Posted by RWVC on | Comments Off on How Heat-Treated Brass Achieves Dezincification Resistance
Plumbing and HVAC systems expose brass fittings to municipal water, glycol loops, and years of temperature swings. That exposure creates a real risk: dezincification, a corrosion process that strips zinc from brass and leaves a weak, porous structure behind. Resistance to dezincification comes down to alloy chemistry and heat treatment, confirmed through standardized lab testing. Learn more about the metallurgy behind dezincification, the heat treatment that produces dezincification-resistant brass, and the test that confirms it.
What Is Dezincification, and Why Does It Matter in Plumbing Systems?
Dezincification happens when zinc leaches out of a copper-zinc alloy, leaving behind a soft, copper-rich layer that cracks under pressure. The reaction speeds up under these water conditions:
High chloride content
Low pH
Elevated temperature
Stagnant or low-flow sections of a line
These conditions turn up in municipal supply lines and closed HVAC loops alike. A dezincified valve body can look intact from the outside while its wall thickness drops well below the rated strength. For a design engineer specifying components behind a wall or under a slab, that hidden failure mode can be especially harmful. Choosing dezincification-resistant brass helps prevent the kind of hidden failure that surface inspection alone can’t catch.
The Metallurgy: Alpha vs. Beta Phase in Copper-Zinc Alloys
Standard brass forms two crystal structures within the same alloy: alpha phase and beta phase. Alpha phase carries less zinc and resists corrosion. Beta phase carries more zinc, machines faster, and corrodes faster too. A valve body cut from standard brass often contains scattered beta grains, and each one gives dezincification a foothold.
Dezincification-resistant brass begins with a formulation designed to keep beta-phase content low from the outset. From there, the alloy still needs one more step to reach full resistance to dezincification: heat treatment.
How Heat Treatment Creates a Dezincification-Resistant Structure
Heat treatment converts the alloy’s remaining beta phase into a stable alpha phase. Manufacturers heat the cast or forged brass to a controlled temperature, hold it there for a set period, then cool it under controlled conditions. This step redistributes zinc atoms into one uniform alpha structure instead of the patchy alpha-beta mix found in untreated brass. Alpha grains resist selective zinc leaching, so the finished part carries real resistance to dezincification. Without this step, the valve retains small beta pockets that can corrode from the inside out over time.
Verifying Performance with the ISO 6509 Test
ISO 6509 gives engineers a repeatable way to confirm resistance to dezincification instead of relying solely on a supplier’s word. In a lab, a cross-section of the brass is exposed to a corrosive test solution for a set exposure period, and then the depth of the corroded layer is measured under a microscope against the maximum attack depth the standard allows.
All RWV dezincification-resistant brass valves are tested against this standard by an independent laboratory, so the alloy and the heat treatment are verified to hold up under conditions built to mimic years of field exposure.
Specifying DZR Brass Valves from RED-WHITE VALVE CORP.
At RED-WHITE VALVE CORP. (RWV), we manufacture every brass and bronze valve in our own factories, which keeps alloy sourcing, heat treatment, and quality checks under one roof instead of scattered across supply chain partners. For plumbing and HVAC specifications where potable water or glycol contact is a factor, RWV supplies dezincification-resistant brass valves and ISO 6509 test data to document that resistance—closing off a failure mode that might otherwise surface years after installation.
Resistance to dezincification comes from two steps working together: formulating an alloy with low beta phase content and a heat treatment cycle that locks in a uniform alpha structure, confirmed by ISO 6509 testing. If you’re specifying brass valves for a plumbing or HVAC project and want to talk through alloy grade, heat treatment records, or test data, contact RWV or request a quote to start a conversation.
Posted by RWVC on | Comments Off on Bronze vs. Brass Valves
Bronze and brass have similar compositions, appearances, and applications. They are both widely used copper alloy materials for valves, but they have different properties and price points. We’ll discuss these properties in more detail here, as well as their specific applications and advantages.
Bronze Valves
Bronze valves date back to the Romans during the first century B.C. Today, bronze is still primarily made from copper and tin, but modern additives typically include aluminum or manganese. Some bronze alloys can hold a polish if they contain nickel or lead, but generally bronze has a rough, porous finish.
Bronze valves can only be made by mold casting or machining cast ingots.
Brass Valves
Brass is a copper and zinc alloy. Brass valves are more versatile and malleable than bronze, and they can be made through casting, heat extrusion, forging, or cold drawing. The material naturally has a smooth finish that can save on finishing costs.
Brass is extremely corrosion-resistant, but prolonged exposure to chlorine or water can break down the zinc in the metal. Valves made of brass are ideal for natural gas and potable water applications.
Applications of Bronze Valves vs Brass Valves
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Because of their specific properties, bronze valves are best suited for the following applications and industries:
Petrochemical
Marine
Safety relief
Flow direction control
Flow shut-off
Flow Control
Brass valves are uniquely suited to these applications:
Air and liquid shut-off
Natural gas shut-off
Flow direction control
Potable water
Flow Control
Advantages of DZR Brass vs. Yellow Brass Valves
DZR brass, or dezincification-resistant brass, refers to brass with particular elements that resist the removal of zinc by water. With non-DZR brass, continuous water flow could leave behind a weak and porous copper structure. DZR brass is ideal for pipes, fittings, and valves for potable water, or high-pressure water situations, such as waterworks.
DZR brass is formulated through a heat treatment process to resist dezincification and increase strength. In contrast, ordinary yellow brass water valves can corrode quickly. They are generally cheaper and easier to machine.. DZR brass valves are superior because of their higher copper content and lower lead and zinc content. The longevity benefits of DZR brass far outweigh any financial savings from using yellow brass valves.
Valves from RED-WHITE VALVE CORP.
With these properties of brass and bronze valves in mind, you can make a more informed decision for your valve application. RED-WHITE VALVE CORP. has provided top-notch service to the plumbing, commercial, HVAC, and industrial markets since 1971. We offer a vast selection of products, including standard valves and lead-free valves. Contact us for information or to start your project.
Posted by RWVC on | Comments Off on Advantages of DZR Brass Valves
Dezincification-resistant (DZR) brass can help prevent corrosion from negatively affecting various components, including valves used in a number of applications. Although many applications use valves and other fittings made from normal brass alloys, certain impurities could cause a type of corrosion known as dezincification. In applications where dezincification is a risk, DZR brass valves provide enhanced protection to maximize the longevity of certain components.
Here we’ll review what dezincification specifically is and how DZR brass valves and other parts can protect against it.
What Is Dezincification?
Brass is a combination of mostly copper and zinc. While copper is un-reactive, it is vulnerable to damage and extremely malleable. Zinc, on the other hand, is strong but reactive and more easily corroded. When the two metals combine to form brass, the resulting metal is ideally both strong and un-reactive, featuring the favorable properties of copper and zinc. However, normal brass is potentially still vulnerable to corrosion in the form of dezincification.
Dezincification entails the loss of zinc through corrosion because of its reactiveness. It’s a certain type of corrosion process resulting from water contact. In turn, water removes zinc from the copper alloy, forming a copper-rich and porous metal with compromised mechanical strength. Specifically, the removal of zinc leaves a layer of Cu and Cu oxide. Over time, further corrosion can continue underneath this layer, gradually leaving weaker copper in place of more durable brass. An in-service valve suffering from dezincification can have a white powdery substance or mineral stains on its exterior surface.
If dezincification is allowed to continue, the corrosion will eventually weaken the metal and enable gases or liquids to seep through it.
What Is DZR Brass?
Dezincification-resistant (DZR) brass helps prevent dezincification of brass materials, increasing their lifespan and enabling various applications to benefit from consistent durability. Many parts feature DZR brass construction, including fittings and valves in potable water and other types of environments with corrosive water.
DZR brass’s composition features superior strength that makes it suitable for a wider range of applications in need of a reliable metal product.
Generally, DZR brass includes higher copper content along with lower zinc content. NSF lead free* DZR alloys are also available. Additionally, other trace elements compose this metal. A unique heat treatment process further enhances the properties of DZR brass.
Quality Assurance
Strict control over every stage of the manufacturing process helps assure dezincification resistance. It’s important for fabricators to have control over casting, brass rod production, heat treating, and shaping, along with other processes, to eliminate the possibility of corrosion. It’s equally crucial to have total control over major alloying elements, and manufacturers must also exclude any unwanted impurities.
Following heat treatment, dezincification tests can perform periodic checks on components, which helps make sure that the heat treatment was successful and that the metal features the correct composition. The closely controlled dezincification test involves 24-hour exposure to a type of hot cupric chloride solution. At RED-WHITE VALVE CORP., our products undergo the ISO 6957:1988 (Copper alloys – Ammonia test for stress corrosion resistance) test. This uses a test solution with a pH of 9.5. Following exposure, the test applies slight deformation to samples prior to inspection, which reveals fine cracks and other faults.
Reliable DZR Brass Products from RED-WHITE VALVE CORP.
DZR brass valves and other products can increase the strength of systems exposed to highly corrosive water, eliminating the need for frequent maintenance and the replacement of parts. RED-WHITE VALVE CORP. offers a wide selection of DZR brass products to meet the needs of a diverse range of applications.
For more information about our products and assistance with finding the right product for your application, contact us today.
