Discover The Difference Between Hot and Cold Rolled Steel

It’s surprising how many people that approach us for a quote for the material costs of producing a product, don’t know the difference between hot and cold rolled steel. The difference isn’t in their grade but in the way they are processed at the mill. When you’re choosing metal for a job then it’s important that you understand the different processes and consequently can make an informed decision on which metal to choose.

So, first of all what is the rolling process?

Rolling is a process involved during the forming of metal and involves the metal going through one or more pairs of rolls to make it thinner. The rolling process makes it more uniform in thickness, a bit like rolling out pastry in your kitchen.

When the rolling is carried out above a certain temperature it stops the steel from becoming crystallised again, and this is called ‘hot rolling’. On the contrary, metal that’s rolled below a certain temperature allows it to recrystallise, and this is referred to as ‘cold processing’. Roll stands hold the pairs of rolls and since they’re grouped into the rolling mills, they’re able to process the metal into products quickly and efficiently.

Hot rolling

This is performed at a temperature in excess of 1700 degrees Fahrenheit which is above the temperature at which the steel would otherwise recrystallise. Because it makes the steel easier to shape and form, it’s also possible to create much larger sizes. As a rule it’s less expensive than the cold rolling process since it can be completed in a day.

Hot rolling is typically used to produce sheet metal and simple cross sections. These are normally used for such things as

• Agricultural equipment

• Metal buildings

• Water heaters

• Wheel rims

• Strappings

• Truck frames

• Railway components

• Stampings

Cold rolled process

During the cold rolled process temperatures are closer to room temperature and the process actually strengthens the steel by as much as 20%. This increase in strength comes as a result of strain hardening and produces a grey finish which is smooth to the touch. This particular product is typically only made into a few shapes such as square, flat, or round. If additional shapes are required then various shaping options would be necessary.

We recommend the use of cold rolled steel for products such as

• Home appliances

• Shelving

• Metal furniture

• Exhaust pipes

• Chairs

• Tables

• Water heaters

Know what you need

Before setting out to buy high quality metal products have in mind how you’re going to be using that product. It’s the end result that you’re seeking which will determine the type of rolled steel that you need. You’ll also need to know if it will need sizing or shaping.

Larger materials which are to be made into distinct shapes will need the hot rolled metal process whereas smaller products which need to be durable and tolerant, will need the cold rolled metal process. If you’re unsure which process is best for your project then we can give you expert advice and suggestions. Understanding the difference between the two processes and knowing which works best for your project can save you time and money and give a better result.

Get in touch

If you’re planning a steel project then come and talk to the experts at Metro Steel. You can call us on 07 3204 1000 or call in and see us at our purpose built premises at Kabi-Circuit, Deception Bay. We look forward to working with you