Hot Rolled vs. Cold Rolled Steel: What’s the Difference

When you start a project, choosing between hot-rolled and cold-rolled steel can make a significant difference in your results. 

Hot-rolled steel is shaped at high temperatures, while cold-rolled steel is processed at room temperature for a smoother, stronger finish. 

Understanding the differences helps you select the appropriate metal for welding, building, or crafting items that require a professional appearance.

If you want to get the best results for your work, it’s important to know what sets these two types of steel apart. 

This article breaks down the pros, cons, and common uses of each, so you can make a wise choice.

How Hot-rolled Steel Is Made

Hot-rolled steel is made by heating steel to a temperature above 1100°F. At these high temperatures, the metal becomes soft and pliable, making it easy to shape. 

This allows you to roll the steel into large sheets, bars, or other shapes without cracking.

The rolling process begins soon after heating. You pass the steel through large rollers while it is still hot. 

This stretches and flattens the steel quickly. Because the material is hot and flexible, you can achieve a variety of shapes during this step.

After rolling, the steel is left to cool at room temperature. It does not go through any extra hardening or straightening process. 

Cooling in open air can cause the grain size to become larger, which makes hot-rolled steel more ductile and easier to work with. 

However, this process can also lead to minor casting defects and a less controlled shape.

Here are some common features of Hot-rolled steel:

• Surface Finish: A rougher texture, with a possible bluish scale from oxidation.
• Dimensional Tolerances: Less precise measurements and straightness compared to cold-rolled steel.
• Strength and Ductility: Good strength with higher ductility and plasticity.
• Typical Uses: Structural components, railway tracks, beams, and general construction.

Hot-rolled steel is typically chosen for applications where precise size and a smooth finish are not crucial. 

The process makes the material strong and durable, but also more affordable for large-scale projects.

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How Cold-Rolled Steel Is Made

Cold-rolled steel starts with Hot-rolled steel. Hot-rolled steel is first formed at high temperatures and then allowed to cool to room temperature. This cooled steel is used as the base material for making cold-rolled steel.

In the cold rolling process, the steel is rolled again, but this time at room temperature. It gets passed through rollers that squeeze it thinner. This step increases the strength and hardness of the steel.

After rolling, the steel may undergo additional steps, such as annealing or temper rolling. These steps help reduce residual stress and improve the microstructure of the steel.

Key features of cold-rolled steel:

• High precision: Tighter thickness and dimensional accuracy
• Smooth surface finish: Cleaner, more attractive surface
• Increased strength and hardness: Better mechanical properties than Hot-rolled steel
• Consistent microstructure: Improved material quality

Cold-rolled steel is often used where precise size, a smooth finish, or high strength are required. You can find it in cars, appliances, and sometimes in agriculture equipment. 

The variety in surface finishes and close control over thickness make this steel popular for products where appearance and accuracy are crucial.

Key Differences: Hot-rolled vs Cold-rolled Steel

Hot-rolled and cold-rolled steel differ in their manufacturing processes, appearance, and dimensional stability. These differences affect their strength, surface finish, and the best uses for each type.

Differences In Manufacturing Processes

Hot-rolled steel is made by rolling steel at high temperatures, above the steel’s recrystallization point. This makes the steel easier to shape and form.

Cold-rolled steel is processed at room temperature after it has been hot-rolled. This extra step makes the steel harder and gives it a smoother finish.

Here are the main differences in how they are made:

• Hot-rolled: Rolled at 1,700°F or higher
• cold-rolled: Rolled at room temperature after initial hot rolling
• Hot-rolled: Allowed to cool slowly after forming
• cold-rolled: Passed through rollers to reach exact thickness and smoothness

Because cold-rolled steel is worked at lower temperatures, it gets stronger but is more expensive to produce. Hot-rolled steel requires less processing, making it generally more cost-effective.

Comparison Of Mechanical Properties

The way each steel type is manufactured affects its strength, hardness, and stiffness.

cold-rolled steel is usually stronger than Hot-rolled steel. The process of rolling at lower temperatures increases its hardness, yield point, and tensile strength. This is due to a process called work hardening.

Hot-rolled steel is not as strong, but it is tough and easy to work with. It’s often used where strength is less important than ductility or toughness.

Property Table:

Differences In Surface Finish And Appearance

Surface finish is another area where these steels are different. Hot-rolled steel has a rough and scaled surface. The reason is it’s cooled in open air, so scale forms on its surface.

cold-rolled steel has a much smoother and shinier surface. The extra rolling step at low temperature removes imperfections. This makes it better for products where looks matter.

Key differences:

• Hot-rolled Steel: Blue-gray, rough, with mill scale
• cold-rolled Steel: Shiny, smooth, no scale
• cold-rolled steel often needs little finishing before painting or coating
• Hot-rolled steel may need grinding or sandblasting before final use

Dimensional Accuracy And Precision

If you require precise shapes and exact measurements, cold-rolled steel is the better choice. It is rolled closer to final size, so it comes out straighter and more accurate.

Hot-rolled steel is more prone to warping as it cools, due to its inherent shape change. The final size may be slightly off. It’s suitable for projects where exact dimensions are not critical.

Comparison:

• cold-rolled Steel: Tighter tolerances, consistent shape, sharper edges
• Hot-rolled Steel: Looser tolerances, rounded or uneven edges
• cold-rolled is used for parts like shafts and bars where measurements must match closely
• Hot-rolled is often used for frames, beams, or parts that are welded or cut later

📌 Also Read: What Temperature Does Aluminum Melt

When to Use Hot-Rolled Steel (Best Applications)

Hot-rolled steel is an excellent choice for projects where strength is essential but a smooth surface is not needed. 

You can often find it in structural components because the rough, scaled surface is not a problem.

Common examples include:

• I-beams and columns
• Railroad tracks
• Square and rectangle tubing
• Sheet and plate for construction

This type of steel is well-suited for projects where appearance is not a primary concern. 

If you are building a frame or core structure that will be hidden or painted, Hot-rolled is usually the easiest and most affordable option.

Hot-rolled steel is also used for:

• Welding and fabrication shops
• Heavy machinery parts
• Large equipment bases
• Agricultural equipment

If you need to keep costs low, Hot-rolled steel is often less expensive than cold-rolled steel. It is made with less processing, so you save money, especially for large projects.

When strength, size, and cost matter more than surface look, Hot-rolled steel is often your best pick.

When to Use Cold-Rolled Steel (Best Applications)

Cold-rolled steel is an excellent choice when you require strong, precise, or smooth parts. It is commonly used in industries like automotive and appliance manufacturing.

You should use cold-rolled steel when:

• You need parts that require tight tolerances or exact measurements.
• Surface finish is crucial for your project, particularly for items that will be visible or touched.
• The steel needs to be harder and stronger than Hot-rolled steel.

Some of the best uses for cold-rolled steel include:

cold-rolled steel is also ideal when you need thin sheets or strips. These thinner materials can handle forming and bending better without cracking.

Since cold-rolled steel is stronger and stiffer, it is well-suited for parts that are subject to stress or require maintaining their shape. 

If your project values both appearance and performance, cold-rolled steel is often the better option.

Cost Comparison: Hot-rolled vs cold-rolled Steel

When deciding between Hot-rolled and cold-rolled steel, price is often a big factor. Hot-rolled steel usually costs less than cold-rolled steel. 

This is because it requires less processing and does not require extra steps, such as reheating.

Average Price Table

Why Hot-rolled Steel Costs Less

• Hot-rolled steel is produced more efficiently with fewer steps.
• It does not get reheated, which saves time and energy.
• The process uses less equipment.

Cold-rolled steel is more expensive because it requires additional processing. This includes cooling and reheating. It is also rolled at room temperature, which takes more time and care.

Availability

• Hot-rolled steel is often available in large sheets or in larger sizes.
• Cold-rolled steel is commonly used for smaller, more precise products.

Long-Term Value

• You may pay more for cold-rolled steel upfront, but it can save you money in the long run if you require tight shapes or a smooth finish.
• For projects where appearance and exact dimensions are crucial, cold-rolled steel may be a better choice, even though it initially costs more.

If cost is your primary concern, Hot-rolled steel is usually the more cost-effective option. But for detailed projects, cold-rolled steel may be worth the higher price.

How to Choose Between Hot-rolled vs cold-rolled Steel

Selecting between Hot-rolled and cold-rolled steel depends on the specific needs of your project, your budget, and understanding which properties are most important. Surface finish, strength, cost, and dimensional accuracy will play a key role in your decision.

Project Requirements Checklist

Before selecting a type of steel, consider the project's basic requirements. 

Think about the following questions:

• Do you need tight tolerances or precise shapes?
• Is a smooth finish or appearance important?
• Will the steel be subjected to high-stress loads or used for structural support?
• Are you welding or machining the steel?

Hot-rolled steel is suitable if you require large quantities, irregular shapes, or do not concern yourself with surface finish. 

Its rounded edges and scale make it less ideal for jobs where appearance and detailed specifications matter.

Cold-rolled steel is ideal for parts that require precise measurements, clean lines, and a smooth, polished finish. 

This makes it suitable for visible surfaces, machine parts, and applications where precise sizes are required. Ensure that you match your steel choice to both the job and the required look.

Budget vs Performance Trade-offs

Cost can be a significant factor in decision-making. Hot-rolled steel is usually less expensive, especially for large quantities or simple shapes. It also costs less to produce because it needs less processing.

If you require stronger material and a more attractive appearance, cold-rolled steel is more expensive but offers these benefits. 

Cold-rolled options are stronger and more consistent in terms of size and thickness. You will often pay more for this quality, but it can save you time in the long run if you require fewer adjustments later.

Use this chart for a quick comparison:

Choose based on how much value each feature will add to the finished product.

Common Mistakes to Avoid

Many people pick steel based only on price, which can lead to problems down the line. Others overlook tolerance needs or surface appearance until it is too late. Here are some things to watch out for:

• Not checking size and finish specs before ordering
• Picking cold-rolled steel only for its look, even when you do not need the extra cost or strength
• Ignoring how the steel will be cut, welded, or bent during the project

You should also avoid assuming that one type of steel is suitable for all tasks. For example, using Hot-rolled steel where tight tolerances are needed often means extra work later. 

Read your project plans carefully and ask for detailed specs if you are unsure.

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Which is Better for Welding: Hot Rolled Steel or Cold Rolled Steel

When deciding between Hot-rolled steel and cold-rolled steel for welding, there are a few key points to consider. Each type works a bit differently when welded.

Hot-rolled steel is usually easier to weld. The process used to make it leaves the steel less complicated and more ductile, which helps prevent cracks and distortion during welding.

Common reasons to use Hot-rolled steel for welding:

• It is less likely to warp or distort while welding.
• The softer surface is easier for your welding electrode to penetrate.
• You can weld larger pieces without as much risk of creating stress in the metal.

Cold-rolled steel can also be welded, but you need to be more careful. It is stronger and harder than Hot-rolled steel, which can lead to a few challenges.

Things to keep in mind with cold-rolled steel:

• It is more likely to distort or crack if you use too much heat.
• Its smooth, oily surface may need extra cleaning before welding.
• Tighter tolerances can make it harder for welds to fuse if the fit isn’t perfect.

If you need to weld something that requires very precise dimensions, cold-rolled steel may be necessary, but it requires more care. 

For most welding projects, Hot-rolled steel has fewer issues and is friendlier for both beginners and experienced welders.

Conclusion

Now that you understand the differences, you can choose the right material for your project, whether it's hot rolled steel's cost-effectiveness for structural work or cold rolled steel's precision for finished products. 

Remember, each type requires proper handling and welding techniques for optimal results.

For successful steel fabrication, quality equipment makes all the difference. ARC Captain offers essential welding safety gear, high-performance synergic MIG welders, and versatile stick welders to handle both steel types with ease. 

Whether you're shaping rough beams or crafting precise components, we've got the tools you need. Check out our collection and weld with confidence.

Frequently Asked Questions

Hot-rolled and cold-rolled steel exhibit significant differences in terms of strength, cost, flexibility, and suitability for various applications. Knowing these facts can help you choose the right material for each project.

Which is stronger: hot-rolled or cold-rolled steel?

Cold-rolled steel is stronger than Hot-rolled steel. It undergoes additional processing at lower temperatures, which enhances its strength and hardness. Hot-rolled steel is less strong but is usually cheaper and easier to produce.

Is Hot-rolled steel better than cold-rolled?

Hot-rolled steel is not always better than cold-rolled steel. It is less expensive and works well for projects where high strength and exact measurements are not needed. For jobs that require tighter tolerances and greater strength, cold-rolled steel is often the preferred choice.

What are the disadvantages of Hot-rolled steel?

Hot-rolled steel can have a rough surface and slight size changes as it cools. These factors can make it harder to use in precise or finished projects. It is also not as strong as cold-rolled steel.

Which is easier to bend hot or cold-rolled steel?

Hot-rolled steel is easier to bend. The metal is less hard and more flexible, which makes it better for jobs that require a lot of shaping or bending.

Can cold-rolled steel be used outdoors?

You can use cold-rolled steel outdoors, but it is more susceptible to rust because it lacks a protective coating. If you use it outside, you may need to paint or coat it to protect it from weather.