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Steel Z90 ( France)

Steel Z90 (Z90CDV18) is a high-carbon stainless alloy created by the French metallurgical industry, which has high hardness, wear resistance and ductility. It is actively used in the knife industry. It is classified as a high-quality steel for making knives in the budget and mid-range segment.

Specifications:

Z90 is a corrosion-resistant chromium steel produced by the French Association Francaise de Normalization (AFNOR). This alloy, like its many analogues, including the domestic steel 95 × 18, is widely popular and is actively used in knife production.

The characteristics of the Z90 depend entirely on the quality of the hardening. With the correct technology, it is possible to achieve optimal performance for creating cutting tools. So, the hardness of the metal is in the range of 57-59 HRC, which is the most suitable value at which a high level of strength is achieved without loss of elasticity, some manufacturers bring this value to 60-62 HRC, but then there is a great risk of making the alloy too brittle.

Steel has undoubted advantages: 

• Good resistance to corrosion and chemical processes due to its high chromium and vanadium content.
• Excellent toughness is an important characteristic, which means that the blade will not break even under strong mechanical stress, for example, if it is thrown into wood or struck against another metal.
• Affordable cost, allowing the Z90 to be attributed to the middle price segment, while the quality of this steel is an order of magnitude higher than that of many competitors - an important plus in modern realities.
• The alloy composition includes various alloying additives that optimally balance its characteristics.
• Hardness 57-59 HRC is almost ideal, it combines strength and flexibility.
• The Z90 makes all-round knives that, thanks to their properties, are able to cope with any daily task.

But there are also disadvantages:

• Metal processing is rather difficult due to its high hardness. It is not easy to sharpen a knife - a significant disadvantage at home, however, it dulls much longer.
• Sometimes, depending on the manufacturer, it turns out that the Z90 composition in excess can be burdened with phosphorus and sulfur, which negatively affect all positive properties.
• Many blades made of this steel have increased fragility, so it is better not to take risks and not use them for working with very hard materials.

Chemical composition

Composition of Z90 CDV18 steel in percent:    

• Carbon affects the hardness of the metal, but its high content makes the structure brittle;
• Chromium determines the resistance of the alloy to corrosion processes;
• Molybdenum increases hardenability and has a positive effect on wear resistance;
• Phosphorus and sulfur are harmful additives used in production technology; outside the norm, they significantly reduce the characteristics of steel;
• Vanadium increases strength, service life and toughness;
• Silicon removes unnecessary oxygen bubbles from the composition, making its structure homogeneous.

Analogs

One of the closest analogues of the Z90 in terms of its properties and chemical composition is the domestic steel 95X18. Most of the Russian blacksmiths and large manufacturers, for example, "Zlatoust" actively use it in the production of knives, which is not at all surprising. Blades made of 95X18 have a number of positive properties:

• high level of wear resistance;
• increased strength;
• hardness;
• neutral reaction to aggressive media.

When you choosing a knife, which can be folding or fixed, hunting or fishing, urban EDC or tactical, camping or survival knife, you must first pay special attention to the type of steel used on the blade. Along with the geometry and design of the blade, the blade material is the critical element that determines how the knife will perform.

1) REMAINING ELEMENTS OF STEEL ALLOYS 

Primitively speaking, steel is an alloy of iron with carbon. If there is too much carbon, then cast iron is obtained. If too little, then it is called tin. Anything in between can be called steel. Its various types are determined not only and not so much by the proportions of iron and carbon, but by alloying with various additives and impurities that give different properties to steel.

Carbon: Present in all types of steels as a basic element that imparts hardness and rigidity. Most often we expect a carbon content of more than 0.5% from steel (these are the so-called high-carbon steels)

Manganese: An important element of the alloy, it gives the metal a grain structure, and contributes to the strength of the blade, as well as rigidity and wear resistance. It is used to improve steel during rolling and forging (so-called "deoxidized steel"). Present in all blade steel alloys except types A-2, L-6, and CPM 420V.

Chromium: gives the alloy wear resistance, hardenability, and most importantly, corrosion resistance. Steel with a content of at least 13% chromium is called "stainless". Although, despite this name, any steel can corrode if not cared for properly.

Molybdenum: a hard-melting element, prevents blade brittleness and brittleness, gives resistance to heat. Present in many alloys. The so-called "air hardened" steels contain at least 1% molybdenum, which makes this type of hardening possible.

Nickel: Used for hardness and corrosion resistance as well as alloy toughness. Present in steels L-6, as well as in AUS-6 and AUS-8.

Silicon: Used for the strength of the blade. Just like manganese, it is used in blade forging.

Tungsten: gives the blade a wear resistance. When combined with chromium or molybdenum, tungsten makes steel "high speed". This steel grade M-2 has the highest tungsten content. Also used in the manufacture of tank armor

Vanadium: contributes to wear resistance and strength. Hard-melting element of increased hardness, which is necessary in the manufacture of fine-grained steel. Many alloys contain vanadium, but its highest content is in the M-2, Vascowear grades, as well as CPM T440V and 420V (in decreasing order of vanadium content). Steel BG-42 differs from steel ATS-34 mainly in the addition of vanadium.

2) STAINLESS STEEL

Remember that any steel can rust. But the so-called "stainless" steels, due to the addition of at least 13% chromium, have significant resistance to corrosion. At the same time, it should be noted that one percentage of chromium is still not enough for the recognition of steel as belonging to the category of "stainless". In the knife industry, the de facto standard is 13% chromium, but the ASM metal guide says "more than 10%" is sufficient; other sources set their own quantitative boundaries. We add that alloying elements are strongly influenced by the chromium content; a lower proportion of chromium with properly selected other impurities can give the same "stainless steel" effect.

Quality care as a necessary part for all knives????

No knife is designed to stand up to improper care. It is obvious, that you want to ensure that you’re doing everything you can to keep your tool in the best possible shape. By cleaning your knife and caring for it properly, you’ll extend its life and ensure optimal performance for many years to come.

Read through to know the ways through which one can maintain and take proper care of their knives.

1) Cleaning Your Fixed Blade Knife

When cleaning a fixed blade knife, it’s important to take care not to use harsh, abrasive cleaners. The stainless steel surface of your knife’s blade may be coated with DLC (Diamond Like Coating), ZrN (Zirconium Nitride), or it may simply be an uncoated CPM (Crucible Particle Metallurgy) S35VN steel or something similar. In either case, using a harsh cleaner could either remove the finish or damage the steel of your knife, and we don’t recommend it.
Instead, simply use a mild soap and warm water to clean your fixed blade knife. Also, be sure that you use something soft and non-abrasive for this task, such as a cotton cloth or the non-abrasive side of a sponge. Using an abrasive scouring pad, steel wool, or any other highly abrasive material will likely scratch the coating (or the uncoated stainless steel finish) of your knife.
For sticky or gummy substances (such as tree sap, tar, and so on), first use a cloth with acetone to remove the residue in question. Wipe the knife clean, and then be sure to follow the instructions below for oiling to protect the finish.
Once your knife has been cleaned, be sure to dry it thoroughly.
Don’t forget to exercise caution when handling your knife for cleaning.
Oiling Your Knife

2) After washing and thoroughly drying your knife, it’s time to oil the blade. Applying oil to your blade will help to disperse any remaining water and seal the blade from moisture, which will help to eliminate both unsightly water spots and any potential for rust. Using a chamois cloth, apply a small amount of oil such as WD-40 to your blade. This will serve to both protect your blade and give it a clean, shiny appearance.
How to Properly Store a Knife

3) If you’re carrying your knife with you on a daily basis, you’ll likely have it in a sheath of some kind on your person. If you own knives that you don’t use regularly, though, it’s important to store them properly once they’ve been cleaned.
When storing your knife, be sure to place it in a low humidity environment of some kind. If your knife is in a case, drawer, or cabinet, placing a dessicant of some kind (such as a silicone gel pack) next to the knife will help to ensure that moisture doesn’t settle onto the blade. Generally speaking, we also recommend oiling your knife a couple of times per year if it’s in long term storage and isn’t seeing regular use.
If you take care of you knife, it will serve you well for years to come.