Does Hardened Steel Rust?

Does Hardened Steel Rust when exposed to moisture or oxygen? Many people are concerned about whether or not hardened steel can rust. With lots of information online, it is becoming quite difficult to know which one is right or not. However, with the question asked earlier, we have an answer for you below.

No, hardened steel does not rust. While all steel and iron-based metals will rust in the presence of moisture and air, some are less susceptible to rust than others. Steels that contain a high level of alloying elements, such as chromium and molybdenum, will resist rusting for much longer than standard carbon and alloy steels.

Also, just because hardened steel is better at resisting corrosion is not completely rust-proof. If you leave your hardened steel tools outside in wet weather for long enough, the moisture will eventually affect them.

In this article, you’ll learn more about hardened steel and its properties that make it rust-resistant.

What Is Hardened Steel?

Hardened steel is high carbon steel that has been subjected to high temperature, quenched, and then tempered. Afterward, it is cooled either by exposure to air, or it is dipped in water, oil, or brine. These processes enable the toughening up of the steel, thus, making them resistant to rust among other things.

What is Hardened Steel

Joseph Glanvill(1636-1680) discovered the basic requirements for the hardening of steel which led to the foundation of hardened steel.

Hardened steel is formed when carbon steel is heated to a very high temperature, subjected to quenching, and then tempered. It is then cooled off either naturally or submerged in water, brine, or oil.

Every year, 85 percent of mild steel falls prey to nature’s woes of oxidation and corrosion. Any exposure of iron to water and oxygen, inadvertently summon rust which strips the carbon steel of its integrity sooner or later.

Yearly, mild steel gets about 0.2 microns of corrosion rate in good conditions while in bad conditions, there is a rate of 20 microns. Although, these statistics vary due to certain factors. That is, it depends on where the steel is located. These factors are soil, pipeline, and marine water.

Properties of Hardened Steel

The processes that lead to the formation of hardened steel call for the evaluation of its properties. It is known to develop a good number of resistant qualities which make it more preferable over regular steel. They are wear resistance, abrasion resistance, durability, and corrosion resistance.

Properties of Hardened Steel

Wear Resistance: Every material or tool designed is subjected to tons of work for which they have been made. It is only natural that these tools undergo wear and tear during work. Hardened steel, however, is an exception. Steel mixed with chromium and subjected to intense heat yields chromium carbide. These particles compactly help to increase wear resistance.

Abrasion Resistance: Its strengthened nature helps to fend off abrasion. Seeing as it is used in heavy-duty machinery. It has the property of standing its ground when it comes to drilling and punching. To cut the story short, it is the miner’s best friend.

Durability: Its heat treatment makes it twice that of untempered oil-heated steel. Because of this, it can last longer placing it as the first choice for engineering machinery.

Corrosive Resistance: Engineering bodies and statistics say that the US spends millions of dollars annually dealing with corrosive issues. Hardened steel is resistant to corrosive chemical components, such as marine water, and atmospheric corrosion. This resistance helps workers worry less about corroding tools of a hardened steel make.

Types of Hardened Steel

Hardened steel is of a few types.

They are

  • Z60CDV14
  • Sandvic 12C27
  • CPM44OV and
  • AT534.

Applications of Hardened Steel

Hardened steel is applied in many fields. Some of the most popular areas it is put to use are transportation, energy generation, and mechanical engineering.

Uses Of Hardened Steel

Hardened Steel has its uses across a vast majority of fields. Seeing as it has a hard exterior and robust core, it is used in the manufacturing of axles, link components, driving pinions, and camshafts.

Hardened steel is also used to make objects that are subjected to high levels of force or abuse. Such as; automotive parts, hand tools, and drill bits.

Frequently Asked Questions (FAQs)

What happens to steel when it is hardened?

When metal is heated at a very high temperature, it is maintained at a certain degree. That degree is then maintained till some level of carbon dissolves. Then hardening occurs. When that happens, it produces alloys that are toughened in strength and resistance. Hardening also causes the metal to be brittle.

Can Mild Steel be Hardened?

Mild steel or low carbon steel cannot be hardened. The low presence of carbon in the steel would not give the desired result should it be subjected to the hardening process.

Why Quench Steel in Oil?

After heating the steel to high levels, there are several methods used to cool down the steel. There is natural exposure, which deals with exposing the steel to air to cool down naturally. Another process is to submerge the steel in either water, oil, or brine. Amongst the three media of quenching, the one most known for transferring heat more quickly is oil. Steel is quenched in it because of the severity it offers.


To further reinforce the facts on hardened steel and in answering the question, does hardened steel rust? Regular mild steel differs from hardened steel. The makeup of hardened steel makes it impervious to attack from rust. Hardened steel is manufactured for heavy-duty types of machinery like drilling machines, rock crushers, and the likes. For it to meet its heavy-duty demands, it is composed of alloys and imbued with peculiar resisting properties. One of them being corrosive resistance.

So, no, Hardened steel does not rust as easily as carbon steel, and it is capable of enduring for a very long time.

Evan Cooper

Evan Cooper

Hi, I’m Evan Cooper, the founder and an editor of this site, Doesitrust. I’m a chemical engineer and working in a rust-eliminating paint manufacturing company. Besides this profession, I’m a researcher and blogger.

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