Learn About Brass Stamping

Characteristic and advantages of brass

Brass is a copper-zinc alloy. Brass composed of copper and zinc is called ordinary brass.

Material advantages:

It has high strength, high hardness, and strong chemical resistance. The mechanical properties of cutting are also outstanding.

Brass has strong wear resistance. Special brass is also called special brass. It has high strength, high hardness, and strong chemical resistance. The mechanical properties of cutting are also outstanding. Seamless copper tube drawn from brass is soft and wear-resistant.

 

What type do brass stampings use

Brass stamping parts are usually brass because of their conductivity, heat conductivity, corrosion resistance, low resistance, and easy welding and conduction.

[Common models for brass stamping] Common models for stamping are H62, H65, H68, etc.

1.H65: The property is between H68 and H62, and the price is lower than H68. It has good mechanical properties, high strength, and plasticity, can withstand cold and hot pressure processing and is prone to corrosion cracking. H65 brass is used for making hardware, daily necessities, screws, and other products.

2.H62: Ordinary brass with good mechanical properties, good plasticity in hot state and unconscious state, good machinability, easy to braze and weld, corrosion resistance, but prone to corrosion cracking. In addition, the price is low, and it is a common brass variety widely used. It can be used for various stressed parts made by deep drawing and bending, such as pins, rivets, washers, nuts, conduits, barometer springs, screens, radiator parts, etc.

3.H68: Very good plasticity and high strength, good machinability, easy welding, very stable to general corrosion, but prone to corrosion cracking. It is one of the most widely used varieties of ordinary brass. The property of H68 brass is very similar to that of H70, but there is a tendency of “seasonal cracking” during cold working. It is used for complex cold stamping and deep stamping parts, such as bellows, cartridge shells, etc.

Passivation Treatment Method for Anti-oxidation and Anti discoloration of Brass after Stamping

Anti-oxidation and passivation treatment of copper is a necessary process in the copper processing process. The lack of such treatment will lead to various adverse conditions, such as oxidation, discoloration, and blackening of copper parts, which will seriously affect the product quality.

Suppose the brass parts are not treated with copper passivation and oxidation resistance after stamping, degreasing, and cleaning. In that case, it is very easy to appear oxidation discoloration, blackening, and other undesirable phenomena, and even lead product scrapping.

Therefore, in the brass stamping process, the copper oxidation protection process has become very important in the processing link. To ensure product quality, it is necessary to conduct the copper oxidation protection passivation treatment.

Here are the specific solutions:

The first step is the pretreatment of brass passivation – degreasing: before the passivation and oxidation prevention treatment, the surface of copper parts must be clean and free of oil contamination and oxides. Otherwise, the passivation protective film will be incomplete, and the corresponding protection effect will not be achieved; After stamping, the surface of copper has processing residues, such as stamping oil, fingerprints, dust, and a small number of oxides. This requires an oil removal process to remove the residual stains on the surface. Generally, using a copper bright cleaning agent can remove oil and oxides; If the oil stain is serious, the alkaline degreaser shall be used for degreasing treatment before the bright cleaner treatment.

 

If there are special requirements, corresponding treatment processes are also required, such as increasing brightness for chemical polishing, deburring for vibration grinding, defect removal for wire drawing effect, wire drawing treatment, etc.

 

The second step is brass passivation and oxidation resistance treatment: generally, an environment-friendly chromium-free passivation solution is used for oxidation resistance treatment. This step is very critical. The product’s oxidation resistance quality depends on the compactness and integrity of the passivation film, so it is critical to select the correct passivation agent. The passivation treatment process is very simple. The passivation treatment effect can be achieved by putting the product with surface pretreatment into the passivation solution and fully contacting the passivation solution for more than 5 minutes. Generally, the passivation solution is a weak alkaline liquid, so it is necessary to prevent acidic liquid from entering the passivation solution, which will lead to the failure of the passivation solution.

 

The third step is water washing and drying: washing must be carried out between each step to prevent the previous liquid medicine from polluting the liquid medicine for subsequent treatment, resulting in poor surface treatment. The drying temperature should be well controlled, generally at 80~100 ℃. It should not be baked at too high a temperature to prevent the passivation film from being damaged due to high temperature.