The words “cold-drawn,” “cold-rolled,” and “hot-rolled” are commonly used in steel production. Knowing how these different steel varieties are manufactured and their practical uses are critical to ensuring you have the ideal materials for any project. Choosing the perfect steel type would save your time and cost while also ensuring that you are providing your customers with the highest quality products.
Hot Rolled Steel
The term “rolling” means the process by which steel is manufactured. Steel that has been subjected to a high level of heat treatment is referred to as hot rolled steel as the manufacturing takes place at extremely high temperatures. Manufacturers start with huge, rectangular metals, also called billets. Manufacturers next heat the rectangular metals before transferring them to further processing, which involves flattening them into big rolls.
The molten steel is pressed at extreme temperatures of around 926℃ (1700 °F) during the hot-rolling procedure. Steel optimally recrystallizes from 750 to 1,300 °F, allowing for better reshaping and forming. The steel is left to cool once rolled in the mill in the required shape.
Characteristics of Hot Rolled Steel
The characteristics listed below can assist you in identifying hot rolled steel:
● Cooling from extreme temperatures leaves residues on the surface of the stainless steel bar stock, giving it a scaly appearance.
● Cooling causes slight distortions, such as slightly trapezoidal geometries with imperfect angles.
● Shrinkages and a lack of precision while finishing of round ground metals give slightly rounded edges and corners.
Advantages of Hot Rolled Steel
Hot rolled steel has the following advantages:
● Hot rolled steel is less expensive to process as compared to cold rolled steel since the processing time is shorter.
● Hot rolled steel cools at ambient temperature. It implies it has no or minor internal stresses due to quenching or work-hardening.
● The hot rolling process is carried out at higher temperatures, so the steel round rods produced can be easily shaped and formed. Hot rolled steel makes the most basic shapes, such as UC, UB, SHS, RHS, flats, etc.
● It’s perfect for applications in which tolerance isn’t a big problem.
Disadvantages of Hot Rolled Steel
Hot rolled steel has the following disadvantages:
● Dimensional flaws caused by heating-induced expansion and cooling-induced warpage/shrinkage.
● It possesses a rough surface that must be bugged or removed before the finishing procedure can begin.
● There are some minor distortions.
Applications of Hot Rolled Steel
As hot rolled steel cools, it shrinks slightly. Due to it, manufacturers can’t control the final form or shape. As a result, hot rolled steel is typically used in applications that do not demand strict tolerances, such as the following:
● Automobile parts – for example, frames and wheel rims.
● Truck frames
● Railroad tracks
● Agricultural equipment.
● Construction
Cold Rolled Steel
In general, cold-rolled steel is hot rolled steel, which has been processed further. Rolling encompasses many steel-forming processes, including polishing, grinding, and turning. The phrase “cold rolled” is used to describe stainless steel bar stock that has been compressed.
While hot rolled steel is made by heating it to an extreme temperature and then cooling it, cold-rolled steel requires an additional step. The steel is cooled and re-rolled at ambient temperature in cold reduction mills, either by press braking or cold roll forming. This procedure helps in the formation of the required shape and size of steel round rods, stainless steel bar stock, or brass round stock.
Characteristics of Cold Rolled Steel
The following characteristics can differentiate cold rolled steel:
● Smooth surfaces give an oily touch to them.
● The surface possesses a greater level of finish and better tolerances.
● The corners of cold-rolled stainless steel bar stock are well defined.
● Concentric uniformity and straightness are typically better in tubes.
Advantages of Cold Rolled Steel
The following are a few of the advantages of employing cold rolled steel:
● Cold-rolled steel round rods and brass round stock frequently have smooth, glossy surfaces free of corrosion and rust. As a result, they’re helpful when appearances are essential.
● They are often more rigid and stronger than hot-rolled steel. This property enables cold-rolled steel to be suitable for usage in high-stress applications.
● Cold rolled steel will not shrink during the forming process, so it can be used to make more precise components with regular and perfect shapes.
Disadvantages of Cold Rolled Steel
Cold rolled steel has the following disadvantages:
● It is expensive as it requires additional processing.
● Internal stresses in the round ground metals may occur due to further treatments, resulting in unpredictably warping in certain situations.
● There are fewer shapes available, such as sheets and hollow section shapes.
Applications of Cold Rolled Steel
Cold rolled steel is best used in applications that require a superior round ground metals surface finish and higher tolerances. The following are a few applications of cold-rolled steels:
● Mechanical components
● Aerospace parts
● Home appliances
● Metal furniture structures
● Water heaters
● Fan blades
● Rods, strips, sheets, and bars
Cold Rolled Steel VS Cold Drawn Steel
Cold drawn steel is manufactured at ambient temperature, just as cold-rolled steel. Cold drawn steel forms thin shapes, such as steel round rods, brass round stock, or wires, whereas cold rolling provides a flat shape to any material. It is done by hammering hot rolled steel into a die, which is the machine that rotates and pushes the round ground metals in its finished elongated shape. The cross-sectional area of this finished shape could be rectangular, square, round, or hexagonal, based on a die. Cold drawn steel is excellent for maximum durability products such as structural parts and shafting, plus consumer goods with high aesthetic quality.
Cold drawn steel has many of the same advantages as cold-rolled steel. Cold drawn steel has a strong tensile strength plus a polished, smooth finish due to the high pressure. Cold drawn steel, like cold-rolled steel, does not alter shape throughout manufacturing, resulting in a consistent shape and thickness. To obtain the desired size, cold-drawn steel is frequently drawn using different dies, resulting in greater production costs.
Hot Rolled Steel VS Cold Rolled Steel
Hot rolled steel is also flat as cold-rolled steel. Hot rolled steel would change size and shape throughout the cooling procedure since it passes through manufacturing rollers at an extreme temperature, leaving it less suitable for applications demanding uniform thickness. The hot-rolled steel round rods and brass round stock are less robust than cold-rolled steels and have a coarser finish.
There are certain advantages of employing hot-rolled steel rather than cold-rolled steel. The hot rolled steel is much more pliable than cold rolled steel, making it simpler to work on. Hot rolled steel is less expensive since the rolling process involves fewer steps. For example, round ground metals do not have to get cooled before processing into the rollers, plus the thickness can also be reduced by just one pass, while cold rolling needs multiple passes.
O’Hare Precision Metals-Manufacturers of High-Quality Steel Parts
At O’Hare Precision Metals, we can create customized metal parts for various industries, including automotive, household appliances, aerospace, and many more, regardless of the steel you choose. We use the best quality hot rolled steel, cold drawn steel, or cold-rolled steel, based on the steel you need. Our professionals are well-versed in steel parts production, so you can rest assured that you’ll get the best possible outcomes.