Leaded Forging Brass — US Standard

C37700

Forging Brass — CuZn39Pb2 / ASTM B283 · B124

The North American standard for hot-pressed brass die forgings — rated 100 for hot forgeability. 58–61% Cu with 1.5–2.5% Pb gives excellent flow in closed dies plus good machinability (~80%) for finishing operations. EN equivalent: CW612N (CuZn39Pb2); legacy BS designation CZ122.

🔥 100 Hot Forgeability
⚙️ ~80% Machinability
📋 ASTM B283 / B124
⚠️ RoHS Ex 6(c)
🌍 ≡ CW612N · CZ122
100
Hot forgeability — the forging benchmark
58–61%
Copper content (ASTM B283)
1.5–2.5%
Lead — machinability for finishing cuts
Ex 6(c)
RoHS — valid to Jun 2027
Chemical Composition

C37700 — ASTM B283 / B124 Limits

Weight %. Balanced for hot die forging: enough β-phase for flow at forging temperature, enough Pb for clean finish machining.

ElementSymbolMin %Max %Typical %
CopperCu58.061.059.5
ZincZnBalance~38.5
LeadPb1.52.52.0
IronFe0.300.10
Copper (Cu)
~59.5%
Zinc (Zn)
~38.5%
Lead (Pb)
~2.0%
Mechanical Properties

Typical for rod (varies by temper)

PropertyConditionValueUnit
Tensile Strengthas forged, typical~360MPa
Yield Strengthas forged, typical~140MPa
Elongationas forged, typical~40%
Hot Forgeabilityvs C37700 = 100100
Machinabilityvs C36000 = 100~80%
Density8.44g/cm³
Melting Rangesolidus–liquidus885–895°C
Typical Applications
  • Hot-pressed die forgings — fitting bodies, flanges, caps, and housings
  • Gas, pneumatic and hydraulic fitting bodies forged then finish-machined
  • Heavy-section components where bar machining would waste material
  • Hose couplings, unions, and large hex bodies
  • Architectural and hardware forgings
Why choose C37700?

The standard alloy for brass hot forgings

  • Hot forgeability rated 100 — C37700 is the reference grade for forging behaviour in copper alloys
  • Pb 1.5–2.5% — forged blanks finish-machine cleanly at roughly 80% of the free-cutting benchmark
  • ASTM B283 / B124 standardised — the default grade on North American drawings for forged fittings
  • Near-net-shape economy — forging puts metal only where the part needs it, cutting swarf loss on heavy sections
  • EN twin: CW612N — European drawings specify CuZn39Pb2 for the same duty
RoHS & Compliance

Compliance Status

RoHS
Exemption 6(c) Required
Pb 1.5–2.5% — within the 4% copper-alloy allowance. Valid to 30 June 2027.
Drinking Water (US)
Not Suitable — Wetted Parts
NSF/ANSI 372 limits weighted Pb to 0.25% in potable systems. Use a lead-free grade instead.
Lead-free forging alternative
CW510L — CuZn42, hot-forgeable without Pb
International Equivalents

C37700 Cross-Reference

StandardDesignation
UNS / ASTM (USA)C37700 — ASTM B283 / B124
EN — equivalentCW612N / CuZn39Pb2
EN — forging cousinCW617N / CuZn40Pb2
BS (UK legacy)CZ122
Trade nameForging Brass
⚠️ C37700 cross-references to CW612N (CuZn39Pb2). In Europe, hot-forged fittings are more often specified in CW617N (CuZn40Pb2) — both forge well; confirm which your drawing requires.
← EN twin
CW612N
CuZn39Pb2 — same composition family
Forging cousin →
CW617N
CuZn40Pb2 — the EU forging workhorse
↑ All alloys
Materials Library
Frequently Asked Questions

C37700 — common questions

What is C37700 brass?

C37700 — forging brass — is the standard North American grade for hot-pressed brass die forgings per ASTM B283 (forgings) and B124 (forging rod). With 58–61% copper and 1.5–2.5% lead, it is rated 100 for hot forgeability and about 80% for machinability, so forged blanks finish-machine cleanly.

What is the EN (CW) equivalent of C37700?

The EN equivalent is CW612N (CuZn39Pb2); the legacy British designation is CZ122. European forged fittings are also commonly made in CW617N (CuZn40Pb2), which forges equally well — confirm which grade your drawing specifies.

When should I choose a forging over a bar-machined part?

Forging pays off on heavy sections, large hex bodies, and asymmetric shapes where bar machining would turn most of the material into swarf. It also gives an unbroken grain flow around the part shape. Thin, long, or high-precision turned geometries usually stay cheaper machined from bar — we advise per drawing at quotation.

Can Brassland supply C37700 forged components?

Yes — hot-forged brass components are supplied made to your drawing (forging through our qualified forging partners, with finish CNC machining and inspection in-house). The exact grade — C37700 or its EN equivalents — and a Type 3.1 mill certificate are confirmed at quotation.

C37700 forged & machined to your drawing

Hot-forged blanks, finish-machined and inspected in Jamnagar. ISO 9001:2015. Quote within 24 hours.

Request a Quote
Sources & References

Verify this datasheet against the primary source

Composition ranges, mechanical properties, machinability ratings and regulatory data on this page are cross-referenced against the publishers below. Tolerances and minimum values are taken from the relevant published standard at the time of writing — for procurement specification, always reference the current published edition.

Copper Development Association
CDA C37700 alloy datasheet — composition & properties
ASTM B283/B283M
Copper and Copper-Alloy Die Forgings (Hot-Pressed)
MatWeb
Independent material property database — by temper
European Copper Institute
Copper Alliance EU — EN alloy designation system
SteelNumber.com
EN material designation cross-reference
CEN / CENELEC
EN 12164, EN 12165, EN 12167 — EN rod standards
EU RoHS Directive 2011/65
Annex III Exemption 6(c) — valid to 30 Jun 2027
ECHA REACH SVHC List
Lead is on the candidate list (Article 33)
NSF/ANSI/CAN 61
Drinking water system components (US/CA)
Brassland — Standards Guide
Plain-English explainer for every standard above

Last reviewed: June 2026. EN/ISO/ASTM standards are updated periodically. This datasheet reflects the editions listed; for safety-critical or contract-critical applications, always verify against the current published edition of the standard. For project-specific deviations or supplier-specific composition windows, request a Type 3.1 mill certificate (EN 10204) with your order.