When placing an order with a mill, service center, or stockist, it’s helpful to know the difference between hot rolled and cold rolled steel. Which you choose (hot or cold) depends on the purpose of your component and how it’s manufactured.
Sullivan Steel distributes both hot and cold rolled steels in multiple grades and in any quantity required. We aim to meet client specifications; our expertise ensures that customers get a steel that fits their process.
Difference Between Hot Rolled and Cold Rolled Steel
As the “hot rolled” name suggests, this steel is processed while the metal is still hot—immediately following production. In contrast, cold rolled steel is a hot rolled steel that’s been cooled and annealed. It then undergoes additional treatment.
Hot Rolled Steel
Hot rolled steel is formed using a rolling mill, forging-type operations, or a piercing mill, at temperatures typically greater than 1,700˚F / 927˚C (above the recrystallization temperature of many metals). Hot worked product has a rough surface and experiences some size distortion due to cooling.
Cold Rolled Steel
Cold rolled steel uses hot rolled product as its starting stock. The metal is cooled to room temperature, then annealed and further finished. Cold drawn steel has a smooth, shiny surface and can meet tighter tolerances for size and mechanical properties than hot worked material.
Working with Hot and Cold Rolled Steel
Customers must typically remove scale and defects from a hot rolled metal’s surface by grinding and/or polishing. And after machining the shape of the hot rolled steel component, it may still require additional heat treatment.
The advantage of cold rolling is that a customer can get a steel very close in size to their final part, which means minimal machining. Cold rolled steel can also be worked to reach the final component's specific properties (such as hardness, tensile strength, yield strength, percent elongation, and surface finish). If using cold rolled steel, further heat treatment may not be needed.
Economics and Price of Hot and Cold Rolled Steel
Hot rolled steel generally comes at a lower cost than cold rolled simply because hot rolling can follow the mill’s steel production process with no delays.
However, considering the entire manufacturing process of a component, hot rolled material needs more machining to remove surface defects than cold rolled. This work adds to the total manufacturing cost of a part, as does additional heat treatment (which may not be necessary if using a cold rolled steel).
When looking at the total economics of manufacturing, it’s wise to consider the price of hot rolled vs cold rolled steel, as well as the machining and treatments required to create the final component.
Applications for Hot and Cold Rolled Steel
Hot rolled steel is typically suited to applications where tight starting tube or bar size tolerances aren’t required, such as:
- Structural components
- Railway equipment
- Automotive equipment
- Bearings
However, cold rolled may be a better choice for smaller bearings because of the product’s more precise sizing. Other cold rolled steel applications include:
- Aerospace components
- Machine parts
Sullivan Supplies Hot Rolled and Cold Rolled Steel
At Sullivan Steel, we stock and distribute a wide range of hot rolled and cold rolled steels; we ship quickly, efficiently, and in any quantity needed. Our experts are experienced with specialty steel grades and work closely with customers to help them get the product that fits their application.
Contact Sullivan to ask us any questions about hot and cold rolled steel or request a quote today.