STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

Have you ever seen a blast furnace? The picture below — molten iron pouring out from the blast furnace — might be familiar to you, and it could be the first thing on your mind when it comes to blast furnaces. However, seeing the blast furnace in real life isn’t a daily event.

The POSCO worker in the photo is clearing the area around the tap hole (an exit where the molten iron is discharged) so that the molten iron can smoothly flow out of the blast furnace. That is not easy since the discharged molten iron reaches over 1,500 ℃. However, POSCO employees can do this job owing to the pride and passion they possess for the blast furnace.

Iron ores become molten iron on entering the blast furnace. Then the molten iron is taken to the converter to filter all impurities. Next, the molten iron is shaped into large cuboids, which are then sent to different plants to be various steel products. This entire mechanism is called an integrated steelmaking process. The name says it all. It’s a process that flows continuously from the molten iron stage to the final steel product stage. So the entire blast furnace and steelworks are under operation 24/7 all through the year!

So, what if the blast furnace is idled? The blast furnace itself will be hardened into a huge mass of solid iron, so to restore the process and operate normally, it should be dismantled and replaced with a new one. The cost reaches 500 billion to 1 trillion KRW, and the reconstructing takes several months. Another problem is that it doesn’t end with just the blast furnace. As mentioned earlier, the steelworks is a continuous process, so if the blast furnace stops operation, all the plants that use the molten iron from the blast furnace need to cease their operation as well, meaning that the whole steelworks would have to be shut down.

That is why for the workers at POSCO, the blast furnace is like the subject of “sacred worship.” Did you know that torch lit with the sun was used to ignite the blast furnace No. 1 of Pohang Works in 1973? The records of POSCO history describes the moment very movingly, saying that “each torch relayers in turns took over the ‘flame of the sky.’”

▲ A sacred ceremony of the Olympic torch lighting in honor of Prometheus, who gave fire to humans. Inside the circle shows Tae-Joon Park lighting the torch with the sun to ignite POSCO’s first blast furnace (June 7, 1973).

As a result of this ceremony, the blast furnace has become a sublime object that must be protected for the POSCO workers. The commitment is as deep and heavy as the ancient Persian religion, Zoroastrianism, which cherished the fire used for rituals, and the people of the Stone Age desperate to preserve the flame which was obtained with much difficulty. The reason for this is because steel created with the ‘flame of the sky,’ laid the foundation for the development of the Korean manufacturing industry, and is everywhere in the advancement of the Korean economy.

There are some steelworks around the world where blast furnaces have been idled. As a result, other plants attached to it stopped operation as well, which led to the whole steelworks having to be shut down. As the steelworks were closed, the local economy collapsed as well, deteriorating the entire economy of a country eventually.

So idling the blast furnace is a big problem we need to pay attention because there is no simple solution when we look at the effects caused by it. If it’s shut down, the whole steelworks is closed subsequently. POSCO operates four blast furnaces at Pohang Works and five blast furnaces at Gwangyang Works, respectively. It is necessary to understand that if the furnaces stop operation, local economies might collapse as well. The consequence is enormous.

Although we’re not aware, our heart pumps and circulates blood throughout our body to keep us alive. POSCO blast furnaces are just like our ‘heart.’ They pour out molten iron 24/7 and help the economy of Korea ‘thrive.’

▲ A POSCO worker dealing with molten iron

POSCO’s furnaces are under operation based on cutting-edge technologies such as Big Data and AI. Due to this outstanding feature, POSCO was designated as a ‘Lighthouse Factory’ by the World Economic Forum (WEF) for the first time in Korea. When it comes to blast furnaces, the spirit of POSCO workers is still alive even in the high-tech world of today.

The answer to today’s question became a little serious, but we can’t help it. Because POSCO Newsroom — being a part of POSCO — also shares the pride and passion of the workers at the steelworks. POSCO Newsroom will be back with more interesting stories! See you next time!

* This article was written with help from Jun-Seok Park of POSCO Pohang Works Technology Development Section.

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

Anyone who doesn’t like getting deliveries? ʕ •ɷ•ʔฅ Probably none. In Korea, almost everyone — men and women of all ages — shops online and receives home deliveries. You can order anything and everything online these days — from clothing and electronics to even food! Then, is this possible for steel as well? That’s the question that flew into Newsroom today.

POSCO steel products are ordered and sent to companies that make the end products that people use — consumer products like mobile phones, cars, and refrigerators! When we receive parcel deliveries, it usually comes in a small box. Can you imagine how big steel could be shipped? POSCO Newsroom shows you how it’s done.

l Purchase POSCO Steel ‘Online’

▲ POSCO client companies buy steel through ‘e-Sales’ of [Steel-N.com]

Client companies can place orders directly through this site. When the order comes through, POSCO marketers look at the order form and checks if POSCO can produce the steel as requested, and also whether it can be delivered by the desired date. Then, they decide whether to produce the steel in Pohang or Gwangyang Works. Next, the system automatically checks the order with the marketers rechecking for any possible errors. After this process, the order is confirmed and then production begins!

While non-members can freely purchase products in general online shopping, an inquiry with client information is needed in advance to purchase POSCO steel. If a direct inquiry is hard, you can consider buying POSCO steel through a general trading company.

l How Is Such Large and Heavy Steel Delivered?

Have you ever seen a delivery truck in front of your house? You must have seen all the parcels stacked up inside. The items we order online are usually delivered by trucks. What about large steel? Well, POSCO’s steel could be sent on trucks, vessels, and even trains!

Once the steel is produced and its quality checked, it’s tightly packed according to its feature and the client’s request. The packing protects the steel from rain, abrasion, and other damages. The steel then leaves the warehouse in one of these three ways: land transport, sea transport, and rail transport, depending on the order.

Let’s suppose you ordered a box of fruit, and it was placed at the bottom of the parcel stack and delivered to you. Wouldn’t your fruit be scratched and bruised? This is why POSCO makes sure the steel is transported safely and appropriately so that customers can use them at the best quality. Now let’s look into the details of each transportation method.

Land Transport
Land transport is a way of loading steel onto cargo trucks and transporting them on roads. Best suited for short-distance transportation, this method is usually used in delivering to nearby areas. It’s easier to arrange than other modes of transportation, making it perfect for urgent deliveries. POSCO also makes a lot of steel that is too large to be transported by regular trucks, so there are special vehicles for this purpose. These vehicles enable the safe delivery of large-sized products.

Sea Transport
Sea transport is considered the most economical method since large amounts of steel — 3,000 to 5,000 tons depending on the size of the ship — can be transported at a single time. POSCO Pohang Works is located on the East Sea, and Gwangyang Works on the left side of the South Sea. So the location of both steelworks makes it appropriate for sea transport since the steel can be shipped to the docks as soon as production is complete. When shipping domestically, POSCO uses a specialized ship called, RO-RO (Roll-On, Roll-Off). Rather than having to ship products one by one, the steels are loaded on a truck in advance, and the truck itself is placed on the RO-RO ship. It makes the work process much more efficient. POSCO is exporting steel to numerous countries around the world as well.

Rail Transport
When transporting steel by rail, a ‘Special Freight Car’ is utilized. Products sensitive to moisture are transported using a freight car equipped with screens and waterproof curtains to protect products. Rail transport causes lower CO₂ emissions than land and sea transport. It’s also appropriate for pre-scheduled transportation and safer — since there’s a lesser risk of accidents.

As seen here, POSCO’s clients can use the online ordering system to order the steel they desire, as well as check the production and delivery process, just as they can with online shopping. Overseas deliveries and other special deliveries are no problem as well. That is all for today! If you have any questions about POSCO in the future, please send them to POSCO Newsroom!

* This article was written with help from Vin-Na Choi of POSCO Sales and Production Coordination Office

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

POSCO volunteered spreading silicate fertilizer at a farm in Gwangyang last year. Since POSCO is a steel maker, the connection with fertilizer might seem odd. However, steel and fertilizer are quite close — closer than we think. Let’s see how these two go together.

l What Is Silicate And What Is Slag?

To make iron, iron ore is first smelted in a large blast furnace. After this, the iron ore is separated into molten iron and stony by-product. This by-product is called a ‘blast furnace slag.’ A blast furnace slag has a specific gravity different from molten iron, so it is easily separable.

When slag is first separated, it looks like hot molten lava. So to cool it down, high-pressure water is sprayed on it. After it cools down, the slag takes a sand-like form, and this is called ‘granulated slag.’ The granulated slag is then dehydrated and pulverized into pellet-like shapes about the size of 2 to 5mm. This slag is rich in silicic acid (SiO₂), which is essential for rice farming, so it is made and utilized as a ‘silicate slag fertilizer.’

The main component of silicate fertilizer is silicon (Si). Silicon is not an essential component for plant growth itself, but it is a vital component for the rice plant since 5-10% of its weight is silicic acid — the rice plant is even nicknamed a ‘Silicate Plant.’ Silicon is the most abundant in soil, but because it doesn’t separate well, the rice plant can not absorb the silicic acid. That’s why you need silicate fertilizer. Silicate fertilizers provide the rice plant with silicic acid that is absorbable — enhancing its ability to withstand heavy rainfall, strong winds, and pests.

In Korea, rice that is sticky with a weak scent is generally considered ‘good’ rice. Silicate fertilizer lowers the protein content in the rice, improving the taste and enhancing the quality and standard of the rice.

Slag, which is a by-product of ironmaking at steelworks, contains 25-30% of soluble silicic acid. POSCO has contributed to increase farm income by continuously supplying slag to fertilizer companies since 1974, the year after the Pohang Works began operation. Did you know that all silicate fertilizer used in Korea is made from POSCO slag? In the past 45 years, a total of 13.76 million tons of silicate fertilizers have been supplied to domestic rice paddies.

l Make The Earth Greener

It is a known fact that greenhouse gas causes global warming. In terms of carbon dioxide emissions from the agricultural and dairy industries in Korea, the numbers add up to 21 million tons per year — with 29% accounting from rice paddies. The use of silicate fertilizer is set to help reduce the amount of greenhouse gas emitted.

Since rice is grown with water-filled into the paddies, the organic matters in the paddy soil break down into methane (CH₄). Research from agricultural experts states that the iron ions (Fe3 +) in the slag fertilizer reduce the methane concentration from the paddy fields by 15-20%. The fertilizer is also expected to contribute to the ultimate reduction in greenhouse gas emissions by 1.1 to 1.5 million tons per year in Korea!

Increasing the use of silicate slag fertilizer is helpful to all — farmers, fertilizer companies, and the whole environment. First of all, the fertilizer improves the soil quality, which in turn enhances rice quality and grades. This eventually leads to higher incomes for the farming communities. For the government, the use of fertilizer reduces methane gas from the paddies, decreasing the amount of overall greenhouse gas. Also, better rice taste boosts the consumption of rice, which increases the competitiveness of fertilizer companies. So silicate slag fertilizer is not only environmentally conscious but also beneficial to the whole society.

POSCO plans to expand the demand for silicate slag fertilizer and develop overseas export markets so that the by-products are recycled well all around! (๑❛ᴗ❛๑)

[See more about the use of by-products here!] POSCO’s Eco Driver: Steel 2

* This article was written with help from Keon-Mok Sohn of POSCO By-Product Recycling Group

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

Magnets attract iron, and because of this, they are utilized in various forms. There are a lot of magnets that we can see in our daily lives as well — like the tiny magnets on souvenir magnets that stick on the fridge door, magnetic snaps that help items close tightly, and so on.

But if iron is in our body, why aren’t we attracted to magnets? Let see the reason in detail.

 l Iron — Essential for Our Bodies Too!

We can not live without oxygen, and it is the red blood cells that deliver this oxygen to cells all over the body. A molecule called hemoglobin in the red blood cells contains iron. Oxygen sticks to the iron here and moves around the body. So we can say iron is essential in our lives not just because of the benefits it provides, but because it carries oxygen around our body, thus making us stay alive.

Now that we know we have iron in our body, the next question might pop up — “Will magnets attract blood because of the iron in it?” Many scientists also had this question and have got the answer. Because if magnets do attract blood, we must be careful of the magnets around us!

Fortunately, the iron in our blood isn’t attracted to magnets. Iron is almost everywhere in our body but in tiny quantities. The amount of iron in an adult’s body put together is 3.5g. The iron contained in blood only is just 2g. This small amount is spread all over the body, so obviously, it isn’t greatly affected by the pull of magnets.

But this explanation isn’t perfect. Because in the case of super magnets, it could attract any magnetic substance no matter how small the amount is. So let’s find out a more accurate reason for this!

l What Keeps Our Body Safe From Magnets?

Hemoglobin molecules that contain iron tend to repel from the magnet when attached to oxygen. In contrast, oxygen-depleted hemoglobin molecules are attracted slightly by magnets.

A Youtube creator arranged an experiment regarding this explanation as well. Take a look at the real experiment! (Korean)

Hemoglobin in our blood is mostly attached to oxygen. Also, blood is composed mostly of ‘water,’ which tends to repel from magnets. So even if you put a strong magnet close to your body, you can see your body moving away rather than sticking to it. Isn’t it amazing?

You’ve probably seen an MRI (Magnetic Resonance Imaging) equipment in hospitals or medical dramas. An MRI is a device that lets you see inside the body using powerful magnetic fields. If blood is attracted to the magnet, the person inside the MRI would be in grave danger. However this never happens because the iron-containing blood doesn’t respond very much even to a powerful magnet. Also, blood circulates the body moving swiftly in the blood vessels, so the effect of the magnet is reduced even more! So don’t worry!

Was the answer satisfying? Just like the various steel products made by steelmakers, such as POSCO, make our daily lives more convenient and happier, it is important to remember that iron in our bodies plays an important role too! That’s all for today! See you next time! Bye~!

* This article was written with help from science communicator Jung-Wan Mok, and Youtube creator <Gwa Bboon Ssa>

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

Your dad was right to call Earth, ‘a planet of iron.’ Our planet was born about 4.6 billion years ago. It’s said that small planets — made up of rocks or metal masses — collided and merged to form the Earth. In the beginning, Earth was nothing more than a ball of hot magma, and as it gradually cooled down, iron and nickel that are relatively heavier sank to the bottom of the Earth, while lighter rocks rose to the surface and formed the crust.

Now, this is just a plausible hypothesis since no one saw this entire process. However, these two things are for sure — Iron has been on Earth ever since the beginning, and it has also played a significant role in human civilization. So, let’s look into the details!

l The Role of Iron In Our Civilization

Mankind advanced into the Iron Age from the Stone Age and the Bronze Age. Iron was stronger than bronze and readily available in nature, making it suitable as materials for tools. The iron beads of Egypt — made around 4,000 B.C. — was the first item humans made with iron, and the Iron Age arrived at around 1,000 B.C. Do you know what age we are living in today? Surprisingly, we are still living in the Iron Age. So this Iron Age has lasted more than 3000 years!

Before the Iron Age, humans dug into the ground to make houses, or crushed and cut out stones to build dolmens or pyramids. But as civilization evolved into the Iron Age, humans started making buildings using iron since iron was strong enough to make living space much safer and more stable. Before iron came along, most materials used in buildings were stones, bricks, and wood. So there was a high risk of tall buildings to collapse — since these materials were quite heavy, the weight was tremendous. But as iron emerged as the main material of architecture, constructing tall buildings became possible. The sturdy steel columns could support the weight of those buildings.

▲ The tallest skyscraper in Korea, Lotte World Tower! POSCO’s steel were used here!

Have you been to the Lotte World Tower(555m) in Seoul? It is the tallest building in Korea and the fifth tallest in the world. To build skyscrapers you need super strong and tough iron. That’s why POSCO’s own latest high-performance heat-processed ‘High Strength Steel’ was used in the construction of the Lotte World Tower. Thanks to the strong, durable steel, it was possible to create such a wonderful, tall architecture. As you can see here, iron and steel make the city safe and attractive with its role in the construction. We can also encounter steel in so many areas of our daily lives — like the buses and cars we ride, and the frying pans and cutlery of the kitchen.

l Iron — In Charge Of Life On Earth !

Can you guess the element with the largest mass on our planet? It’s ‘Iron(Fe).’ It accounts for 35% of Earth’s weight. But if you take a look around, it’s hard to understand this statement — there just isn’t that much iron around. Then, where is all that amount of iron? Well, it’s all hidden under the ground. As mentioned earlier, iron is a heavy material, so all of them sank to the Earth’s core.

The iron in the core has a significant role. It creates Earth’s magnetic field. Telling the North and South poles on a compass to find directions is possible because of this. A magnetic field is generated by conductive and magnetic materials, such as iron or nickel. The iron — in a liquid state at the core of the earth — creates the magnetic field as the earth rotates.

We can use a compass and also see the beautiful aurora at the poles, all thanks to Earth’s magnetic field. Not only that, but it also protects the Earth from the strong energy — the solar wind — of the sun. Without iron and its magnetic field, the Earth would have been a life-less planet, like Venus. So we are all alive here on Earth, thanks to iron!

Now you know why Earth can be called ‘a planet of iron!’ POSCO Newsroom will be back with a new and exciting story soon! Bye-bye ~! (*•̀ᴗ•́*)و ̑̑

* This article was written with help from researcher Eung-soo Choi of POSCO Technical Research Laboratories

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

Steel is used in the construction of large and heavy structures, giving POSCO this kind of impression. Other than the child who sent this question, perhaps a lot of people think this way too since POSCO Newsroom has been getting many questions regarding large steel used in buildings and cars.

Let’s see where steel is used. From high bars at playgrounds to skyscrapers, running cars and trains, steel bridges, and ships, most of them are considered heavy and square, giving them a chilly look. So it is a common belief that steel goes by this impression too. But actually, this doesn’t go to all of them. Steel can be large and heavy, but at the same time small and light!

l Overcoming Gravity And Into Space!

Did you know that steel can be used to make a spacecraft? You might think that this is obvious because spacecraft are large and heavy too! But if steel was just a heavy material, could it be used in building spaceships that have to go up high in the sky?

The material for a spaceship’s body must be as light as possible because the heavier the aircraft becomes, the more fuel it will consume, and the slower it would fly — due to gravity. However, light materials like plastic can’t be used as well since they aren’t durable. So special alloy materials such as duralumin are mainly used in making spaceships.

▲ If you want to see the stainless steel spacecraft from rocket maker SpaceX, click here!

January 2019, Elon Musk, the CEO of Tesla, announced that he would build ‘Starship’ out of stainless steel. Elon Musk is the founder of SpaceX, a rocket & spacecraft manufacturer. SpaceX is working on the development of a starship that can transport people from Earth to space — specifically to Mars.

Originally, the starship was to be made of carbon fiber, which is both light and durable. However, the material was changed to stainless steel since it was cheaper — one-hundredth the cost of carbon fiber — and could better withstand high temperatures with a melting point of 1,538 ℃. The starship will be 50 meters long and nine meters in diameter. Steel isn’t just for structures on the ground, but suitable for space adventures as well. Isn’t it amazing?

l In Your Pockets Today

You might have read about it in the papers, but there is steel in our smartphones as well. The silver rim of the Apple iPhone X is POSCO’s stainless steel.

▲ The shiny silver rim of iPhone X! It’s made of POSCO’s stainless steel!

The POSCO product used here is ‘non-magnetic, ultra-clean stainless steel.’ It has quite a long name, but you can easily get the idea of the product from it. The steel used for phones should be non-magnetic since it shouldn’t interfere with the phone connection. Additionally, the surface of the product must be ultra-clean — without scratches, bubbles, or deformations. That’s why ‘non-magnetic, ultra-clean stainless steel’ is the perfect material for smartphones!

Steel that fits a smartphone — the size of a palm and weighing only 174g — is the same stainless steel used for spaceships. But much thinner and lighter. The sleek and ‘edgy’ design that the steel rim provides is an additional feature. It shows a glimpse of what steel can do!

The answer to the question of whether POSCO makes only large and heavy steel is ‘Half correct and half wrong.’ Like mentioned above, steel could be used on a giant spaceship, and also on a hand-sized cell phone. Whether it’s steel used for aircraft or steel used for mobile phones, they all start with the same molten iron, but the applied technology is diverse — From needle to aerospace. Don’t you think this is the real strength of steel and POSCO? ⌯’▾’⌯

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

Another interesting question today! This child wants to know what is the thinnest and thickest steel in the world. Let’s take a closer look at the thinnest and thickest steel POSCO can make and their uses.

Put simply, POSCO can make steel that is thinner than toilet paper, and also steel thicker than a Big Mac hamburger. Now, let’s look into the details.

Well, a three-layered toilet paper that you see in the restrooms is about 0.35mm thick. This could probably be the thinnest item you might see around you. And as you know, since this toilet paper is so thin, it tears easily. Surprisingly, there’s steel as thin as tissue, yet strong and stretchable.

This steel is 0.2mm thick — thinner than toilet paper — but it doesn’t break like plastic or glass, and is called Cold Rolled Steel. This Cold Rolled Steel is made by rolling cold steel into a flat and thin form and then reheating it. In the end, it becomes a premium material with a shiny surface. The steel that we easily see in car interior parts or the kitchen is this Cold Rolled Steel.

Now, let’s learn about the thickest steel! At POSCO, thick plates of steel are called Steel Plates. These Steel Plates are also easily seen around us, used in the construction of large ships, various buildings, and bridges over rivers and seas. Then how thick is the thickest POSCO Steel Plate?

The answer is 200mm. It’s about the same size as one hand span of an adult. These thick plates are used mainly in factories that produce energy — like oil, natural gas, and electricity — necessary in our daily lives. Some of these factories include offshore oil & gas platforms in distant seas and power plants that produce electricity on land.

▲ An offshore structure in the middle of the ocean (Image source: Maersk Drilling)

Since offshore structures are located in the middle of the ocean, it has to stand firm against the fierce waves. It would be a huge problem if something so big collapses. That’s why thick Steel Plates are used at the base of the structure.

What about the power plants that generate electricity? If you look at the picture below, you can see tower-like structures that resemble a chimney. The thick Steel Plates are used here, and they enable the structure to withstand high temperature and high-pressure steam.

▲ Steel Plates are necessary in power plants to withstand high temperature and high-pressure steam! (Image source: SIEMENS)

Let’s go into the details. A power plant burns coal to boil water in the boiler. When the water boils, it creates water vapor(steam). This water vapor(steam) is then applied to run a generator and produce electricity used in our everyday lives. So to generate electricity safely, thick Steel Plates are necessary.

Today, we’ve seen the thinnest and thickest steel. These steel are everywhere, from our sparkling kitchens to offshore structures in the middle of the ocean! Do you have any other questions? Please feel free to ask POSCO Newsroom. ʕ•ﻌ•ʔ

* This article was written with help from researcher Seung-Ho Yu of POSCO Technical Research Laboratories

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

Today’s question is about the English saying, “Strike while the iron is hot.” The child who sent this question wants to know why we should strike iron. Let’s explore the science behind this saying with POSCO Newsroom.

First of all, let’s take a look at the process of how a blacksmith works to explain the reason why we should strike the iron while it’s hot. Have you seen blacksmiths on TV before? A blacksmith is a craftsman who makes tools and equipment by heating and hammering metals such as iron, copper, and tin. Sickles used for farming, as well as horse hooves and knives, were all born thanks to blacksmiths.

| Why Do Blacksmiths Heat the Iron?

Blacksmiths put solid hard iron into a forge and heat it at a temperature high enough to soften it. After the heated iron turns red, It is then pulled out with tongs and hammered to form a shape. The most important thing here is the timing.

If you miss the timing and the iron cools down, shaping it becomes hard — no matter how hard you strike it. This hints the meaning hidden behind the saying, “Strike while the iron is hot.” To shape iron, you should work on it soon after it’s molten. Because if you don’t, the iron will turn solid hard as before, and changing its shape then would be impossible. Putting that into consideration, the message of the saying would be this. “There is a timing for everything, so you shouldn’t put off things that need to be done now, for later.”

| Even In POSCO Steelworks Today, “Strike It While It’s Hot!”

The method of blacksmiths in the past is also applied to the steelworks of today. Molten iron from the furnace is first molded into a cube-shaped half-finished product (slab) and left to cool down. This slab goes into a reheating furnace when making a product. It’s just like how blacksmiths worked with their forge. Next, the reheated slab passes through the rolling mill and is winded into thin rolls, resulting in the end-product — a hot-rolled coil. The manufacturing process below will help you understand better.

The blacksmiths’ way of working in the past is re-enacted in the steelworks of today, through state-of-the-art technology and fully automatic facility. POSCO’s steelworks have evolved even further with AI technology. Through AI, knowing exactly when the iron should be heated or cooled off, and when it should be hammered or compressed, became possible. This enables the manufacture of high-quality and high-performance products that meet the needs of clients.

There are various sayings of different cultures that refer to iron and steel — like the Korean saying, “Iron gets stronger, the more it is struck on”, the American saying, “The Finest steel has to go through the hottest fire”, and the Chinese saying, “Out of the hottest fire comes the strongest steel”. As can be seen here, most of the sayings that are related to iron imply that harsh, extreme conditions and hardships enable growth. Perhaps this is why steelmaker POSCO has such a fierce and strong image.

Now you know the story behind the use of ‘iron’ and ‘steel’ in sayings. Isn’t it quite interesting? POSCO Newsroom hopes everyone who is going through a difficult time would not lose hope but go on, overcome, and become stronger — just like the sayings we saw today! Please feel free to ask POSCO Newsroom if you have any other questions!

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

*Admiral Yi Sun-sin: A navy admiral who led the Joseon Dynasty navy and is still a beloved historical figure by Koreans.
*The Joseon Dynasty: A Korean dynastic kingdom that lasted from 1392 to 1897.

Several invaders of Joseon recorded that the Joseon navy fired arrows, which were as huge as girders. The girder mentioned here is the ‘missile’ of Joseon. Isn’t it amazing that there was a missile even back then? Let’s look into this missile in detail.

The missile of Joseon has the name, Dae-jangun-jeon. ‘Dae-jangun’ in Korean means, ‘the Great Admiral’, and ‘jeon’ means, ‘arrow’, so its name alone shows how frightful this weapon was to the enemy. Admiral Yi Sun-sin — commander of Joseon Navy — reported to the king that he had smashed boats with this weapon after winning the Battle of Dangpo (1592) — the Joseon navy had sunk 21 ships then. Dae-jangun-jeon was the largest and most powerful weapon in Joseon.

▲ A scene from the film, depicting the Great Battle of Myeongnyang (Source: Naver Movie)

When we say cannonballs, we automatically think of round-shaped iron balls because of its name, but “Dae-jangun-jeon” is quite different. It isn’t round but instead stick-shaped, giving it the name — Joseon Dynasty’s missile. According to records of the time, the weight of one Dae-jangun-jeon was around 33.7kg, and its range was 1.14km. Then how could this heavy object fly a long-distance?

The ‘Cheonja Chongtong Gun’ was used to fire the Dae-jangun-jeon. And to get this huge missile to fly, iron was needed. One might think that huge amounts of gunpowder can make missile fly farther. However, gunpowder is just a trigger. Additionally, a missile made with just ‘strong’ iron would crack inside the cannon due to the explosive power of gunpowder. Let’s see the details in the image below.

The main body of Dae-jangun-jeon is made of wood, but it has iron on the head to attack the enemy, on the tail to withstand gunpowder, and also iron wings so that it can fly farther. So for the Dae-jangun-jeon to be strong enough to defeat the enemy and withstand the explosive power in the cannon, it needed iron. According to the records, the iron used to make weapons in the Joseon Dynasty was iron that contained fewer impurities (low-carbon steel).

Just as coke is put into the furnace to melt iron ore at the steel mill these days, iron was made with charcoal during the Joseon Dynasty too. There is a lot of carbon in charcoal, resulting in massive amounts of carbon — impurities — in the molten iron as well. Iron, which contains many impurities, is strong but quite fragile, so it is not suitable for cannonballs. It is also difficult to change its shape into the desired missile shape. By reducing the impurities in the molten iron, iron can be easily straightened and stretched than before.

The secret behind the Dae-jangun-jeon was iron that is hard and strong, yet easily shapable!

Thanks to an interesting question today, we could learn about both history and steel. Don’t forget that Admiral Yi Sun-sin was able to save the country thanks to “iron” and the skills of ancestors to create “iron”!

* This article was written with help from researcher Seung-Hyeon Jo of POSCO Technical Research Laboratories, and curator Kyung-Ju Chae of the POSCO museum.

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

Here we have another cute question at POSCO Newsroom. It’s asking who’s stronger, Iron Man or Superman (aka Man of Steel). Well, this is a tough question to answer. The child who wrote this must have sent it here because both characters have ‘Iron’ and ‘Steel’ in their names. So first, let’s take a look at the two characters in the movies.

▲ Source: Naver Movies

Remember the line “I am Iron Man.”? This line marks the beginning and the end of the Marvel Universe. Tony Stark made the Iron Man suit and became Iron Man himself to survive from a serious chest injury. The Iron Man suit was pure science itself. It had built-in weapons that enabled combat and was strong enough to endure a crash with a fighter plane, go underwater, and even fly into space.

▲ Source: Naver Movies

Then what about Superman — the original super hero? Superman was born on the planet ‘Krypton’. He’s also called ‘Man of Steel’ because he is strong and powerful just like steel. Even when he was still young, he drew up a school bus that had crashed into the river to save his friend. Now you know why he has ‘Steel’ in his name, right?

Perhaps the two characters got their names because both are as tough and strong as ‘Iron’ and ‘Steel’. But who would win if they fought? Well… Don’t you think it’s unlikely for two superheroes to fight each other? If they meet, they’ll probably work together to defeat the villain. Just like the Avengers!

[A quick question!] Isn’t iron and steel the same thing?

At POSCO newsroom, we’re going to talk about the ‘Iron’ and ‘Steel’ in the names of the two heroes. Some might think iron and steel are the same. But actually, they are two very different words. POSCO Newsroom visited a researcher at POSCO Technical Research Laboratories to find out more. Shall we listen to the explanation?

The atomic number of iron is 26, and its element symbol is Fe. Strictly speaking, pure iron would be an accurate expression for iron since it describes a state of pureness — without any impurities or other metals. But it is hard to find this pure iron directly around us because most of it exists in a form mixed with various impurities. Iron ore is a typical example. When carbon (element symbol C) is added to this iron (Fe), steel is born.

As seen above, steel is born when iron meets carbon. The type of steel produced varies, depending on the amount of carbon and the added elements. However, most of the material — made of iron — that we see in our daily lives is steel.

Where is this iron used? Iron — in the pure state — is too soft and weak to be used in everyday life, but instead widely used for experimental or electrical use. Then, is Iron Man made of iron? The answer would be ‘No.’ If the Iron Man suit was an iron 100% suit, Iron Man would probably have ended with the first movie — being unable to survive for the next one. So it would be safe to say that the Iron Man suit might be made of steel or some other material.

The materials for an Iron Man suit should not only be strong but also fit for other purposes as well. Have you seen the jet engine on the palms and feet of Iron Man? To be able to fly with those jet engines the hands, and feet of Iron Man must be of heat resistant steel. POSCO produces ‘heat-resisting steel’ by adding a variety of alloying elements to steel. So this would be appropriate for the Iron Man suit. Another POSCO product GIGA STEEL could be applied too since it’s light yet durable.

There are also some opinions that the Iron Man suit is made of nickel and titanium alloy. Titanium is a much stronger material than steel and POSCO produces and sells titanium products as well. Well, let’s leave the suit story here for now!

Iron Man and Superman are both superheroes saving the planet and protecting us, so let’s hope that they’ll never have to fight each other, ever. We saw today that the ‘Iron’ in Ironman and ‘Steel’ in Man of Steel are not the same. Don’t forget that! And also remember the iron material we see around us is not pure iron, it’s actually steel!

* This article was written with help from researcher Jong-Hoon Kang of POSCO Technical Research Laboratories.