Cemented Carbide Coated Tool Coated Substrate Gradient

The bonding strength of the coating and cemented carbide coated tools alloy matrix is key carbide tool life, the coating must be suitable substrates therewith can combine to achieve the desired performance. Not the same material as each of the thermal expansion coefficients are different, probably because of the thermal stress cracks in the coating during cooling. Due to the brittle cemented carbide coated tool coating material, usually easier to crack the coating to the substrate surface extension. Gradient of substrate processing, the surface area of the coated substrate forming ductile region cubic carbides and carbonitrides, the binder content in this region is higher than the nominal binder content of the coating substrate; when the coating formed when the crack growth to the region, because of their toughness, crack propagation can absorb the energy, it is possible to effectively prevent the crack to the inside of the alloy expansion, improve the performance of cemented carbide cutting tools.

Preparation Cemented Carbide Coated Tool

Preparation cemented carbide coated tool varied, its methods are vapor deposition, thermal spraying, chemical treatment, thermal reaction diffusion deposition, sol-gel. Is a method commonly used in the preparation of vapor deposition, because the preparation of the coating quality is good, has gradually become the dominant tool coating preparation methods, vapor deposition, chemical vapor deposition technology is divided into (chemicalvapordeposition, CVD) and physical vapor deposition (physicalvapordeposition, PVD). Chemical vapor deposition (CVD) deposition category belonging atom, a pioneer in the use of gaseous reactants through the atom generated solid coating, intermolecular chemical reaction pathway techniques.

Cemented Carbide Coated Tool Heat Treatment

Heat quantity cemented carbide coated tool because it is in an arc ion plating process, the substrate temperature between 200 ~ 400 ℃, due to the lower temperature, the coating material is deposited on the substrate surface is quenched, the coating material due to the thermal expansion coefficient differences have different heat shrinkage tendency, between the coating of each grain thus generating a thermal stress. The existence of thermal stress accelerates cemented carbide coated tool failure in mechanical cutting process. The heat can absorb part of the strain energy, easing the stress relaxation, coordination of the corresponding state change. Heat-treated steel base CVD-TiN coating, the coating after 1030 ℃ 250 ℃ after quenching and tempering, TiN coating microhardness increase, the crystal structure of the coating tends to be more complete, its lattice spacing and more TiN crystal plane close to the standard value of the pitch, while the density of the coating increased, and a good combination of strength of the matrix.

Cemented Carbide Coated Tool Cold Treatment

Cemented carbide coated tool, the composition and nature of the binder phase matrix Co tool for strength and deformation characteristics of cemented carbide coated tool plays a vital role. If you want to change the characteristics of this ingredient and alloys, has two ways, one is the heat treatment, another is the tool cold treatment. Cold treatment cemented carbide coated tool creates a ultra-low temperature environment, the degree of supercooling is increased, so that the cobalt alloy free energy difference of the phase change increases, increasing the driving force of phase transition, thereby reducing the tool in the cutting process abrasive wear and diffusion wear. Because of the higher surface hardness and wear resistance coating material, cemented coated carbide allows a higher cutting speed, thereby improving the processing efficiency; or can greatly improve tool life at the same cutting speed.