What Is 1020 Carbon Steel?

Forging molten 1020 Carbon SteelIt’s a good thing that you’re doing your proper research on steels and their qualities, if you’re thinking of buying a knife that’s best suited for your needs. But you must have made a wrong turn somewhere in your research, because 1020 carbon steel isn’t really made for the needs of home users.

It’s not really something you’d use for knifes. You don’t even find this steel in swords, either. And it’s certainly not strong enough to be used for pistol and rifle target shooting.

For the most parts, the 1020 steel is used for industrial and construction components. If you’re a regular consumer, then you’re unlikely to need to buy 1020 steel on your own.

So, what is it really good for? Since you’re already reading this guide, we might as well satisfy your intellectual curiosity…

What is 1020 Carbon steel?

1020 carbon steel refers to steel with carbon steel that contains about 0.20% carbon on average. That’s quite a low level of carbon in the steel, which is why it’s also considered mild steel. It’s not very hard at all, with its low hardenability. It’s possible to nudge up the hardness and strength with some heat treatment, but as a consequence you lower the ductility.

The 1020 steel is quite affordable, and it’s also extremely easy to work with. These are reasons why it’s so popular and versatile. It’s mainly used for simple structural components, and it’s commonly used in a case-hardened condition.

Common Uses of 1020 steel

You can find the 1020 steel used for components such as:

  • Automotive equipment
  • Heavy truck equipment
  • Agricultural equipment
  • Axles
  • Chains
  • Cold headed bolts
  • Pins (especially gudgeon pins)
  • Shafts
  • Camshafts
  • Lightly stressed gears
  • Worm gears
  • Ratchets
  • Spindles
  • For hard-wearing surfaces
  • For case-hardened components (when you don’t absolutely require core strength)

1020 Steel Chemical Composition

This is low alloy steel, meaning a lot of it is pure iron. You have very little when it comes to other alloying elements.

  • Carbon, 0.17% to 0.23%
  • Manganese, 0.30% to 0.60%
  • Sulfur, 0.05%
  • Phosphorus, 0.4%

Carbon, 0.17% to 0.23%: As you can see, there’s not really much carbon here. Carbon content is perhaps the most important when it comes to a steel’s chemical composition, and the low carbon content makes this not quite strong enough for specialized uses (like knives). It’s just too soft.

Manganese, 0.30% to 0.60%: At this level, the manganese is mainly for boosting the surface quality of the steel. In larger amounts, it can boost the tensile strength. It also helps somewhat with its hardenability.

Sulfur, 0.05%: You also want minimal sulfur levels, because it’s not really good for the impact properties of the steel. But with this tiny amount, you do get some good out of this “impurity”. It helps with machinability and with the surface quality of the steel.

Phosphorus, 0.4%: This is another “impurity” that you’d want to minimize in your steel alloy, because it can make the steel brittle. You can, however, tolerate up to just this tiny amount of phosphorus.

1020 Steel Hardness

With so little carbon, it’s not really all that hard at all. That means it’s certainly not good for any consumer items that require a measure of strength, like knives and steel targets for target shooting practice.

Sure, it’s a little bit harder than non-carbon steels. But you don’t use really use this for its hardness at all.

Does 1020 Steel Rust?

Yes, absolutely. It doesn’t have any of the alloys notable for boosting the corrosion resistance, such as chromium or even nickel. This is why it’s used in situations where it doesn’t get wet and then exposed to air. Usually, it’s used in enclosed spaces where the water can’t get at it.

Properties of 1020 Steel

1020 Steel Good for KnivesHere are the main characteristics of 1020 steel:

Great Machinability

That means it’s extremely easy to cut 1020 steel. You get a nice finish, without spending a lot of time and money in doing so. That makes manufacturing a lot easier.

  • You don’t use up a lot of power for cutting.
  • You don’t wear off the tooling much, so your tooling can last longer. That again saves you time and money replacing the tooling to cut the 1020 steel.
  • Cutting the 1020 steel can be done very quickly. That saves you a lot of time, so you’re able to get on with your production schedule quickly. It’s great for high-volume cutting because of the time savings.
  • You get a good finish without much difficulty.

Good Formability

This is the ability of the steel to be formed into the shape you want, without issues like cracking or necking (thinning) coming up. That means you’re able to get it into the shape you want without any trouble, when you’re making bolts or gears. It’s extremely ductile, and you can use all the standard forming methods on 1020 steel.

Good Weldability

Low-alloy steels like 1020 steel are often noted for their good weldability. In fact, the weldability of the steel goes down the more carbon you have in the steel alloy.

Because you only have 0.20% carbon, you rarely, if ever, get problems like cracking when you’re welding the 1020 steel. But it has enough carbon to avoid problems like porosity.

Basically, you can weld the 1020 steel easily, using all the traditional welding methods.

Good Hardenability

You can harden the steel through cold working, or by heat treatment, quenching, and tempering. You can also do forging, hot working, and annealing.

It’s Easily Available

If you need 1020 steel, you won’t find any trouble finding a local source for it to complete your production or construction needs. It’s available in many forms.

It’s Very Affordable

You won’t bust your budget with the 1020 steel, either. The price is very low, which is also great for high volume production and use.

Harder than Non-Carbon Steel

There are cases when you might want to use non-carbon steel, but you can’t because of certain strength requirements. If the 1020 steel meets those requirements due to its hardenability and carbon content, then you’re good to go. You can enjoy all the other benefits (great availability and low cost, etc.,) and still have strong enough steel for your needs.

It’s No Good for Knives and Other Consumer Cutting Tools

It simply doesn’t have enough carbon for cutting. It’s called “mild” steel for good reasons, and that’s because it’s just too soft. It won’t cut anything very well, and it won’t maintain a sharp edge for long.

It’s Not Really Corrosion-Resistant

You don’t use the 1020 steel in situations where it can get wet and then exposed to air.

1020 Equivalent Steels or Alternative

Carbon steelOne of the clearer ways to get to know a particular steel is to directly compare it with somewhat similar steels. That way, you’ll know how the 1020 steel stands among various steels.

1020 steel vs 1010

As you can see in the name, the 1010 has a smaller amount of carbon than 1020 does. The tiny amount of carbon at only 0.10% means it’s not as strong as 1020 steel. But it’s a bit easier to machine and a bit more affordable. It’s also commonly used for cold-headed fasteners and bolts. Still, you may want the strength and ductility that you can find in 1020 steel that you don’t get with 1010 steel.

1020 steel vs a36

The “A36” actually refers to a specific strength level need for the steel, while the 1020 steel complies with more specific chemical composition requirements. In many ways, the steels that meet these requirements are very similar. But in real life, you pick A36 when you have to meet a particular strength level for structural uses. You go with the 1020 steel when it’s deemed strong enough, and you want something affordable and easy to machine.

1020 steel vs 4140

The 4140 steel is much stronger than 1020 steel. With 4140 steel, you get greater hardness, higher fatigue strength, higher shear strength, and greater tensile strength. But if the 1020 steel meets your strength requirements, you’ll find it easier to work with, and more affordable besides.

1020 steel vs 1018

These are very similar steels, with the carbon content almost the same (0.20% vs. 0.18% on average). But the 1018 steel has more manganese to compensate. That’s why the 1018 steel is actually a bit harder, especially after treatment. The 1018 steel has greater tensile strength and yield strength, though the 1020 steel can elongate more before breaking.

Is 1020 Steel Good for Knives?

Oh no, it’s not. Take some time at this point and Google for 1020 steel knives. You won’t find any.

That’s simply because it’s too soft. Maybe you can use the steel to practice your bladesmith skills, but you’ll only end up with a knife (or axe or sword) that’s too soft to cut through anything. And even for smithing practice, you have better steels to work with.

Pros & Cons of 1020 steel

  • It’s easily available
  • It’s no trouble to work with, with great machinability, formability, and weldability
  • It offers better strength and hardness compared to non-carbon steels
  • It’s very affordable
  • It’s not much use for consumer cutting tools, like knives, cutlery, or even swords and axes
  • It’s not really resistant to corrosion


Industrial manufacturers use 1020 steel for certain components, simply because it’s very easy to work with and it’s quite affordable. It also contains carbon, and even its small carbon content makes it stronger than many non-carbon steels.

But you won’t find regular consumer items made solely with 1020 steel. Sure, you may have bought some items (like electronic appliances) where there are some components made with 1020 steel. But you won’t find knife blades made with this, or even axes and swords. It’s just too soft. Unless you’re an industrial manufacturer, you won’t really work or use 1020 steel all that much.

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