As descendants of “handy man (Homo habilis)”, we have created civilization by adjusting to and, at times, challenging the rough and ever-changing environment. Megacities with cars moving through a cluster of high-rise buildings, trains crossing long bridges, and airplanes flying, leaving white streak in the sky, show typical features of modern civilization. The use and advancement of tools led to the increase in industrial productivity, and, coincided with the physical expansion of the society, brought about the development of human civilization. Materials, which have played a fundamental role in increasing the efficiency of tools, are becoming a standard for determining the different stages of development of a civilization.

Tools made from materials that are easily found in nature, such as wood, straw, and stones can be commonly found. Objects and tools made from metal are also or even more commonly found. The use of metal in making tools began later than other materials as it is rather complex and requires elaborate use of fire to make metal from raw materials.

However, metals have become the most important material in today’s industrial society due to their strength and formability. Among various metals, steel has played a leading role due to the availability of the natural resources and is highly formable after relatively simple adjustments. As such, the production and consumption of steel can be an indicator of the level of development of a country.

“Dislocation” Sets a New Course in Metallurgy

Metals are typically solids at room temperature. Think of toys that consist of small individual pieces to be assembled to form a single larger object. Many solids are formed by regular arrangements of symmetrical structures (e.g. a cube) made of atoms in an infinitely repeating pattern, filling a three dimensional space. This is known as crystal structure.

The level of force between the atoms in a metallic crystal is known to be weaker than the force in other solid forms. Also, a crystal structure typically contains crystallographic defects that do not conform to the regular arrangement. Among the defects, “dislocation” greatly influences the mechanical properties of the crystal structure.

In a dislocation, empty spaces between atoms create a long, straight line. Tapping, bending, or stretching the metal is a process in which the dislocation within the metal is created and rearranged. Because the level of interaction between the metallic solid atoms is low, pre-existing chemical bonds can be easily broken to form new ones. In other words, it is possible to alter the arrangement of the dislocation and create a new form by exerting force. On the other hand, strongly-bonded crystal structures of other solids, such as salt, are difficult to alter their shapes as they are easily broken by exterior force.

Effective Control of “Dislocation” is a Metallurgist’s Dream

Developing strong, unbreakable, and ductile materials is a long standing dream of metallurgists. The key question to consider here is how to control the movement of the dislocation within a metal.

Metallic materials are produced by mixing two or more atoms to form an alloy. Their properties depend on the ratio of atoms and the manufacturing process.

Giga Steel, successfully commercialized by POSCO, is a high-strength steel designed and developed to create twinning, structures in which the left and right sides are symmetrical each other like a mirror image or to alter the crystal structure during plastic deformation by controlling dislocation. It can be considered as state-of-art metallic materials.

Going Beyond the Norm

Metallic materials have many stories to tell and metallurgists are becoming more elaborate in telling these stories. Here, we will highlight two recent accomplishments in metallurgical research, the first being high-entropy alloys.

Traditionally, metallic materials were developed as alloys made by combining two or three minor elements with major one depending on the required properties. A high-entropy alloy is formed by combining five or more elements in identical or similar ratio without a major element. This method enables alloys to be produced in almost-infinite varieties, and alloys with excellent cryogenic properties, corrosion-resistant alloys, have already been studied and presented.

Study results reveal that high-quality mechanical properties of the high-entropy alloy are closely related to twinning. This reaches beyond the common knowledge of metallurgy as it was previously assumed that these alloys existed beyond the scope of twinning.

The International Cooperation Research Team of Graduate Institute of Ferrous Technology, POSTECH in Korea and KTH – Royal Institute of Technology in Sweden, developed a general theory of the atomisitic level and conducted quantum mechanics calculations. As a result, it was revealed that the high-entropy alloy is a different class of material in comparison to the conventional alloys and that twinning occurs more effectively, thus attaining high mechanical properties.

Ultra-Light and High Strength

The second accomplishment to highlight is the ultra-light and high-strength steel developed at Graduate Institute of Ferrous Technology, POSTECH. An alloy was designed to combine into steel containing high ratio contents of manganese and aluminum with a less amount of nickel, then the processing was controlled to produce small-sized secondary crystals.

Chemically stable secondary crystals were known to degrade the properties of metallic materials, and were thus avoided. On the contrary, the mechanical properties of the newly proposed alloy have been found to be superior to the conventional steel materials, including even titanium-alloys developed for aircraft materials. This implies that we should open a new chapter in the field of metallic materials with a new generation of high-alloy steel such as POSCO’s Giga Steel, high-entropy alloy, and ultra-light high-strength steel.

In Pursuit of a Safe and Sustainable Future

As descendants of “wise man (Homo sapiens)”, we should consider the future of our planet and civilization and demonstrate wisdom. The scientific knowledge that has led us thus far will guide us through the challenges faced by the humanity.

The role of metallurgists is also important. They would have to search deeply within the fundamentals, applications, and domains granted by Mother Nature to discover and apply versatile materials and contribute to creating a safe, efficient, and sustainable future.

In this spirit, The Steel Wire highlights the innovative use of metals in household appliances and electronic devices from air conditioners and cameras to laptops. Read on to see how innovative applications of metals have the power to present a new, more efficient way to live.

Breeze-Free Air Conditioner with Metal Cooling Panel

There may have been those even in the heat this past summer who didn’t want to use air conditioners due to direct blasts of cold air. Here’s good news: Samsung’s “breeze-free” air conditioner, Q9500, maintains a stable room temperature without blasting a single column of strong and direct wind.

How can air conditioners be “breeze-free”?

The company used a metal cooling panel and a micro hall-based air current passage system that constantly changes the direction of the air. Cold air is sent through 135,000 tiny holes and the short airways can reduce energy use by 65 percent. Also, climate control settings can be adjusted directly via smartphones using IoT technology based on weather data.

Samsung’s breeze-free air conditioner, Q9500, comes with metal cooling panels and 135,000 micro holes which maintain a stable room temperature without blasting strong and direct cold air. (Source: Flickr)

The even distribution of cool air allows air conditioners to naturally blend in as part of any space or room it occupies and eliminates the discomfort of direct, cold air.

Lightweight & Durable Cameras with Magnesium Construction

Global camera brands have long been searching for ideal materials to meet consumers’ needs for lightweight, mobile and durable cameras. For this reason, one of the prestigious features of top-end cameras in the market today is magnesium construction. This is due to magnesium’s lightness, strength and ability to shield users from electromagnetic waves. Magnesium is, in fact, the lightest structurally-used metal in the world with a greater strength-to-weight ratio than that of aluminum. This allows magnesium electronics bodies to be thinner and lighter.

For instance, the exterior shell of the Nikon D3 is made of a magnesium alloy. The product’s magnesium-alloy camera frame effectively protects the camera from invasive dust, moisture and electromagnetic interference with a self-diagnostic shutter mechanism tested to exceed 300,000 cycles.

The Nikon D3s’ magnesium-alloy camera frame effectively protects the camera from invasive dust, moisture and electromagnetic interference.(Source: Flickr)

Ultra-light Laptop with Duralumin

Over the years, new technologies have pushed PC makers to build ever lighter and thinner laptops with premium materials. Samsung also started to pursue metals that are lightweight yet durable. In the past, the company used magnesium-lithium sheets from overseas suppliers in order to keep their laptops lightweight. The sheets had good machinability but low hardness, making them vulnerable to dents. In order to overcome this, the company turned to POSCO’s specially designed magnesium sheets, duralumin*, known for its high-strength and lightweight qualities. In 2016, POSCO began supplying its magnesium sheets for the Notebook 9 that is just 840g. In 2017, the Samsung Notebook 9’s weight was brought down even further to 799g.

These magnesium sheets, made with a rapid solidification process that is capable of precision control, are tempered several times and undergo special heat treatment until they reach a final thickness of 0.5mm. POSCO succeeded in increasing the surface hardness by more than 20 percent and the yield strength by more than 50 percent, compared to its competitors, while still maintaining a high level of machinability.

Such advancements in lightweight and high-strength materials have allowed people the flexibility, mobility and convenience to work on the go and reduce inefficiencies.  

*Duralumin is a high-strength aluminum alloy made by mixing copper, magnesium and other elements.

POSCO supplies magnesium sheets for Samsung Electronics’ 2017 model of Samsung Notebook 9 that touts ultra-light, high-strength metal materials. (Source: Samsung Newsroom)

In today’s world, it’s hard to imagine life without electronic appliances and devices that provide a better quality of life. In a way, the invention and evolution of such products have redefined the way people live, work and play. The application of innovative materials has sped up and continues to allow manufacturers to add value to their products.     

The cryogenic high manganese steel is a high value-added material that POSCO proprietarily developed after more than a decade of research. It is the representative World Premium Product of POSCO. Cryogenic high manganese steel is a steel product that can withstand a very low temperature of -196℃, making it suitable for storing and transporting Liquefied Natural Gas (LNG). Also, because it is more weldable than conventional nickel alloy steel and 20-30% cheaper than nickel alloy steel, stainless steel and aluminum alloy steel, it is a solid alternative to these competing materials.

POSCO is constantly striving to develop and commercialize new steel products. Its recent registration with ASTM International strengthens its competitiveness in advanced steel technology. Teresa Cendrowska, VP of Global Cooperation at ASTM International stated, “POSCO is leading the standardization of new steel technologies at ASTM International and has become a model for other steelmakers by setting a new standard for high manganese steel.”

Last year, POSCO’s cryogenic high manganese steel was used for an LNG fuel tank for the world’s largest LNG-fueled bulk carrier (a bulk carrier using LNG as fuel) built by Hyundai Mipo Dockyard. In the future, POSCO plans to provide Solution Marketing to domestic and overseas oil majors and EPC customers. It also plans to sell World Premium Products in the energy sector and develop new markets.

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POSCO invested a total of KRW 255.4 billion and the 7CGL is expected to have an annual production capacity of 500,000 tons. By designing and constructing the plant with its own proprietary technology, POSCO was able to reduce construction costs, thereby securing cost competitiveness for its customers as well.

POSCO CEO Ohjoon Kwon and executives came together on April 26 to officially bring 7CGL online. From left to right: Seong Yu, head of the Technology and Investment Division; Shohei Yamazaki, purchasing organizing director of Renault-Nissan; Kiyoshi Kamishima, general manager of the Materials & Facilities Purchasing Division of Toyota; Jae-cheon Song, chairman of the Gwangyang City Council; In-hwa Jeong, a national assembly member; CEO Kwon; Nak-yeon Lee, governor of Jeollanam-do; Hyun-bok Jeong, mayor of Gwangyang; and Myeong-jin Seo, executive director of Hyundai & Kia.

CEO Kwon remarked, “POSCO opens up a new horizon in automotive steel with the completion of the 7CGL. This new line will allow POSCO to continue to provide differentiated products and customized solutions through smart technology.”

The 7CGL is attracting attention as one of the first plants to produce both hot-dip galvannealed (GA) and hot-dip galvanized steel (GI) at 1.5GPa  steel for automobiles. GA steel is preferred by Korean and Japanese automakers because it has excellent coatability and weldability as the coating layer is made of iron and zinc alloy, while GI steel is preferred by European automakers due to its excellent resistance to corrosion.

Previously, GA and GI steel sheets could only be produced at 1.2GPa due to surface and quality problems that occur before and after plating. POSCO resolved these problems by developing the “high hydrogen rapid cooling technology,” which forms high-intensity tissues in steel sheets before plating, and a “rapid cooling system,” which uses rapid cooling to smooth out the plated surface.

With the completion of 7CGL, POSCO now has seven operating CGLs  in Gwangyang, two CGLs in Mexico, and five CGLs in Thailand, India, and China. Through these CGLs, POSCO plans to produce 10 million tons of steel by 2018 and further solidify its status as a global automotive steel maker.

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POSCO supplies magnesium sheets for Samsung Electronics’ “2017 model of Samsung Notebook 9 Always.” The Notebook 9 series is Samsung Electronics’ flagship model that touts ultra-light, high-strength metal materials. (Photo courtesy of Samsung Newsroom)

Samsung Notebook has been working to develop laptops that are slim and lightweight without having to sacrifice durability. Typically, durable laptops and electronics had to come with heavy metals. In order to keep their laptops lightweight, Samsung previously used magnesium-lithium sheets from overseas suppliers, which had good machinability, but low hardness, making them vulnerable to dents.

Starting with duralumin (a high-strength aluminum alloy made by mixing copper, magnesium and other elements) in 2011, Samsung has been aggressively pursuing metals that are lightweight yet durable. In 2016, POSCO began supplying its magnesium sheets for the Notebook 9 that was just 840g. In 2017, Samsung’s Notebook 9 was brought down even further to 799g – helping to significantly expand Samsung’s presence in the ultra-light notebook market.

In World War II, magnesium sheets, known to be one of the lightest metals, were used in long-range bombers. More recently, they have been used in high-performance sports due to their high-strength and lightweight qualities. POSCO leveraged its own process technology to further enhance these properties and began to mass-produce and supply them in 2015. These magnesium sheets, made with a rapid solidification process that is capable of precision control, are tempered several times and undergo a special heat treatment until they reach a final thickness of 0.5mm. POSCO succeeded in improving the surface hardness by more than 20% and the yield strength by more than 50%, compared to its competitors, while still maintaining a high level of machinability.

In addition, Samsung Electronics applied the state-of-the-art plasma surface treatment method, the MAO (Micro Arc Oxidation) method, to the formed magnesium body. This improves its durability against external impacts, corrosion, and scratches – further enhancing its value as a premium product.

POSCO’s magnesium sheets were used in the bottom casing of the Samsung Notebook 9

POSCO is continuing to develop new products through close cooperation with Samsung Electronics – the two companies plan to leverage their respective strengths and technologies to launch various products according to customer needs. By developing their technology and customized materials, POSCO aims to reach their goal of providing more magnesium materials for mobile devices as well as making magnesium sheets the new standard for various mobile products.

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The bottom of the Gram 15-inch – made with POSCO’s ‘E-Form’ magnesium alloy sheet

In 2015, POSCO developed the ‘E-Form’ magnesium alloy, which significantly increases magnesium’s ability to be molded at room temperature (magnesium is known to have poor forming ability at low temperatures). The alloy was applied to the bottom of the Gram 14-inch and 15-inch.

Instead of stopping with the ‘E-Form’ alloy, POSCO continued to make further improvements and rolled out its ‘E-Form Plus’ alloy which demonstrated improved formability. LG Electronics incorporated the use of the alloy into the 13, 14, and 15-inch Gram in 2017, further solidifying their partnership.

The 2017 version of Gram features a battery life of up to 24 hours, a 40% larger cooling fan against heat, a backlit keyboard for enhanced ease of use and dual-channel memory slots for more convenient memory upgrading. In addition to these improvements, the 2017 Gram laptops recorded a lower or equivalent weight compared to the existing models [940g (13.3-inch model), 970g (14.0-inch model) and 1,090g (15.6-inch model)]. The Gram 15-inch won the 2016 iF Design Awards’ Gold Award and a Red Dot Design prize, and was also named the world’s lightest 15.6-inch laptop in the Guinness World Records.

The 2017 LG “All Day Gram” (courtesy of LG Electronics’ official blog)

The growth of the entire laptop market is slowing down due to the emergence of smartphones and tablets but ultra-light and slim laptops are enjoying growth at a rate of 15% to 20%, respectively, each year. According to market research firm, Juniper Research, when Intel announced its ultra-light laptop concept in 2011, shipments of ultra-light laptops throughout the world amounted to only 3.7 million units in 2011; but in 2016, they soared to 178 million units. And in 2017, ultra-light laptops are expected to account for 42.7% of the entire laptop market.

By steadily developing customized materials and processing solutions for its customers, POSCO is working to position magnesium alloy sheets as a valuable material for a variety of mobile products.

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His name may not sound so familiar. It is not as well-known as Genghis Khan, the ruler who laid the cornerstone of The Mongol Empire, but Saladin is still recognized as a beloved historical figure among Muslims. He is the one who fought for the Holy Land of Jerusalem on behalf of Islam during The Crusades, a fierce 200-year-war between European Christianity and the Islamic world in the 11-13^th centuries.

A noticeable part in the front of the statue of Saladin is the sword that he is holding with his right hand, pointing it up towards the sky. It may seem like an ordinary sword, but this blade, also known as the Damascus blade, contains an interesting history in relation to iron. Let us appreciate a part of the history of iron, through following the footsteps of this sacred weapon.

An invincible sword made of Wootz steel, captivates everyone’s heart

Firstly, one cannot help to wonder how the sword ended up with the name of Syria’s capital. It does not have obvious ties to Damascus, and its origins actually bring it back to ancient India.

Take a moment to look at the column in the photo above. It is made with steel, weighs six tons and measures 10 meters high. Judging from its pristine condition, which does not have a lot of rust, one may think it was made rather recently; however, it was erected 1700 years ago, during India’s Gupta Dynasty. Many scholars have conducted investigations on its composition to solve its mysteries, but they were not able to discover a definite reason as to how it has been able to remain rust-less.

This column, called “the iron pillar of Delhi”, is made with something called Wootz steel. Because of its durability, even to hammering, Wootz steel was mainly used for making sharp blades. It is unreasonable to think swords made with such an outstanding material to remain only in India; it was exported worldwide, to Russia, China and even to Persia. Eventually, swords made with Wootz steel captivated the hearts of the Damascus people in Syria.

But why is this specific sword called the “Damascus blade”, and not the “Indian sword” or the “Wootz steel sword?”

Damascus used to be the trade center of West Asia. Wootz steel blades were exported through the city and due to its high demands, it is predicted that a shortage in supply shortage must have occurred. At around 300 B.C., the spread of the Wootz steel blade began when merchants started to produce swords directly by hiring artisans. That is when the storied blade got its name as the “Damascus blade” – born and raised by India, but rising to fame only after it reached Damascus, Syria.

Strong and beautiful, the Damascus sword

Beginning with its manufacturing process, the Damascus blade was an extraordinary tool. While its blade is solid due to a mixture of carbon that allows it to maintain an even level of solidity, its body has a distinct pattern due to differences in carbon distribution that enables it to be shock absorbing. That is why a writer once described the sword as “a shining wave in a breezy pond.”

Because of its strength and beauty, the Damascus blade was a weapon coveted by many. One person who especially wanted one of the valuable swords was Mutawakkil, a caliph of Abbasid who ruled the Islamic world from the 8^th to 13^th centuries. He had heard of its reputation from southern India where it was being produced at the time, and eventually succeeded in obtaining this legendary weapon, after various attempts and paying a huge sum of money – only to lead him to his death.

He assigned his adjutant Bagyr as a keeper of the sword, and it just so happened Mutawakkil’s subordinate was planning a revolt against his leader. Bagyr later murdered Mutawakkil with the Damascus blade, his most precious treasure – ending his quest for the sword in an ironic fate.

A weapon that defeated the Crusades

It was not until the Crusades that the fame of the Damascus blade spread to Europe from Asia; it was Saladin’s army’s use of the Damascus blade that pierced crusaders’ thick armor and severed their swords in one swing.

However, there is another reason why this particular sword is incredible; it is not only strong and sharp, but also light and slim. One may think that the sword featured in Saladin’s statue is undersized. It’s almost hard to believe that a hero who once ruled over the world was wielded such a small sword, but not everything that is bigger is necessarily better. Saladin’s army was much more advanced in battle because of their mobility, than the crusaders who used heavy swords.

There are some urban legends of the lithe and powerful blade that exist from its heyday. When King Richard I, who lead the Crusades, showed off his sword, Saladin responded by throwing a piece of silk over his Damascus blade, which apparently finely sliced through the cloth.

There were also rumors such as that the devil taught humans how to make the Damascus blade, and while one can only wonder how reliable this tale to be, it surely reaffirms the blade’s reputation as tremendous weapon.

The Crusades eventually ended in defeat, and from an Islamic perspective, the Damascus blade is considered to be what successfully prevented the invasion of Christianity.

Since then, the Damascus blade has fought in battlefields around the world. But around 250 years ago, the manufacturing technique faded from the generations of artisans, and since then, it has not been restored. Even though we develop other weapons of mass destruction using steel at this day and age, the craft of making the historically significant blade has evaporated into a memory.

Will there be another day in the future when we will be able to appreciate the Damascus blade’s legendary pattern of “a shining wave in a breezy pond” once again?

Written by Changhoon Kang, author of ‘Era of Steel’

The opinions expressed in this POSCO Report piece are the author’s own and do not necessarily reflect the views of POSCO.

Traditionally, metal cutting methods have been used to manufacture machine components. The process would begin by shaping the metal through casting or welding, getting it to look as close as possible to the final product. To finalize the procedure, any unnecessary parts would be removed by a CNC (Computer Numerical Control) router. Using these types of cutting methods would accelerate the speed of production, but was considered wasteful since the majority of the starting material would be cut out and discarded. It is especially not appropriate for high-priced materials or materials that are difficult to cut.

Then there is additive manufacturing, which is a 3D printing technology that builds a final product through stacking layers of material, and then polished for a seamless appearance. The advantage of this method is that there is almost no waste of the material, which allows for the opportunity to create various prototypes without a separate mold or tool. A downside, however, is that it takes too long to manufacture, which makes it a tough choice for productivity.

Recently, General Electrics (GE), an American manufacturing corporation, officially joined the 3D printer business by assigning a merger of Arcam, a Swedish 3D printing specialized company, and the Germany-based SLM Solutions, to GE Aviation. Until now, 3D printing technology was primarily centered around plastic materials, but GE’s ambitious expansion into the 3D printing business indicates the rapid growth of new technology in producing major metal parts.

SLM solutions specializes in the Direct Metal Laser Sintering (DMLS) method – a printing technique that requires laser-firing a bed of powdered metal such as titanium, special steel, aluminum, cobalt chrome or nickel, melting together the powder to form a structure. Sweden’s Arcam has been manufacturing aircraft engine turbine blades by using the Electronic Beam Melting (EBM) method, which enables high-speed 3D printing by injecting 100 or so electron beams simultaneously into the metal. By combining the technologies of these two merging companies, a new high-speed 3D metal printer is surely to be developed in the near future.

Manufacturing Metal Parts with 3D Printing

Image credit: WH Williams

The multinational special steel company, Voestalpine Group, recently established a new research and development center for the 3D printing of metal components. At this center, 3D printing manufacturing technology for automotive and aviation sectors, medical devices and complex metal parts will be researched.

Creating metal parts with 3D printing requires powdered metal of excellent quality. Raw metals initially undergo vacuum melting to become an alloy, which then becomes atomized by spraying high-pressure inert gas through a nozzle, turning into powder. The powder must appear very round and uniform, so the core of this technology is to meticulously control the nozzle’s injection amount, temperature, pressure, gas quantity and speed — all depending on the type of the alloy. The atomized powder is then classified by size, ranging from 20μm to 100μm, after several filtering processes.

Designing the metal components to be suitable for 3D printing is also important. Since the printer builds the part layer-by-layer, surfaces must fulfill the requirements for a laser or electron beam to scan through. As a fine diameter of light from the laser passes through the designed lines and surfaces, the powdered metal melts topically and creates a new layer on top of the previously laminated surface. At this point, the part may have an overall directional angle, so the order of drawing lines and angle within each layer is also very crucial.

During the 3D printing process, if the metal powder particles fail to melt completely or if there is a delay in clotting, minuscule bubbles could appear. The ability to withstand fatigue and fractures is important, as these metal components are supposed to support the weight of an object. Minor bubbles or gas pockets could be critical flaws. To achieve a perfect density by preventing bubble formation, the beam’s speed must be balanced and adjusted to suit different types of alloys.

This process demands additional attention when using metals of alloy elements. Unlike pure metals, alloys can experience a large gap in temperature and be able to exist in both solid and liquid states if their composing elements carry a great difference in melting points. In these cases, bubbles are easily made. Although alloy properties are very important, a composition of alloys with distinct melting points is required and the difference of these melting points must be maintained at a minimum.

That is, the development of suitable alloy metals for 3D printing, including technology for assigning a product’s cross section and designing a laser beam’s pass-through, is the bottom line of component manufacturing technology. In addition, the thickness of a component is closely related to the diameter of metal particles. Therefore, it is recommended to design the final product to be as thick as the particles it is made of, and vice versa.

The Future and Mission of 3D Printing

The 3D printing process creates an extremely complex structure that cannot be produced through conventional precision casting or processing methods. In that sense, even components of the same purpose can be designed with completely different structures using 3D printing. Thus, it is possible to reinforce the component’s functionality by reducing the component’s weight or enhancing its cooling performance.

It is now possible to manufacture components to produce their final shapes with special alloy metals, which had been impossible with conventional processing methods. As of recently, only a few types of metals were available for 3D printing. However, the low prices and excellent quality of metals now available will enable new developments of special steel 3D printing materials that meet the purpose of each component, expanding the spectrum of 3D printing.

As powdered metals accumulate together almost instantaneously, alloy elements do not diffuse or segregate. It is possible to obtain a supersaturated solid solution of alloy metal that has refined grains, which will allow for uniformity in texture.

Traditional metal component manufacturers, including GE, are now pursuing the 3D printing process as a transitioning path to digital manufacturing. They believe that 3D printing, a combination of precise mapping software, high-speed 3D printing devices and printing materials, will bring new solutions to their business.

Furthermore, enterprises are now being given the task to discover a multi-component special steel alloy that fits the manufacturing businesses’ demand. Various alloy powders are also expected to further develop so that 3D printing can be recognized as an optimized method for manufacturing components made of special steel in the future.

Written by science technology columnist Dr. Junjeong Lee

The opinions expressed in this POSCO Report piece are the author’s own and do not necessarily reflect the views of POSCO.

Surgical stainless steel plays a vital role in the medical industry – it is used for a range of instruments, as well as orthopedic implants, such as bone screws and plates.

Precision Instruments

Scalpels are an invaluable tool, used to perform a broad range of surgical procedures. The use of scalpel-like instruments actually dates back to ancient Egypt, when special knives were used for embalming the bodies of members of the royal family. However, it was not until 1915 that Charles Russell Bard and Morgan Parker developed and patented the modern two-part scalpel, which consists of a blade and a handle.

Most commonly known as the B.P. handle scalpel, this features a blade forged from type 316L stainless steel, the type of steel that is most resistant to corrosion in the face of direct contact with biological fluid. Stainless steel is an alloy that contains 16 percent chromium, helping boost its famous corrosion resistance.

While performing any type of procedure, be it minor or extensive, surgeons need access to a wide range of instruments. In addition to scalpels, many other surgical tools are made from stainless steel.

These include Mayo scissors, both straight-blade and curved-blade variations, which are made from stainless steel, although more expensive titanium versions are also available. Straight and curved Mayo scissors are designed for cutting body tissue, as well as cutting sutures – essential steps for a host of different surgical procedures.

Another very common instrument used in hospitals and clinics around the world is the hypodermic needle. This is a hollow needle, used with a syringe to inject or extract fluids from the body. Many consider it to be one of the most important tools in modern medicine.

The hypodermic needle has gone largely unchanged for the past century, and because of its ability to remain sterile if treated properly, it has helped to significantly reduce the risk of contamination during medical care.

Stronger Orthopedic Implant Support

Metal alloys have been used for orthopedic implants since the beginning of the 20^th Century. Before this, medical professionals had experimented with the use of materials such as ivory, rubber, acrylic and even wood, but most ended up causing further health complications for patients.

Medscape mentions that metals made from iron, cobalt, chromium, titanium and tantalum are commonly used in modern procedures, as alloys made from these materials can be used safely and effectively. Medscape also states that these alloys’ mechanical, biological and physical properties play significant roles in the longevity of such implants.

The Journal for Orthopedic Science explains that stainless steel plates used for the internal fixation of fractures have been used for more than 100 years, when a medical company called Lane first introduced the metal plate. The journal notes that in 1912, another company, Sherman, introduced internal fracture fixation pieces that made improvements to the metallurgical formulation of the plate, increasing corrosion resistance.

Surgical stainless steel alloys (316L) are made from varying amounts of iron, chromium and nickel, and are currently used in the manufacturing of prostheses. Many orthopedic implants are still made of surgical stainless steel, and the material is used mainly for plates, screws and intramedullary devices.

New Medical Possibilities

In the world of advanced health technology, surgical robotics is becoming increasingly prevalent. Although skilled human technicians are still essential, surgical machines can perform less invasive tasks, and often enable a faster recovery time for patients.

Driving the success in many of these medical robots are stainless steel motors, which allow for aseptic conditions (freedom from contamination). Surgical robots also use metal alloy arms and hydraulics in order to perform the intricate operations – all requiring yet more steel.

Important Resource

Surgical stainless steel’s medical adaptability makes it a cornerstone material for doctors around the world. It is readily available, affordable and interchangeable – making it perfect for blades, needles, tools, implants and even robotics.

The use of surgical stainless steel often provides patients with faster recovery times – a factor that means that just about any medical environment you come across will bring you into contact with safe and sterile surgical stainless steel.

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Submarines therefore must be built using the best and strongest materials possible to be able to endure long, underwater missions, and deep sea exploration.

Any metal used to build a submarine must contain certain properties and attributes to adequately handle being submerged for long periods of time while incurring underwater pressure. The metal used to build a submarine must be dense, shape-forming, malleable, non-corrosive and lightweight.

Steel has the ability to withstand corrosion and avoid oxidizing reactions such as rust. It is also lightweight enough that it can be fast and effective in maneuvering underwater.

A Hull Lot of Steel

Submarines used for military activity have gone through many shape transformations since first being commissioned. Several designs were experimented with before settling on the recognizable hydrodynamic teardrop shape. The outer shell, or hull, of the submarine is commonly constructed of steel alloy.

Submarines can have either a double or single-hull construction, which affects speed or maneuverability depending on which type of hull is used. American submarines are typically made of a single-hulled steel plating layer that creates the optimized shape needed for advanced warfare capabilities.

Inside the outer hull is the pressure hull, which is responsible for allowing the submarines to reach depths of 250-350 meters. The pressure hull, one of the most important components of a submarine, is constructed of thick, high-strength steel that is divided into several compartments.

The pressure hull’s construction is a delicate process requiring high degrees of precision to build. If a hull contains any defects, it could jeopardize the integrity of the entire submarine.

With today’s modern nuclear submarines, the predominant material used in manufacturing is still mainly steel. In order to be able to carry delicate nuclear warheads, the submarine must be made strong and dependable. Steel is used to construct the inner hull that contains the vessel’s crew and inner mechanics, as well as the outer hull. The layer between the inner and outer hull is used as the submarine’s ballast tank system, which lets water in and out, enabling the submarine to rise and dive.

Setting Depth Records with Steel

On March 26, 2012, famed Hollywood director James Cameron and his DEEPSEA CHALLENGE expedition team set a world record with their submarine solo dive to the deepest known place on earth.

DEEPSEA CHALLENGE states that the historic expedition to the Mariana Trench’s lowest point, the Challenger Deep, which lies 6.83 miles (10.99 kilometers) below the ocean surface, was the first extensive scientific exploration in a manned submersible of the deepest spot on earth.

Several different types of materials were used to construct the DEEPSEA CHALLENGER submarine, however, the pilot’s sphere was built from steel.

According to DEEPSEA CHALLENGE, the steel orb was equipped to make sure the pilot gets oxygen, stays warm, and is shielded from the deep-sea pressure.

Engineers made the pilot’s chamber spherical because the shape can be both strong and light. They also made the steel 2.5 inches (6.4 centimeters) thick to withstand the crushing pressure of the deep.

The Ocean’s Steel Whales

As oceanic vessel technology advances, so too will the designs and materials used to build submarines. One aspect that will remain constant however, is the use of steel. Submarines will remain a vital part of national defense and further ocean exploration for many years to come. Designs will continue to improve submarines’ speed and maneuverability, as well as the depths they are capable of reaching.

Modern submarines, however, will continue to be made mostly of steel, proving that the metal is perfect for keeping the ocean’s steel whales swimming into the future.

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