Cold Rolled Steel Plate

As a products that hot-rolls steel plate 2mm or thinner at room temperature, cold rolled steel plate is also called 'the flagship of steel products,' since it is the most difficult to manufacture of all steel products and requires high technology. Thin and with beautiful surface, cold rolled steel plate is used as outer plate and interior material of automobiles, home electronics, construction materials, etc. that are closely related to our lives, Anita Steel & metals possesses an annual cold rolled steel plate production capacity of ten thousand tons and is lately striving to develop high-value-added cold rolled steel plates such as ultra-high strength steel plate in step with the worldwide trend for lightweight vehicles




Pickled & Oiled Steel Plate

The surface of steel plate is treated with oil to prevent oxidation after iron oxide and impurities attached to the surface of hot rolled steel plate are removed with hydrochloric acid, etc. It is mostly used for automobiles, construction materials, and pipe materials.

- Major Products SPHE, SPHD, SPHC, SAPH310, SAPH370, SAPH400, SAPH440, SPFH540, SPFH590, JIS-SPHC, JIS-SPHD, JIS-SPHE, ASTM A1011, EN DD11, DD12

Hot Rolled Galvanized Steel Plate

With zinc plated on the surface of hot rolled steel plate, the product boasts outstanding corrosion resistance. Resistant to corrosion, it is used as construction and industrial materials as for fences, containers, guard rails, and agricultural pipes.
- Major Products SGHC, SGH340, SGH370, SGH400, SGH440, SGH490, JIS-SGHC, JIS-SGH340, JIS-SGH400, JIS-SGH440, JIS-SGH490

Electro-Galvanized Steel Plate

As electro-galvanized cold rolled or hot rolled steel plate, the product demonstrates outstanding corrosion resistance and processability. It is mostly used as material for home electronics such as LCD, TV, DVD player, copy machine, and refrigerator.
- Major Products SECC, SECD, SECE, SECEN, SEFC340, SEFC390, SECUD, JIS-SECC, JIS-SECD, JIS-SECEN, EN DC01+ZE, EN DC03+ZE, EN DC04+ZE

Galvanized Steel Plate

Galvanized steel has outstanding corrosion resistance as a galvanized cold rolled steel plate and is mostly used for home electronics, construction materials, and internal parts of automobiles. Galva-annealed steel has outstanding weldability and processability as a steel plate that has annealed the zinc plate of cold rolled steel plate and is mostly used for inner/outer plates of automobiles.
- Major Products SGCC, SGCD, SGCD1, SGCD2, SGCD3, SGC340, SGC370, SGC400, SGC440, SGC570, JIS-SGCC, JIS-SGCD, ASTM A653, EN DX51D+Z, EN DX52D+Z, EN DX54D+Z, SGACC, SGACD, SGACEN, SGACUD, SGARC340, SGARC440, SGAFC590

Color Coated Steel Plate

With cold rolled steel plate, galvanized steel, aluminum, stainless steel, etc. coated with various colors, the product boats beautiful color and surface and is mostly used for home electronics, construction materials, assembling metals, etc.
- Major Products CGCC, EN DX51D+Z, EN S220GD+Z, EN S280GD+Z, EN S350G

304 Stainless Steel vs 316 Stainless Steel

Different grades offer unique resistance to corrosion

Contrary to its name, stainless steel is valued for its anti-corrosion properties rather than its resistance to staining. It's an alloy composed primarily of iron—but when combined with other elements, it can achieve properties desirable for a range of applications. Chromium is the defining ingredient that makes stainless steel what it is, making up a minimum of 10.5 percent of total composition. Other common alloy ingredients include nickel, titanium, aluminum, copper, nitrogen, phosphorous and selenium.

The difference between 304 and 316 stainless steel is the presence of molybdenum, which provides a much higher degree of corrosion resistance—especially for more saline environments where exposure to chlorides is expected. For outdoor site furnishings, stainless steel is an ideal corrosion-resistant material that will withstand long-term exposure to the environment.

Natural corrosion resistance

Different quantities of chromium, as well as other materials, can be used to achieve varying degrees of corrosion resistance. The two most common stainless steel grades are 304 and 316.

Corrosion is a natural phenomenon. Pure elements, such as iron, inherently react with surrounding environments. In fact, very few elements can be found naturally in their pure form—gold, silver, copper and platinum being some of the few examples.

Chromium oxide creates a reflective finish that protects internal structures

Rust is the process where iron molecules combine with oxygen in the presence of water. The result is a red flaky oxide that deteriorates easily—exposing more material to further corrosion. Iron and standard carbon steels are highly susceptible to this type of corrosion.

Stainless steel has the innate ability to form a protective surface that prevents corrosion. How does this happen? The chromium found in all stainless steels reacts quickly with oxygen environments, much the same as iron. The difference, however, is that only a very fine layer of chromium will oxidize (often only a few molecules in thickness). This incredibly thin barrier is highly durable and non-reactive. It adheres to stainless steel surfaces and won't transfer or react further with other materials. It is also self-renewing in that it will replenish if damaged or removed. Once oxidized, or passivized, stainless steel typically rusts at a very low rate of less than 0.002 inches per year.

When kept in its best condition, stainless steel offers clean and bright surfaces ideal for many building and landscape designs.

304 Stainless Steel

Stainless steel provides an attractive, clean finish with low maintenance cost

304 stainless steel has a high resistance to rust. It withstands corrosion from most oxidizing acids and is often used for kitchen and food applications. However, it is susceptible to corrosion from chloride solutions (notably saline environments with high amounts of sodium chloride). Chloride ions can create localized areas of corrosion, called "pitting," which can spread beneath protective chromium barriers to compromise internal structures. Solutions with as little as 25 ppm of sodium chloride can begin to have a corrosive effect.

304 grade is the most common form of stainless steel used around the world. It contains between 16 and 24 percent chromium and up to 35 percent nickel—as well as small amounts of carbon and manganese. The most common form of 304 stainless steel is 18-8, or 18/8, stainless steel, which contains 18 percent chromium and 8 percent nickel.

316 Stainless Steel

316 grade is the second-most common form of stainless steel. It has almost the same physical and mechanical properties as 304 stainless steel and contains a similar material make-up. The difference is that 316 stainless steel incorporates about 2 to 3 percent molybdenum, which increases corrosion resistance—particularly against chlorides and other industrial solvents. Alternative 300-series grades can contain up to 7 percent molybdenum.

316 stainless steel is commonly used in many industrial applications involving processing chemicals, as well as high-saline environments such as coastal regions and outdoor areas where de-icing salts are common. Due to its non-reactive qualities, 316 stainless steel is also used in the manufacture of medical surgical instruments.

Versatile applications

Chromium oxide creates a reflective finish that protects internal structures

Both 304 and 316 stainless steels (as well as other 300-series grades) use nickel to maintain an austenitic composition at lower temperatures. Austenitic steels ensure a versatile balance of strength, workability and corrosion resistance, making them ideal for outdoor architectural and landscape applications. The benefits of stainless steel include a long service life that will retain an attractive, clean finish with low maintenance cost. It also maintains a high value if and when equipment and parts need to be decommissioned.

Hot Rolled vs Cold Rolled Steel

Learn the benefits and drawbacks of each

There are so many types of steel out there, making up various shapes, grades, specifications, finishes and other processing considerations. One key distinction among prefabricated steel products is the difference between hot rolled versus cold rolled steel.

Why the difference?

It may seem obvious, but some types of steel are better suited for certain applications. Knowing which to use can help avoid spending more than you have to on raw materials. It can also save you time and money on additional processing. In other words, this guide will help you avoid complications and achieve better results—at the best price possible.

It's important to note that the difference between hot rolled and cold rolled steel is one of process. As you can imagine, "hot rolling" refers to processing done with heat. "Cold rolling" refers to processes done at or near room temperature. Although these techniques affect overall performance and application, they should not be confused with formal specifications and grades of steel, which have to do with metallurgical composition and performance ratings. Steels of different grades and specifications can be either hot rolled or cold rolled—including both basic carbon steels and other alloy steels.

With that, let's get into some specifics.

Hot rolled steel

Hot rolled steel is steel that has been roll-pressed at very high temperatures—over 1,700˚F, which is above the re-crystallization temperature for most steels. This makes the steel easier to form and also results in products that are easier to work with.

Hot rolled steel is steel that has been roll-pressed at very high temperatures

To process hot rolled steel, manufacturers first start with a large, rectangular billet. The billet is heated and then sent for pre-processing, where it is flattened into a large roll. From there, it is kept at a high temperature and run through a series of rollers to achieve its finished dimensions. Picture glowing, white-hot strands of steel running through compression rollers at high speed. For sheet metal, rolled steel is spun into coils and left to cool. For other forms, such as bars or plates, materials are sectioned and packaged.

Steel shrinks slightly as it cools. Since hot rolled steel is cooled after processing, there is less control over its final shape, making it less suitable for precision applications. Hot rolled steel is often used in applications where minutely specific dimensions aren't crucial. Railroad tracks and construction projects often use hot rolled steel.

Hot rolled steel can often be identified by the following characteristics:

• A scaled surface—a remnant of cooling from extreme temperatures
• Slightly rounded edges and corners for bar and plate products (due to shrinkage and less precise finishing)
• Slight distortions, where cooling may result in slightly trapezoidal forms—as opposed to perfectly squared angles

Hot rolled steel is ideal where dimensional tolerances aren't as important as overall material strength, and where surface finish isn't a key concern. Where surface finish is a concern, scaling can be removed by grinding, sand blasting or acid-bath pickling. Once scaling has been removed, various brush or mirror finishes can also be applied. Descaled steel also offers a better surface for painting and other surface coatings.What are the benefits of hot rolled steel? It typically requires much less processing than cold rolled steel, which makes it a lot cheaper. Because hot rolled steel is allowed to cool at room temperature, it's essentially normalized—meaning it's free from internal stresses that can arise from quenching or work-hardening processes.

Cold rolled steel

Cold rolled steel is essentially hot rolled steel that has been processed further. Once hot rolled steel has cooled, it is then rolled to achieve more exact dimensions and better surface qualities.

Cold rolled steel is essentially hot rolled steel that has been processed further

Cold "rolled" steel is often used to describe a range of finishing processes—though, technically, "cold rolled" applies only to sheets that undergo compression between rollers. Things like bars or tubes are "drawn," not rolled. Other cold finishing processes include turning, grinding and polishing—each of which is used to modify existing hot rolled stock into more refined products.

Cold rolled steel can often be identified by the following characteristics:

• Better, more finished surfaces with closer tolerances
• Smooth surfaces that are often oily to the touch
• Bars are true and square, and often have well-defined edges and corners
• Tubes have better concentric uniformity and straightness

With better surface characteristics than hot rolled steel, it's no surprise that cold rolled steel is often used for more technically precise applications or where aesthetics are important. But, due to the additional processing for cold finished products, they come at a higher price.

In terms of their physical characteristics, cold worked steels are typically harder and stronger than standard hot rolled steels. This is because cold finishing essentially creates a work-hardened product. It's worth noting that these additional treatments can also create internal stresses within the material. In other words, when fabricating cold-worked steel—whether cutting, grinding or welding it—this can release tensions and lead to unpredictable warping.

Manufacturing and product design

Depending on what you're looking to build, different types of materials each have their own benefits and drawbacks. For unique projects or one-off productions, prefabricated steel materials can provide the building blocks for any structural configuration imaginable.

For projects where you'll be manufacturing many units, casting is another option that can save time in machining and assembly. Cast parts can be made to almost any form in a range of quality materials.

Whatever your project, know that Reliance Foundry houses many metal fabricating operations. To learn more about our offerings, contact our Sales Department.