C3771 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

C3771 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 of C3771 Material

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.