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

C6870 Brass

Brass

Grade Name

C6870 Aluminum Brass (Corrosion-Resistant Brass)


Key Features

  • Superior Corrosion Resistance: Aluminum (1.8–2.5%) and arsenic (0.02–0.10%) prevent dezincification, ideal for seawater environments.

  • High Strength & Workability: Tensile strength ≥380 MPa (annealed), adaptable to cold/hot working and welding.

  • Thermal Conductivity: 100 W/(m·K), suitable for heat exchangers.

  • Eco-Compliance: RoHS-compliant (Pb ≤0.05%), meets ASTM B111 standards.


Product Forms & Dimensions


Form

Size Range

Standards

Rod

Diameter 5–300mm, Length 1–12m

ASTM B124M

Plate

Thickness 1.0–50mm, Width 200–2000mm

JIS H3300

Tube

OD 10–300mm, Wall Thickness 1.0–30mm

EN 12449:1999

Strip

Thickness 0.2–3.0mm, Width ≤300mm

ASTM B134

Wire

Diameter 0.5–12mm, Coil ≥5kg

DIN 17660



Chemical Composition


Element

Content (%)

Standard Range

Cu

76.0–79.0

Main Component (ASTM B111)

Al

1.8–2.5

Corrosion Resistance

As

0.02–0.10

Dezincification Inhibitor

Zn

Balance

Balancing Component

Pb

≤0.05

RoHS Limit

Fe+Sn

≤0.5

Impurity Control

Impurities

≤0.5

Total Limit



Physical Properties


Property

Value/Description

Density

8.40 g/cm³

Electrical Conductivity

28% IACS (20℃)

Thermal Conductivity

100 W/(m·K)

Thermal Expansion

19.5×10⁻⁶/℃ (20–300℃)



Mechanical Properties


Condition

Tensile Strength (MPa)

Elongation (%)

Hardness (HV)

Annealed (O)

380–450

≥25

80–100 HV

Half-Hard (H02)

450–550

≥15

120–150 HV

Hard (H)

≥550

≥8

≥160 HV


Core Advantages

1. Marine-Grade Durability: 3–5x longer service life in seawater vs. standard brass.

2. Efficient Heat Dissipation: Ideal for high thermal load applications.

3. Processing Flexibility: Compatible with cold rolling, hot forging, and welding.


Applications

  • Marine Engineering: Ship condenser tubes, desalination equipment.

  • Energy Systems: Heat exchangers in power plants.

  • Chemical Industry: Corrosive fluid pipelines, valve liners.

  • Electronics: Heat sinks for high-power devices.


Processing Guidelines

  • Hot Working: 700–750℃, avoid 300–600℃ brittleness zone.

  • Post-Cold Working: Low-temperature annealing (250–350℃) to prevent stress corrosion.

  • Welding: Use TIG/MIG welding, followed by acid cleaning.


FAQs

Q1: Differences between C6870 and C4430?

A: C4430 (tin brass) has lower strength; C6870 offers higher strength and thermal conductivity.


Q2: Suitability for seawater exposure?

A: Yes, but monitor surface condition and limit flow velocity ≤2 m/s.


Standards

  • ASTM B111M: U.S. condenser and heat exchanger tube standard.

  • JIS H3300-2018: Japanese copper alloy tube standard.

  • DIN 17660: European copper alloy composition standard.


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