Copper and zinc are the main components of brass. Copper is nonreactive, although it is damaged and malleable. Zinc is robust yet reactive and more susceptible to corrosion. When copper and zinc are combined, the resulting metal, brass, retains the best qualities of both metals. However, even standard brass can be susceptible to corrosion in the form of dezincification.
Alloy is subjected to certain conditions, such as a specific pH and concentration of chlorides. It also involves applications like high-temperature water, soft water, seawater, or brackish water. In this condition, a chemical reaction eliminates zinc from the alloy. The term dezincification is extreme corrosion.
When dezincification happens, mineral oxides or white powdery substances build up on the exterior of a valve. This can cause the body or stem from leaking. Allowing dezincification to improve can lead to corrosion. It will weaken the metal to the point where gases or liquids can leak. A dezincification-resistant alloy, such as a DZR brass design, is needed to solve this issue. When harsh conditions exist, this material is the best choice.
What is the Dezincification Brass?
Dezincification is a de-alloying process where the selective removal of Zn leaves a relatively porous and weak Cu and Cu oxide layer. Yet, it occurs in DZR brass Cu-Zn alloys containing more than 15% Zn. Similar corrosion occurs under the initial corrosion layer. This can result in the gradual replacement of robust brass with porous copper. If not prevented, this corrosion action will weaken the metal. The liquids or gases can penetrate through the absorbent layer.
Standard extruded brass has a combination of alpha and beta phases. Yet, it involves tiny particles of lead, which make it easy to work with. Zinc dissolves up to 37% copper in binary brasses, demonstrating an alpha phase. As the amount of zinc increases, the beta phase appears.
The fact that alpha is soft at room temperature. On the other side, beta is easy to shape when heat is provided—extruded brass has a wide range of uses and unique properties. But dezincification is especially likely to happen in the beta phase. DZR brass is resistant to dezincification because it has a specific chemical composition. During this process, the dangerous ß-phase changes into a different stage.
Three factors must be considered for the ideal design with the least beta content and the most safety against dezincification.
- Careful control of temperature and time during production. It also involves special heat treatment.
- A slight increase in the amount of copper to reduce the amount of beta phase
- A small amount of arsenic is added, which indicates that the alpha phase is protected.
|Modulus of Elasticity
Main Products Requiring DZR Brass
Due to its anti-corrosion characteristics, the material can create various products. However, one of the most frequent applications of DZR Brass is the production of ball valves. Ball Valves are utilized as shut-off valves. It regulates the flow of corrosive liquids or gases through a rotating ball with a bore. They are used in the natural gas and oil industries, chemical storage, and household applications.
Conditions for Dezincification Brass
Various factors affect the brass to de-zincify. Here are some essential elements;
- Sea or brackish water
- Polluted environment
- The hardness of the water, alkalinity, or acidity of water beyond the PH of 7.
- Corrosive soil like a salt marsh, acid peat
- The greater risk with higher temperature
- Large brass grain size
To ensure that the quality of DZR-produced items is retained and that the brass is rendered anti-corrosive, great care must be taken during manufacturing.
Brass is the most effective material, even though several materials, such as bronze and copper, are resistant to dezincification. This is because brass can be produced in large quantities; yet, brass, composed of Copper and Zinc, is not resistant to dezincification in its particular.
Adding components such as antimony and arsenic enables the fabrication of a copper alloy. It prevents the selective dissolution of zinc produced by water contact. In addition to enhancing the brass’ anti-corrosion qualities, the manufacturing procedure for DZR Brass boosts the metal’s strength.
Dezincification resistance is ensured through strict regulation over each step in the manufacturing process. To avoid the potential of corrosion, fabricators must have control over casting, brass rod manufacture, heat treating, and shaping, among other procedures. Significant control over key alloying components and producers must also eliminate any impurities.
Dezincification tests can be performed periodically on components to ensure that the heat treatment is effective and that the metal’s constitution is correct. The dezincification test requires a 24-hour exposure to a sort of heated cupric chloride solution.
Enhancing the Lifespan
Due to their use with liquids, gases, and corrosive chemicals, it is particularly advantageous for the Ball Valves to be made from DZR Brass. They can be installed without the risk of leakage for a more extended period.
Different manufacturers offer a selection of Ball Valves with ‘Butterfly’ and ‘Lever’ handles made of DZR Brass. This significantly reduces the likelihood of DZR ball valves malfunctioning or leaking. Standard brass alloys are susceptible to zinc leaching. It is also vulnerable to deterioration when exposed to high levels of hostile water. DZR ball valves are ideal for installations where zinc leaching damages the material’s molecular structure.
Overall, the use of DZR Brass in producing products such as Ball Valves extends the lifespan of a system. Yet, it reduces the hazards of leakage (such as pollution). Installers and Specifiers must seek out DZR and WR.
There are numerous varieties of DZR Brass available for incorporation into manufactured goods. DZR Brass must have a zinc level below 15% to prevent dezincification. Yet, adding inhibitors permits the brass to have a more excellent zinc content. DZR Brass is offered in CW6265, CW602N, and CW626N specifications for brass rods with a lower zinc percentage than conventional brass rods.