Common Metal Surface Treatments

The concept of metal surface treatment

It refers to the process of changing the surface state and characteristics of a part and optimizing its combination with the matrix material to meet predetermined performance requirements by using cutting-edge new technologies in modern physics, chemistry, metallurgy, and heat treatment disciplines.

1. Metal Surface Modification

Contains the following methods: surface hardening, sandblasting, knurling, wire drawing, polishing, laser surface hardening

（1）metal surface hardening

It is a heat treatment method that austenitizes the surface layer and rapidly cools to harden the surface without changing the chemical composition of the steel.

（2）sandblasted metal surface

The workpiece surface is affected by high-velocity sand and iron particles, which can be used to improve the mechanical properties of the part and change the surface state. This operation can effectively improve mechanical strength, wear-resistance and eliminate residual stress.

（3）metal surface rolling

It is to press the surface of the workpiece with a hard roller at room temperature so that the surface of the workpiece can be hardened by plastic deformation so as to obtain an accurate and smooth surface.

（4）brushed metal surface

Under an external force, the metal is forced through the die. The cross-section of the metal is compressed to change its shape and size. This method is called wire drawing. According to decorative requirements, wire drawing can be made into a variety of threads, such as straight, crimped, wavy, and threaded.

（5）metal surface polishing

Polishing is a finishing method for modifying the surface of a part. It can only obtain a smooth surface without improving the machining accuracy. The Ra value of the polished surface can reach 1.6-0.008 um.

（6）Laser strengthening of metal surfaces

A focused laser beam is used to heat the workpiece rapidly and then rapidly cool the workpiece to obtain a hardened and strengthened surface. Laser surface strengthening has the advantages of small deformation, easy operation, and local strengthening.

2. Metal Surface Alloying Technology

By physical means, additive materials are added to the matrix to form the alloy layer. Common carburizing and nitriding belong to this technique. It puts the metal and the infiltrating agent in the same sealed chamber, activates the metal surface by vacuum heating, and makes carbon and nitrogen enter the metal matrix in the form of atoms so as to achieve the purpose of alloying.

（1）blackening: A black or blue oxide film is produced to isolate the air from corrosion of the workpiece.

（2）phosphating: An electrochemical metal surface treatment method used to protect base metals by depositing clean, water-insoluble phosphates on the surface of workpieces immersed in a phosphating solution.

None of them affect the internal structure of the workpiece. The difference is that blackening steel makes the workpiece shiny, while phosphating adds thickness and dulls the surface of the workpiece. Phosphating is more protective than blackening. In terms of price, blackening is usually more expensive than phosphating.

（3）metal surface coating technology

A coating or coating is formed on the surface of a substrate by physicochemical methods. It is widely used in carbide cutting tools.

TiN coating and TiCN coating on the metal surface

A few microns thick Tin On cutting tools that cut softer copper or mild steel, the material is usually golden. 

Black titanium nitride coatings are usually used where the friction coefficient is small but the hardness is required.

The above is our brief introduction to metal surface treatment. If you are interested in tungsten carbide products and want more information and details, you can CONTACT US by phone or mail at the left, or SEND US MAIL at the bottom of the page.