Knife Technology

Hardening is the most important phase in the manufacturing process of a cutting tool. It consists of a heat treatment of the steel at a high temperature (approx. 1070ºC), holding it for a set time (austenitizing time) and then rapidly cooling it to room temperature, thereby transforming the molecular structure of the steel (martensitic reaction), which shows itself as an increase in the hardness of the steel. Hardness is the physical quality needed for good cutting power and edge durability. In addition, the correct internal structure of the steel provides greater resistance to corrosion. ARCOS carries out the hardening heat treatment in continuous controlled-atmosphere furnaces and then performs a second heat treatment, called tempering, which consists of heating to 250ºC to remove any stress created by the rapid cooling of hardening that could make the steel brittle, ensuring the same mechanical properties along the entire edge of the tool.

The forging process consists of deforming the steel, which has previously been heated red-hot, between two tools known as “forging dies”, which are engraved with the shape of the knife to be produced. To achieve this deformation, high-tonnage presses are used, since a strong strike is needed to start the plastic flow of the steel so it deforms and takes the shape engraved in the dies. A key point of this process is that the resulting knife is solid and made from a single piece, avoiding the unwanted welded, glued, or hollow zones that are a hallmark of low-quality knives, because these are areas of low mechanical strength, breakage, and potential points of oxidation.

Direct injection consists of bonding the tang of the knife with the plastic of the handle to create a solid, robust, and inseparable unit. There are no gaps where water or food residue could enter, so it is a fully hygienic process that meets health and safety regulations. The plastic is injected in liquid state (approx. 180ºC) into the mold. The plastic then solidifies around the tang of the knife, forming a single block (blade and handle).

Double injection is a special process to form the handle of a knife, where we use a direct-injection machine with two spindles. This double-injection system lets us use two different plastics in the handle. At Arcos we have developed three series with this technique: Colour Pro, Dúo, and Línea. In these series we inject POLYPROPYLENE on the inner part, a hard material that gives strength and security to the handle-blade bond; and RUBBER on the outer part, a soft and non-hygroscopic material (it does not absorb liquids), which gives the knife a soft feel and an ergonomic shape so it fits the hand and is comfortable for prolonged use.

NITRUM® is the nitrogen-steel formula, eco-friendly and available only in ARCOS knives. NITRUM® provides more hardness¹, greater cutting power², and improves edge durability³. Its new microstructure makes the difference in knife performance, for both professional and home use. The NITRUM® production process respects the environment. Nitrogen is found in the atmosphere, and its enrichment process has no negative effects on air, water, or soil.

High technology for complete bacteriostatic protection in our knives. It involves integrating into the handle a sophisticated silver-based technology, Bactiproof Silver, to stop the growth of bacteria and provide extra hygiene and safety. This system acts as a powerful inhibitor of bacteria, germs, molds, and fungi. In this way, the knife handle has the agents needed to protect the plastic from the appearance of stains, odors, and microorganisms that are harmful to health. In short, it acts as the perfect complement for the kitchen, an environment where hygiene is essential. Bactiproof Silver reduces the presence of bacteria, fungi, and mold on the handle surface by 99.9%. In addition, its antimicrobial performance stays constant throughout the entire service life of the knife.

“ICE-PLUS” SUB-ZERO HEAT TREATMENT The “Ice-Plus” sub-zero heat treatment, applied in the Colour-Prof series, consists of cooling to -80°C after the traditional hardening, with the aim of improving the structure of the stainless steel by removing the small percentage of residual austenite. The resulting steel structure gives the knife special properties, both in impact resistance and wear resistance.

The commitment to continuous improvement that has characterized ARCOS since its founding has allowed the constant innovation of its products. One of these improvements has been the use of stainless steel rivets instead of the aluminum rivets used until now. These new rivets, in addition to improving the assembly of the handles thanks to a greater holding strength, extraordinarily increase resistance to corrosion, ensuring that knife handles never come loose due to this phenomenon.

The Silk Edge was created by combining the knowledge of our master knife makers with the most innovative technology, producing a unique cut with a polished, distinctive finish along the edge. The process is divided into three phases of sharpening and polishing, carried out by hand, resulting in a smooth and precise cut that leaves no one indifferent. Tradition and technology come together to create our special Silk edge, which was implemented for the first time in our Manhattan series and is currently also part of the Brooklyn, Ópera, and Nórdika series.