What Is the Difference Between CW617N and CW602N Brass?

Short answer: CW617N (CuZn40Pb2) is a leaded, two-phase forging brass chosen for easy hot forging and machining. CW602N (CuZn36Pb2As) has less zinc and an arsenic addition so that, after the correct heat treatment, it resists dezincification in aggressive water. Both carry roughly 2% lead, so neither one is a lead-free grade. Choose CW602N when water chemistry or the destination market calls for dezincification resistance.

Key Takeaways

• The EN designation spells out the nominal recipe: CuZn40Pb2 is about 40% zinc and 2% lead; CuZn36Pb2As is about 36% zinc and 2% lead with arsenic added.
• Dezincification resistance is a tested property of the finished part, not a label on the bar, so it is verified to ISO 6509-1 after forging and heat treatment.
• Dezincification resistance and lead-free status are separate questions; CW602N answers the first, not the second.
• US “lead free” means a weighted average of 0.25% lead across wetted surfaces, and the EU lead limit at the tap tightens from 10 µg/l to 5 µg/l by 12 January 2036.
• Write the grade, the test requirement and the destination market on the RFQ, because each one changes the quotation.

What is the difference between CW617N and CW602N?

The difference is dezincification resistance: CW602N is formulated and heat treated to resist it, while CW617N is not. Both are leaded brasses from the European EN designation system, and both forge and machine well. CW617N is the general-purpose workhorse for hot-forged fittings and inserts. CW602N trades a little of that ease for a more corrosion-tolerant structure.

The two grades are often confused because they share a lead level and similar applications. In practice they behave differently only when water attacks the zinc in the alloy. That condition is common enough in some regions that buyers there specify CW602N by default.

What do the EN designations tell you?

The EN designation tells you the alloy’s nominal chemistry, while the CW number is simply its catalog code. European copper alloys carry two names that point to the same material:

• Material number (CW617N, CW602N): A code in which “C” means copper-based, “W” means wrought, and the final letter groups the alloy family. The digits identify the grade and carry no chemistry.
• Symbolic designation (CuZn40Pb2, CuZn36Pb2As): A recipe written out. Copper is the balance, and each element is followed by its nominal percentage, so CuZn36Pb2As reads as copper with about 36% zinc, about 2% lead and a small arsenic addition.
• Product standard: The exact composition limits, mechanical properties and tolerances sit in the product standard for the form you buy. Forging stock falls under EN 12165, current in its 2024 edition, which specifies composition, property requirements and dimensional tolerances for copper alloy forging stock.
• National equivalents: Suppliers often quote local names, such as HPb59-1 in China for a grade comparable to CW617N. Treat these as approximate matches and ask for the chemistry on the mill certificate.

Use the symbolic name when you need to explain a grade to a non-specialist, and the CW number on drawings and purchase orders. Quote the product standard alongside it, because the same grade can be supplied as forging stock, rod or tube under different standards.

Why does dezincification matter for a brass insert?

Dezincification matters because it turns sound brass into weak, porous copper without changing the part’s outline. Water leaches zinc out of the alloy, starting with the zinc-rich beta phase in two-phase brasses like CW617N. The insert can look intact while its threads and sealing faces lose strength underneath.

Inserts are particularly exposed because the metal sits permanently in the waterway of a plastic fitting. The conditions that push buyers toward a dezincification-resistant grade include:

• Aggressive water chemistry: Soft water and water with high chloride relative to hardness are commonly linked to dezincification. Local utilities and building codes in affected regions often set the requirement.
• Hot water service: Higher temperature speeds up the corrosion reaction, so hot lines and heating circuits deserve more caution than cold-only lines.
• Long design life: A molded-in insert cannot be replaced without replacing the fitting, so slow damage still ends in a failed product.
• Specification by market: Some importers and project specifiers write DZR brass into every tender for their region, regardless of local water data.

Corrosion is one of several ways an insert can fail in service. Our guide to brass insert failure modes, from pull-out to leakage and corrosion covers the mechanical failures that grade selection does not solve.

How is dezincification resistance tested?

Dezincification resistance is tested to ISO 6509-1, which measures how deep zinc loss penetrates a sample after a standard exposure. The standard specifies a method for copper alloys with zinc exposed to fresh, saline or drinking water, and it is intended for alloys with more than 15% zinc by mass, which covers both grades. Assessment criteria sit in a separate part, ISO 6509-2, so a test report should state which acceptance limit was applied.

The test has to be run on parts made the way production parts are made. Arsenic alone does not make CW602N resistant; the heat treatment after forging is what develops the protective structure. A sound verification sequence looks like this:

1. Confirm the grade: Check the mill certificate chemistry against the specified grade for every heat or lot of bar.
2. Confirm the process: Ask the supplier to state the heat treatment applied after forging and keep it fixed once samples are approved.
3. Test finished parts: Section a sample from forged and heat-treated inserts, not from the raw bar, and test to ISO 6509-1.
4. State the criterion: Record the acceptance limit used, whether from ISO 6509-2 or from the standard your market applies.
5. Repeat on change: Retest when the bar source, the forging die or the heat treatment changes.

A certificate that says “DZR brass” with no test report attached tells you only what was ordered, not what was delivered. Ask for the report tied to the part number and production lot.

Is CW617N or CW602N lead-free?

No, neither CW617N nor CW602N is a lead-free grade; both contain about 2% lead by design. Lead improves machinability, which is why both grades cut cleanly on CNC equipment. Lead content is regulated separately from dezincification, and the two markets most buyers ship to define it differently:

• United States: The Safe Drinking Water Act defines “lead free” as a weighted average of 0.25% lead across the wetted surfaces of pipes, fittings and fixtures. Since September 1, 2023, manufacturers and importers must certify that regulated products meet the rule. The average is calculated for the whole product, but a 2% lead alloy on its own sits far above the threshold.
• European Union: Directive (EU) 2020/2184 sets the lead parameter at the tap. Its annex states that the 5 µg/l value must be met by 12 January 2036, with 10 µg/l applying until then. Materials in contact with drinking water are covered by Article 11, which the Commission describes as a “one standard – one test – one market” framework, with EU hygiene requirements for these materials applying from December 2026.
• Positive lists: In Europe, acceptable metallic compositions are set by positive lists. Germany’s Federal Environment Agency publishes evaluation criteria with a positive list of metallic materials suitable for drinking water, most recently amended on 9 July 2026, with that amendment binding from 25 July 2028. Check the current list for any grade before you commit to it.

If your market needs low-lead brass, CW602N is not the answer, and a different grade family has to be discussed. Our explainer on NSF/ANSI 61 vs NSF/ANSI 372 for lead-free brass covers how US certification separates lead content from contaminant leaching.

Which grade should you specify for a brass insert?

Specify CW617N for general-purpose inserts and CW602N where the water or the market requires dezincification resistance. The decision usually comes down to four questions:

• Where will the fitting be installed? If the destination region has known dezincification problems or a DZR requirement, CW602N is the safer default.
• Does the insert carry potable hot water? Hot potable service is where corrosion risk and regulatory scrutiny meet, so it justifies the extra verification step.
• Is lead content regulated in the target market? If yes, neither grade solves it alone, and the grade discussion has to move to low-lead alloys.
• Can the supply chain prove the property? Choosing CW602N only makes sense if the supplier controls the heat treatment and provides ISO 6509-1 reports on finished parts.

Grade choice does not change the insert geometry, but it does interact with the forming route. Our comparison of hot forged and machined-from-bar brass inserts explains why forging suits both grades for most insert shapes. For the full insert range and the plastics they suit, see our brass insert fittings page.

What to specify when sourcing CW617N or CW602N inserts

Put the grade, the product standard, the test requirement and the destination market on the RFQ, because each one changes cost and lead time. Buyers who write only “brass” or “DZR brass” usually receive quotes that cannot be compared. The checklist below covers what molders, importers and OEM brands should confirm before sampling:

Settle the grade before tooling, not after the first shipment. A grade change later means new samples, new tests and new paperwork. Molders who supply several markets often keep one drawing and release two grade variants, each with its own part number. Our page for pipe and fitting manufacturers explains how we work with molders on insert specifications.

How does Fenilo approach brass grade on insert orders?

Fenilo’s standard brass for inserts and valve parts is hot-forged CW617N, also known as HPb59-1. Hot forging avoids the defects commonly found in cast parts. Other material grades, including dezincification-resistant or low-lead brass, can be discussed per project once the destination market and test requirements are clear.

Every step happens in one plant in Yuhuan, Zhejiang, so material records stay traceable from bar to finished insert. The process runs from brass bar through:

• Hot forging: Bar is forged close to the final shape.
• Shot blasting: Forged blanks are cleaned before machining.
• CNC machining: Threads, bores and knurls are cut, with the knurl pattern and size customizable to the customer’s molding process.
• Inspection and packing: Parts pass five quality-control stages: incoming inspection of all brass material, in-process dimensional checks, pressure and leak testing for valve products, finished-product inspection, and continuous improvement based on production data and customer feedback.

Samples are available for assembly testing and quality evaluation, which is the stage to run your own molding trials. The same forged brass goes into finished valves; see our PPR ball valve range for how it is used beyond inserts.

FAQ

Bottom line: CW617N is the standard leaded forging brass, and CW602N is its dezincification-resistant counterpart, proven only by heat treatment and ISO 6509-1 testing on finished parts. Neither grade is lead-free. Write the grade, the test requirement and the destination market on your RFQ, and settle the choice before tooling.