If you’ve ever needed construction components or custom steel parts, you may have asked, “What’s the difference between hot rolled vs. cold rolled steel?” These are two standard methods of steel sheet and bar production, each offering distinct characteristics.
Goto Xingtai Steel to know more.
Each has unique structures and best-use applications, so understanding these differences is vital to deciding the appropriate type of steel for your project. Whether automotive or manufacturing, knowing which type of steel to use can impact the quality, durability, and cost-effectiveness of your work. In this comparison guide on cold rolled vs. hot rolled steel, we’ll cover everything you need to know to help you make informed decisions for your specific needs.
When learning the difference between cold rolled and hot rolled steel, you must compare their physical properties and ideal-use cases. Factors such as processing costs, weldability, and surface finish all play a role in determining which type of steel is best suited for your project. For each of the various factors to consider, we’ll compare hot vs. cold rolled steel.
Cold rolled steel is one of the strongest types of steel available. It’s often used in aerospace structural components after additional hardening treatments to reduce deformation risks.
Even though cold-rolled steel is superior in strength, hot-rolled steel has a higher stress tolerance because it’s cooled slowly at room temperature. Cold-rolled steel isn’t manufactured at high temperatures as hot-rolled, making it weaker in tension resistance. It’s why post-processing hardening treatments are required to enhance cold-rolled stress tolerances.
Hot rolled steel is designed for durability and strength because it can be put under high-stress applications without wear and tear. The automotive industry often uses hot rolled steel applications for vehicle frames because of its power to withstand high-stress applications.
Hot rolled steel is known for its malleable properties, which simplifies the welding process compared to cold rolled steel. Both hot and cold rolled steel are manufactured using similar initial processes; however, cold rolled steel undergoes additional post-processing steps. Despite these differences, each type of steel has its specific advantages depending on the requirements of the project at hand.
Since cold rolled steel has a lower stress tolerance to work hardening than hot rolled steel, more processing is required to reduce warping from internal stresses in heavy-use applications. Although cold rolled steel is one of the strongest types of steel, it can warp if overworked. To strengthen its tension- resistance, it goes through rollers at room temperature after initial processing.
Due to their weldability and processing differences, cold rolled steel costs are higher than hot rolled steel. The average price of a cold rolled steel sheet is over $400, and a hot rolled steel sheet is around $270.
When hot rolled steel cools, it becomes distorted through shrinkage, rounded edges, and scaling. However, it has a higher stress tolerance to work hardening once cooled than cold rolled steel. Hot rolled steel is wear and corrosion-resistant under heavy-use applications.
The food and beverage industry commonly uses hot rolled steel in dinnerware because precision isn’t prioritized, can be subject to heavy use without damage, and is more cost-effective than cold rolled steel. Although cold rolled steel is one of the strongest types of steel, there are warping risks if it’s overworked from internal stress.
Unlike hot rolled steel, cold rolled steel isn’t subject to distortion during processing with sharper edges and no scaling. Cold rolled steel is known for its smooth surface properties. Industries prioritizing appearance and functionality opt for this steel option because of its precision.
The automotive industry commonly uses cold rolled steel for smoother body part aesthetics. The food and beverage industry also uses it for food-processing appliances for its smoother surface. Aerospace sectors also opt for cold rolled steel for aircraft parts due to its precision and lack of distortion.
So, when deciding between hot rolled vs. cold rolled steel, which option is better? Unfortunately, there is no straightforward answer, as whether cold rolled or hot rolled steel is superior depends largely on the specific application. Each type of steel offers its own unique advantages, disadvantages, and best-use cases, making it important to carefully consider the requirements of your project. Understanding these differences can help you make a more informed decision on which steel type will best meet your needs.
When determining if hot rolled vs. cold rolled steel suits you, consider their physical properties and how they impact how you need it to function. Cold rolled steel is ideal if your project requires sleek appearances and superior strength. Hot rolled steel is your best bet if you need a cost-effective option that can withstand heavy applications without damage.
Here at H&K Fabrication, we have a wide range of pipe welding tools that’ll make your pipe welding projects easer and more efficient. If you’re in need of quality welding tools for your pipe welding projects, you can find anything you might need here. From Roll Out Wheels to Pipe Fitter Squares, we’ve got you covered.
What is Hot Rolled Steel?
Hot Rolled Steel is steel that has been heated to at least 1,700º Fahrenheit, where is is processed and rolled at these high temperatures where it is more malleable.
What is Cold Rolled Steel?
Cold Rolled Steel is when the steel is processed and rolled at room temperature, rather than extremely high heat. This process required much more pressure, as it is not nearly as malleable at cooler temperatures.
Is Hot Rolled or Cold Rolled Steel stronger?
Cold Rolled Steel is stronger than Hot Rolled Steel, however, it does have a weaker stress tolerance than Hot Rolled Steel.
I was wondering if there was any views on the suitability of using black hot rolled steel (HRS) as the basis for machining a slotted cross slide about 8 inches by 3 by1.
Cast iron would be preferable but always seems very expensive (>£50) rolled steel would be about £10. I am unable to heat treat so can't use BMS and I don't fancy fabricating a table, leaving HRS.
I would treat the rolled steel similar to cast iron, taking a deep cut with a carbide face mill all round to get rid of scale, then take approx. to size, then mill the slots and v-ways then mill the tees, then finish mill the surfaces (or grind on my Stent if I have to.
Is this sort of work feasible with this material? will it do as the 'poor mans' steel / iron and are there any common issues, risks or other things to be aware of when generally working with HRS?
Ta
Martin.
I use a lot of hot rolled steel, both for my traction engines and for tooling. It has a number of characteristics, some good, some bad:
It is rather sticky and has a propensity to tear if speeds and feeds are incorrect. I use carbide tooling as a matter of course for turning and milling. Run fast and you'll get a good finish. It won't look like free cutting steel but is still fit for purpose
Are you interested in learning more about hot rolled steel bar? Contact us today to secure an expert consultation!
I don't worry about the scale, it's not like the hard surfaces on a casting
The material doesn't go banana shaped when you mill it
It doesn't seem to be prone to rust like free cutting steel. I get a great finish on EN1A, put it on the hall table and the next morning it shows signs of rusting. Hot rolled doesn't do that, it survives in the kitchen without rust, and the kitchen isn't exactly dry.
Hot rolled steel is good in tension and compression unlike cast iron.
This is part of press tool set I've just made from hot rolled steel:
Andrew
Hot rolled is one of my go to materials in the shop as it is easy to source. I like machining it (it takes a bit to get adjusted as indicated above).
Just make sure you size your material to allow for cleanup. Most hot rolled sections aren't all that square so you have to remove a fair bit of material to clean it up. Obviously cold rolled doesn't suffer from this problem but it suffers from residual stresses.
For most home shop tools hot rolled works quite well.
Just be warned if you wish to scrape the slide in for fitting purposes, scraping steel can be miserable compared to cast iron. If you are going to scrape I would spend the extra money on the cast iron.
Thanks to all that replied, very helpful and useful to know that this is material OK for general use, also useful to know that high speeds and low feeds are the way to go. I now feel emboldened to give the project a try. And if it all goes pear shaped, at least it wont break the bank!
As the project is only for home mini lathe use, the ultimate in high finish and durability is not really necessary. I hadn't thought about scraping issues but I wouldn't have thought it necessary for this application.
AdrianR – you ask an interesting question, I always thought in my ignorance that anything described as 'black steel' by stockholders was technically the same as hot rolled steel. Somebody please shout and tell me quickly if this is not the case!
I don't know of any helpful steel stockholders near to Weston that are willing to supply small quantities so was going to use M Machine Metals, but only because I have used them before (other stockholders are available).
Thanks to all,
Martin
Larry, not much 'raw' material is really round but I use my 3-jaw for holding all types of materials. However – you have to skim it true and then not remove it from the 3-jaw once trued (or it will not run true when replaced). A 4-jaw is useful when something that has already been 'trued' (by turning or grinding) needs to be set-up to run true (often for a second operation for instance).
If I have a piece of rod that I'm going to machine down – I'll generally just stick it in the 3-jaw, because it's quicker and simpler to do so. The 4-jaw generally gets used when I have something awkward to hold or where I need to set it to run true or (alternatively) have it run off-set (eccentrically).
So I think (and my apologies if I've misunderstood your question) the answer would be No – your 3-jaw chuck will normally be fine for hot-rolled rod.
Regards,
IanT
Edited By IanT on 06/04/ 13:38:56
For the less pecunious of us, often using "pre-loved" metals, hot-rolled steel has the advantages of stability described above, and you are less likely to be caught out by some nice shiny stuff from the local scrap-yard being anything but free-cutting!
It is also usually readily welded, which is not recommended for leaded free-cutting steels. (EN1A will fuse, but the welds can be brittle.)
Recently I made a set of dovetail nuts to hold the magnetic read-out strip to my milling-machine table, using the slot that originally held the limit-stops. I saw this is the only practical way, on a Myford VMC mill not designed to take a DRO set. My stock was cut from old miniature-railway rail, flat-bar not profiled, scrapped as too worn and rusted for continued railway use. The worst corrosion pits were quite deep, but the nuts are sufficiently thinner than the stock to avoid them.
Years ago I worked as materials store-keeper for a manufacturer of industrial screen-printing machines, when it received a one-off order for special jigs to hold long surveying-poles for printing their rule scales (not ruler – I've read that thread!). The longest was at least 2m long, and after the miller had cut the requisite facings and channels along the BMS stock, it naturally warped. So it went off to a heat-treatment firm for normalising, but came back even more normally bent. I can't remember what they did eventually – might have used aluminium-alloy instead.
A further tip:
Those DRO nut's dovetail chamfers are at 45º. No suitable cutter, so I drilled and tapped all the holes regularly-spaced along the strip, then drilled matching holes along a piece of angle-steel, at the same settings. Screwed the nut-strip to the angle, clamped that to the mill table so it acted as an inside-out V-block; then kept the assembly together to hold in a vice for junior-hacksawing the nuts apart.
I marked the cuts first by tiny drill-spots during the drilling and tapping process: the nuts' ends do not need be more square than by eye, and a file soon tidied them.
Note: this process order will not work in all cases. What surprised me, when at the printing-machine manufacturers, was the number of times millers making extra T-nuts would drill and tap all the holes in a bar length then expect me to separate them on an auto-feed hacksawing-machine with a well-made but poorly-designed geared-roller vice. It was definitely not for such tasks and incapable of holding short bars anyway. I had to gently suggest to these apprentice-trained, skilled machinists that the repetition would be far easier and more reliable if I cut the embryo nuts from the stock bar before machining.
If you are looking for more details, kindly visit hot rolled round bar.