service@jtgroup.com.cn
+86-057483005999
+86-18057437999
en
en
Ningbo Jintian Copper (Group) Co., Ltd.
Ningbo Jintian Copper (Group) Co., Ltd.
Code

Designation and Standards

  • Standard Designation: H70 (Common Brass)

  • International/National Standards: GB/T 2059-2000 (Strips), GB/T 5231-2012 (Wrought Brass)

  • Other Standards: JIS H3100 (Japanese Standard), ASTM B36/B36M (American Standard)

  • Material Category: Copper-Zinc Alloy (Cu-Zn), Copper content 68.5%-71.5%, Zinc as the remainder.


Product Features

  • Excellent Plasticity: H70 has the best plasticity among brasses, with excellent cold and hot working ability, suitable for complex stamped parts, such as corrugated pipes, cartridge cases.

  • High Strength: It has a wide tensile strength range (M≥290 MPa, up to 570 MPa(Y)), offering a good balance between strength and ductility.

  • Easy Machinability: Good cutting performance, supports welding, soldering and brazing, but annealing is required after cold working to prevent stress corrosion cracking.

  • Corrosion Resistance: Provides good resistance to freshwater and atmospheric environments but requires careful application in seawater or high-stress conditions.


Common Product Forms and Specifications

Product Form

Specification Range

Delivery Condition

Plate

Thickness 1-150mm (Commonly 4-14mm)

R (Hot Rolled), M (Annealed), Y (Hard)

Strip

Thickness 0.1-3.0mm

M, Y2, Y4, etc.

Tube

Outer Diameter 10-300mm (Capillary Tube 1-6.1mm)

M (Annealed), Y2 (1/2 Hard)

Bar

Diameter 4-350mm

Black Round and Bright Drawn Bars

Wire

Diameter 0.1-12.7mm

Coils or Straight rods


Chemical Composition

Element

Cu

Zn

Pb

Fe

Ni

Total Impurities

Content (%)

68.5-71.5

Remainder

≤0.03

≤0.10

≤0.5 (Depending on Standard)

≤0.3


Physical Properties

Property

Value

Remarks

Density

8.53 g/cm³

Lighter than pure copper, providing a lightweight advantage

Thermal Conductivity

140.2-141.7 W/(m·℃)

Comparable to pure copper, ideal for heat dissipation applications

Melting Point

966-1001℃

Alloy melting range

Coefficient of Thermal Expansion

19.1×10⁻⁶/℃ (20-300℃)

Good thermal stability

Electrical Conductivity

~32% IACS (M)

Lower than pure copper, but sufficient for general conductivity applications


Mechanical Properties

Property

Value

Test Condition

Tensile Strength (σb)

290-570 MPa

Varies significantly depending on condition (M/Y)

Elongation (δ10)

3%-45%

Up to 45% (M)

Hardness (HV)

55-190

Higher hardness (Y)

Annealing Temperature

600-700℃ (Eliminate cold work hardening)

Recommended for conventional furnace annealing

Hot Working Temperature

820-870℃

Prevents zinc volatilization


Core Advantages

  • Outstanding Comprehensive Performance: offers the best plasticity among brasses with balanced strength, making it suitable for deep drawing, bending, and other complex processes.

  • Wide Form Adaptability: Available in plates, tubes, wires, and more, fulfilling various industrial customization needs.

  • Cost-Effectiveness: Lower cost compared to Alpha Brass Alloy, making it ideal for mass production.


Product Applications

  • Electronics and Electricals: Radiator housings, conductive terminals, instrument housings.

  • Industrial Manufacturing: Corrugated pipes, cartridge cases, gaskets, cold-stamped parts.

  • Construction and Marine: Plumbing fittings, condenser tubes (requires corrosion protection in seawater).

  • Paper-Making Equipment: Paper-making pipes, metal mesh screens.


Processing Considerations

  • Annealing Treatment: After cold working, annealing at 600-700℃ is recommended to relieve internal stress and prevent stress corrosion cracking.

  • Welding Process: Argon protected welding is recommended to avoid zinc evaporation and porosity defects.

  • Temperature Control: Hot working temperature should not exceed 870℃ to prevent grain coarsening.


Frequently Asked Questions

Q: What is the difference between H70 and Copper (T2)?

A: H70 is brass (Copper-Zinc Alloy) with higher strength and lower cost; T2 is pure copper (Cu≥99.9%) with superior electrical conductivity but lower strength.


Q: Is H70 suitable for seawater environments?

A: Direct use in seawater is not recommended due to higher corrosion rates (0.0075-0.1 mm/a). Protective coatings or Tin Brass should be used instead.


Q: Why is annealing necessary after cold working H70?

A: Cold work hardening induces internal stress, leading to stress corrosion cracking. Annealing restores plasticity and eliminates stress.


Standard References

  • Chemical Composition and Processing: GB/T 2059-2000, GB/T 5231-2012.

  • Mechanical Property Testing: GB/T 228.1 (Tensile Test).

  • International Standards: ASTM B36 (General Standard for Plates), JIS H3100 (Japanese Standard for Tubes).


Note: The above data is compiled from multiple industrial standards and technical documents. Actual performance may vary depending on production processes and testing conditions. Refer to supplier test reports for specific values.