N690co steel is a fairly common material in the manufacture of knives for blades of cold steel. Due to the well-chosen chemical composition and high quality standards of the manufacturer, knives made of this steel are respected by cold steel lovers all over the world. This article discusses the features of this structural material, its advantages and disadvantages compared to domestic products and foreign analogues.
Steel Manufacturer N690
Steel of this brand is produced by the Austrian company Bohler-Uddeholm. Headquarters and main production are located there. But, besides this, the concern has branches and sales offices in Russia, Germany, and in the countries of North and South America. By the way, in our country the company has placed as many as four branches. This indirectly suggests that Russia is a strategically important and valuable trading and manufacturing partner for the manufacturer.
General characteristics of steel N690
An analogue of this material with approximately the same chemical composition and a set of mechanical and physical properties can be Austrian steel 440C. But in it, the mass fraction of alloying elements (primarily cobalt and molybdenum) is significantly lower. This, of course, affects some important technological properties: the ability to take hardening, the likelihood of developing temper brittleness of the first and second kind, hardness, ductility, and so on. All these properties play an important role in ensuring reliability and increasing the life of cold steel weapons.
One of the most important characteristics of N690 steel is its ability to resist the nucleation and development of corrosion under normal conditions. In addition, as a result of the improvement, the hardness of steel can be increased to sixty Rockwell units (on the “C” scale - the load on the indenter is 150 kilograms).
Many well-known brands and enterprises producing cold steel use N690 steel for the production of knives. Characteristics and reviews from the owners of such knives are extremely positive.
Features of the production of knife steel N690
This steel grade was created and patented by the Austrian company Bohler-Uddeholm as special steel for knives with optimal characteristics. Professional collectors, military and hunters appreciated the characteristics of steel N690. What is the secret recipe that allows you to make material with such a set of mechanical and physical properties?
It is not only the chemical composition, but also the special technology of processing and hardening of the blade. After hardening, the material undergoes deformation (rolling) in different directions. The same technique is used for machining tool high-speed steels in order to break the carbide grid along grain boundaries and reduce the tendency of the material to brittle fracture under significant dynamic loads.
Such processing is also associated with Damascus steel production technology. Although the exact recipe has been irretrievably lost, experts claim that Damascus steel acquired its exceptional qualities as a result of forging from different sides. Although this analogy is not entirely correct: Damascus steel, according to technology historians, was a composite material and was made of two different materials (high and low carbon).
However, the fact remains that the characteristics of the N690 steel fully satisfy the high international quality standards of steel products.
The chemical composition of steel N690
This steel grade contains quite a lot of carbon (a little more than 1%). If it were not for the addition of alloying elements, then this steel would be classified as a hypereutectoid high-carbon tool steel. It is these materials that are used in the manufacture of tools (files, hammers and others).
The high chromium content (more than 17 percent) makes this steel resistant to corrosion. In addition, the hardenability of the material (its ability to accept hardening) is increased and the wear resistance indicators are improved.
Molybdenum (a little over one percent) is introduced to reduce the brittleness and brittleness of the alloy and improves a number of other properties and characteristics of N690 steel. Reviews from the owners of the knives confirm this information.
In addition, the steel melt is additionally alloyed with cobalt (1.5%), vanadium (0.1%), as well as manganese and silicon (each mass fraction is 0.4%).
Classification of knife steels by quality
According to the generally accepted classification, there are distinguished first-class steels, ultra-premium steels, premium-class, high-quality, middle-class, and also ordinary-quality steels.
The assessment of the quality of steel is affected primarily by the presence of harmful and undesirable impurities, or rather, their mass fraction. So, steels that are produced by electric arc remelting in a vacuum will have a minimum amount of non-metallic and harmful inclusions.
Does steel that has a higher grade of purity always have the best performance? No. Not always. It depends on the purpose and operating conditions of a particular product. And although the N690 steel belongs to high quality, it can give odds to many materials of the first class.
Properties of steel N690
Bohler-Uddeholm is a tool steel producer. But of the entire product line, only Bohler N690 steel is alloyed with cobalt. Its characteristics for this reason are an order of magnitude better than others.
The cobalt content in various brands of instrumental does not exceed 5 percent for a tool undergoing significant loads (drills, taps, countersinks and others). If the tool works with relatively soft materials, then the mass fraction of cobalt is 0.3-1.5 percent. Steel grade N690 contains the optimum amount of cobalt to ensure the cutting and strength properties of the knife blade.
An external examination of billets of different types of steel is unlikely to reveal any differences. The difference becomes noticeable only during mechanical tests and when sharpening the blade.
Full-fledged analogues of the steel in question do not exist. Of domestic grades, the martensitic steel 95X18 has the closest chemical composition. As a foreign analogue, X10CrMo17 steel (Germany) and Z100CD17 (France) can serve.