. Steel was the material of choice because of its abundance, its cost, and a foundation of an industry ready to produce it, shape it, heat treat it for desired properties and finish it into shapes required for a growing list of applications. Plastics were used for toys and even then, a now-banned lead was used to cast toys. Aluminum was light and therefore it was ideal for an emerging aircraft industry. Because of cost of producing it, expense of material was too great for anything else. Not many remember that the first aluminum utensils were for the French King on his birthday. The other materials that were used were copper alloys, brasses and bronzes, and that was about it.
However, today all of this has changed. The periodic table is now full. From a few basic steels, an extensive Table, listing steels for many different applications, is available and more steels are constantly being added. These include steels for structural applications, chromium steels for hot working, such as dies for extrusion and forging, tool steels, a growing list of stainless steels for corrosion resistance, specialty steels, and now micro-alloyed steels. In addition, because of need for lightness, aluminum and titanium alloys are now under development. Nickel, cobalt and iron superalloys are available for today's aircraft requiring increased payloads and designed to fly at higher altitudes. Chromium and refractory alloys are now starting to emerge for space applications requiring even higher temperature and corrosion resistance.  Sounds exciting? well yes, but with the loss of manufacturing to outsourcing we have a problem of skilled labor. This includes people that use their hands as well as their brains. In other words, with the influx of returning industry and a change in priorities for manufacture, there is now becoming a shortage of people that were machinists, die makers, welders and other skills requiring hands-on skill. These people were developed in special schools called Trade Schools. However, due to over supply, these schools have largely disappeared and to make matters worse the pool of qualified machinists and welders, etc, is aging at a time where more are needed. Robots are replacements, in some cases, however, we now start limiting available jobs, and that is another problem.
Therefore, where are we going today? Well certainly we need people to man industry returning to the country. In addition, look at the national statistics of our transportation system. In our area, trains ordered by the transit system have faulty welds and they require repair. Track for railroads is old and new technology is required to improve travel by train. Bridges are all aging and are in desperate need of repair or replacement. Newer improved roadways are needed. In addition, our nuclear reactors are also aging and in need of costly repairs or replacement. These reactors provide the cleanest energy that we have to date. They also hold the promise of production of cheap hydrogen to replace environmentally unfriendly hydrocarbon fuels. New energy efficient housing is required. All of this requires laborers with hands on experience. Therefore, we predict that in the near future, more emphasis will be placed on re-establishment of trade schools. These will become alternatives to the complex issues now emerging at our Universities.
Yes, a changing world, some of it back to the basics. However, there is always a need for new technology, with some of the problems that it brings. Except for offshore rigs, the ocean remains largely unexplored and it is three quarters of the earths surface. In addition we are fast approaching the capability of faster travel and even unmanned  space travel. Even colonization of unknown worlds is becoming a possibility. My kids when they were young used to say," are we there yet."? I'm afraid the answer is still no. There are a lot of challenges in the next few years. Change is always with us and as long as brain power and skill of hand power is required, it remains a good and an exciting thing. I look forward to the next few years as we begin building our infrastructure.

Saturday, February 4, 2017

Expansion In Magnetic Technology

MagnaTech has been active in development of soft magnetic alloys since the 1980s. At that time Hoganas Sweden developed a powder metallurgy alloy that contained phosphorus. However, Hoganas did not develop the alloy for magnetic applications, but because it contributed solid solution strengthening to iron.
At this time, in America, General Motors was developing a new motor concept for automotive engines. They therefore approached Hoeganaes, Riverton for assistance in making this part. However, General Motors was familiar with silicon steel,  not powder metallurgy. Therefore we convinced GM  that this new phosphorus iron  I was developing for magnetic relays would do the job for their application. Therefore, the phosphorus irons were developed for magnetic applications and a new market for powder metallurgy technology was born. Later on, powder metallurgy ferritic stainless steels were developed for applications that sacrificed some magnetic performance for improved corrosion resistance.
Since then MagnaTech has become more active in consulting and testing of laminated magnetic alloys, such as molybdenum permalloy and iron cobalt alloys. MagnaTech has used only ASTM Specification BA596 (Equivalent ASTM A773) for testing these materials, and continues to do so. However there is now a demand for determinimg core loss of these materials for AC applications. MagnaTech is considering modifying their test equipment to also accomplish this testing in accordance with ASTM A927.
In addition to the above, the alloys of interest require carefully controlled heat treatment to perform to the level expected of the device.MagnaTech is interested in developing qualified sources to provide this service.
MagnaTech has been active both in research and development of heat treatment of these materials as well as in development of procedures for the testing of these magnetic materials that require properties for critical performance. If your company has need for these services please contact MagnaTech and we will quickly respond to your requirements.