Details CPM Rex 45 Steel Review

What is CPM Rex 45 Steel, you ask?

CPM Rex 45 steel has 8% Cobalt as its composition. It is a popular steel in Europe, Japan and Asia. Rex 45 is the same chemical composition of M3-2, but with Cobalt.

Cobalt increases the hardness CPM Rex 45, even at red heat temperatures. This steel is very durable and has excellent edge retention.

CPM Rex45 can be used to make cutting tools, blades and cold-working tools. Rex45 steel can undergo other treatments depending on its usage to enhance its quality.

They diffuse Nitrogen and Carbon on the metal to aid in nitriding. This results in greater corrosion resistance and strength.

CPM Rex 45 Steel Composition

  • Carbon 1.30%: Enhances edge retention, hardness, and tensile strengths. It increases steel resistance to wear and abrasion as well as corrosion.
  • Chromium Cre 4.05%: Formation Chromium carbides Enhances hardness, tensile force and toughness of blades
  • Molybdenum Mo 5.0%: It increases machinability, hardness.
  • Vanadium V 3.05% – Increases wear resistance and toughness. It also improves corrosion resistance. Vanadium carbides can be formed when there is a high vanadium content.
  • Cobalt Co 8.0%: It improves the hardness of the blade by increasing the martensitic transform temperature of the alloy. It also increases steel’s resistance to corrosion
  • TungstenW 6.25% Increases wear resistance, hardness, and is most commonly added to tool steel
  • Sulfur S 0.06%: Helps improve machinability, grindability.

Steel Rex 45 properties

CPM Rex 45 Steel Hardness

Rex 45 steel’s hardness is dependent on how it has been treated, but it can reach a maximum Rockwell hardness level of 67 HRC according to the Rockwell hardness scale. The steel’s high hardness is due to its 8% cobalt content.

Rex 45 Steel Toughness

Toughness is the steel’s ability to resist breaking, cracking and chipping under stress and impact. Steel that isn’t tough is considered brittle. The steel world is tougher because steel’s hardness decreases with age.

CPM Rex 45, a very hard steel is not expected to be tough. It does offer decent toughness. High-quality knives blades are made from steel types that have a good balance between hardness and toughness.

The lack of high amounts of chromium carbide, which can lead to brittleness, improves Rex 45’s toughness. The REX 45 knives are perfect for tough applications.

Wear resistance for Rex 45 Steel

REX 45 is extremely wear-resistant due to its high hardness. CPM REX 45 knives will last a lifetime because they are not easily damaged by daily use and sharpening.

Rex 45 Steel Edge retention

Edge retention is another area where REX 45 excels. Rex 45 steel blades have superior edge retention. This means that you don’t have to sharpen your knife every time, which can save you both time and effort. Rex 45 edges retain slightly better than M4 and their only difference is the hardness level.

Rex 45 steel is more durable than any other steel. It has a lower edge retention and will outperform all steels. REX 45 knives are the best choice if you want a knife that will keep its edge for a long period of time.

Rex 45 Steel Corrosion Resistance

REX 45 steel does not have the same corrosion resistance as stainless steel. It does not contain enough chromium to make it stainless steel, so it needs extra care to prevent corrosion.

REX 45 knives will not work if you’re looking for knives that can be used in extremely corrosive environments. If the knives meet your requirements due to their exceptional hardness and wear resistance, you can still make a purchase.

To prevent rust and stains, ensure to properly maintain your knives by washing them and drying them after each use.

Rex 45 steel knives can quickly develop a patina. Some knife users prefer to force Patina to their Rex 45 blades to prevent rusting. Although the patina of most Rex 45 steel is stunning, it all comes down to personal preference.

Sharpening Rex 45 Steel

REX 45 is a hard steel, so it will be difficult to sharpen. REX 45 is much easier to sharpen than other high-end steels. You can achieve a sharper edge quicker if you have the right tools and skills.

REX 45 steel comparison

CPM REX 45 vs. CPM m4

Rex 45 steel has a lower Carbide volume than M4 steel. This is due to the higher amount of vanadium elements in M4 alloy. Rex 45 steel is more durable and resistant to wear than M4. REX 45 excels in hardness and edge retention and is much easier to sharpen.

Both sheets of steel can be rust-resistant, but they are not stainless steel.

CPM REX 45 vs.

REX 45 is better steel than M2 in all aspects. It has a higher hardness, toughness, and wear resistance. This steel is also more sharpenable. Both offer low corrosion resistance, so they are not good choices for knives that will be used in corrosive environments.

CPM Rex 45 vs. M390

M390 steel is three times as carbide-rich as Rex 45 steel and is also stainless. It has a higher corrosion resistance than Rex 45 steel. Rex 45 steel may be more effective at edge retention than M390 steel, even though it has a lot of carbides.

This is due to M390 having more chromium than vanadium carbides. Vanadium carbides have the best edge retention and hardness. Therefore, you should look for knife steels with high vanadium carbide volumes.

CPM Rex 45 vs. K390

Steel Rex 45 has a higher Rockwell Hardness than k390 steel. Both sheets of steel perform in the same ball pack. Both steels retain their edge well, and only the hardness of each will make a difference. Rex 45 steel is slightly better in edge sharpness, but not by a significant margin.

Both offer a similar level of toughness so that you can get great performance with both. Because they have a low level of chromium, they aren’t as corrosion-resistant as stainless steel.

CPM Rex 45 and Maxamet

CPM Rex 45 steel is extremely hard with a Rockwell hardness of 67 HRC. Maxamet steel from Spyderco, however, outperforms it with a remarkable hardness of 70 HRC. This is due to its high Vanadium content. CPM Rex 45 steel is beaten by Spyderco Maxamet in edge retention, toughness, and wear resistance due to its fine microstructure of vanadium carbides.

They will need to be treated with extra care as they are not considered stainless steel. Maxamet Steel is a little more difficult to sharpen than Rex 45 steel.

Is REX 45 good knife steel?

CPM REX 45 knife steel is a good choice because of its excellent hardness, edge retention and wear resistance. Rex 45 steel knives are very hard and extremely resistant to wear due to the addition of cobalt, tungsten and tungsten to its alloy.

Few sheets of steel can match Rex 45 steel’s hardness. Maxamet steel from Spyderco, however, is one of the few.

It isn’t stainless steel and, therefore cannot be used in highly corrosive areas. This is the main problem with Rex 45 steel. It is a great knife steel if it is well maintained.

About the author

Hi, my name is Jaba Ray. I'm a knife expert and researcher. I am the creator of, your one-stop site for everything related to knives. I love people who need suitable steel or knife for their cook because I'm also a food lover. I work with a team of people who've always had a passion for knives and blades on this site.

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