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Ningbo Jintian Copper (Group) Co., Ltd.
Ningbo Jintian Copper (Group) Co., Ltd.
Code
Brass

C3771 Brass

Brass

Grade Name

C3771 Lead Brass (High-Strength Free-Cutting Brass)


Key Features

  • Superior Machinability: Lead particles reduce tool wear, ideal for CNC and high-speed machining.

  • High Strength & Ductility: Tensile strength ≥350 MPa (annealed), up to ≥600 MPa (hard state).

  • Corrosion Resistance: Stable in dry and freshwater environments; avoid acidic/high humidity.

  • Eco-Compliance: Pb content 1.5–2.5% (RoHS exemption), suitable for precision components.


Product Forms & Dimensions

Form

Size Range

Standards

Rod

Diameter 3–300mm, Length 1–12m

JIS H3250-2015

Plate

Thickness 0.5–60mm, Width 100–2000mm

ASTM B36/B36M

Wire

Diameter 0.3–12mm, Coil ≥5kg

JIS H3300-2018

Tube

OD 6–300mm, Wall Thickness 0.5–30mm

EN 12449:1999

Strip

Thickness 0.1–2.0mm, Width ≤300mm

ASTM B134


Chemical Composition

Element

Content (%)

Standard Range

Cu

58.0–62.0

Main Component (JIS H3250)

Zn

Balance

Balance

Pb

1.5–2.5

RoHS Exemption

Fe+Sn

≤0.5

DIN 17660

Impurities

≤0.75

ASTM B36


Physical Properties

Property

Value/Description

Density

8.75 g/cm³

Electrical Conductivity

24% IACS (20℃)

Thermal Conductivity

110 W/(m·K)

Thermal Expansion

20.5×10⁻⁶/℃ (20–300℃)


Mechanical Properties

Condition

Tensile Strength (MPa)

Elongation (%)

Hardness (HRB/HV)

Annealed (O)

350–450

≥20

55–70 HRB

Half-Hard (H02)

450–550

≥15

75–85 HRB

Hard (H)

≥600

≤8

≥90 HRB


Core Advantages

1. Cost-Effective Machining: Reduced tool wear for mass production.

2. Strength-Ductility Balance: High load capacity with cold-forming adaptability.

3. Surface Versatility: Compatible with electroplating and passivation.


Applications

  • Automotive: Engine valves, transmission gears.

  • Electronics: Precision connectors, heat sinks.

  • Machinery: Bearing cages, wear-resistant bushings.

  • Architecture: High-strength fasteners, decorative hardware.


Processing Guidelines

  • Optimized Cutting: Speed 60–120 m/min; avoid 200–600℃ brittleness zone.

  • Annealing: 650–750℃ for 1–2 hours to relieve stress.

  • Surface Protection: Apply tin plating or electroless nickel for humid environments.


FAQs

Q1: Key differences between C3771 and C3600?

A: C3600 has higher Pb (2–3.7%) for better machinability but lower strength; C3771 balances strength and lead content.


Q2: Is C3771 food-contact safe?

A: Requires FDA/EU 10/2011 compliance; recommend lead-free alternatives (e.g., C4640).


Standards

  • JIS H3250-2015: Copper and copper alloy rods.

  • ASTM B36/B36M: Brass plate and strip standards.

  • EN 12449:1999: Seamless copper tubes.


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