Surface and Heat Treatment of Metals

KUCHLY company is able to perform several finishing processes on both parts and production tools. We are capable of carrying out controlled environment quenching operations. We are also equipped with tribofinishing machines to eliminate any risk of sharp edges related to the punching of parts. We can also offer coatings that protect against corrosion such as zinc plating, hot-dip galvanization, or that improve weldability or conductivity such as pure tin, silver plating, or gold plating.

Tribofinishing

Tribofinishing consists of impacting the exterior surface of metal parts with more or less abrasive stones of various shapes for a given time depending on the desired objective. The two main purposes are either modifying the metal surface by decreasing the Arithmetic Roughness (Ra) or eroding the cutting edges by inflicting repeated impacts with abrasive stones. A third underlying function allows, in addition during this tribofinishing operation, to wash the parts as a small amount of water and detergents are necessary for carrying out these operations. Following this tribofinishing operation, we perform a drying operation on the parts.

Electrolytic Surface Treatment for Anti-Corrosion or Conduction

Different metals may require a coating to protect against oxidation, corrosion or to “increase weldability or conductivity. E” lectro-zinc plating is a process during which zinc is deposited by electrolysis. The part to be protected is the cathode here and the zinc source acts as the anode. The zinc is in oxidized form and transformed into ions dissolved in an electrolytic solution. These zinc ions are then reduced to metallic zinc at the cathode and thus deposit, creating a superficial layer of zinc. The obtained oxidation-reduction is as follows: Anode: zinc oxidation: Zn -> Zn 2+ + 2e Cathode: zinc reduction: Zn2+ + 2e- -> Zn

The “thickness of deposited zinc can be adapted to the” application by controlling both the current imposed on the electrolytic system and the exposure time and can vary between a few microns to less than 50 μm. There “is no diffusion between the zinc and steel layers. E” lectro-zinc plating reaches its limits when dealing with “a hollow part because the zinc deposit will only be” on the “outside of the part and not observed on the” inside of “a tube, for example. In these cases, hot-dip galvanization should be preferred. O” ther coatings are possible with the same electrolytic deposition process such as “tin plating, s” ilver plating or gold plating.

Surface Treatment by Hot-Dip Galvanization

Hot-dip galvanization is a method that combines two types of protection, physical by coating the part, and chemical by providing zinc which will act as a sacrificial metal. Hot-dip galvanization is a process that consists of coating metal parts by immersion in a bath of molten zinc.

The treated parts can be made of steel, gray cast iron, or ductile iron. The obtained coating protects the part by creating a physical barrier between the external environment and the substrate, but also by cathodic protection (consumption of the zinc coating instead of the substrate). When steel is immersed in a molten zinc bath (at a temperature > 419°C), after cooling, a series of alloy layers (intermetallic compounds) with decreasing iron content is observed on the steel surface as one moves away from the base steel.

These intermetallic compounds give the coating perfect adhesion and exceptional resistance to impact and “abrasion. Generally, the formation of alloy layers is rapid (a few minutes) and the coating thickness (50 to 70 microns) no longer increases, even if the immersion time is prolonged, except in the particular case of so-called reactive steels. The” advantage of hot-dip galvanization is the protection of all the porosities of the parts to be treated, unlike spray processes.

Surface Treatment by Powder Coating

Powder coating protection involves applying an epoxy or polyester powder to the parts using an electrostatic gun to cover the entire piece. A polymerization operation necessarily follows this temporary powder deposit to make it permanent.

For this purpose, the parts are placed in a curing oven at 200°C to obtain polymerization of the powder. These coatings provide both color and a final appearance – matte, satin, or glossy – to the part while protecting it against oxidation and thus rust, as well as against impacts.

Heat Treatment of High Carbon Content Metals

For heat treatments, we are able to perform in-house steel quenching of Type Z160 (X153CrMoV12) under controlled conditions. We also perform the necessary tempering for the implementation of cutting, bending, and stamping dies to achieve hardness levels of 58 to 60 HRC. The fact that quenching and tempering of metals are integrated into “KUCHLY company gives us great reactivity in case of the need for remanufacturing a part of” a tool.

We also specialize in powder metallurgy steels such as Vanadis 8, T.S.P.3 W or equivalent, which are a combination of several materials in powder form, typically 2.3% Carbon (C), 0.4% Silicon (Si), 0.4% Manganese (Mn), 4.8% Chromium (Cr), 3.6% Molybdenum (Mo), and 8% Vanadium (V) to achieve a hardness of 64 HRC after metal processing. This type of assembly, combined with vacuum quenching and multiple tempering, allows us to obtain high wear resistance necessary for cutting stainless steels or tools used in large production runs.

We also work with XC78 LC quench and tempered steel or equivalent to produce series parts such as springs, clips, or others on which we perform oil quenching operations followed by a surface metal processing such as zinc plating or other.