C31400 Leaded Commercial Bronze

C31400 Leaded Commercial Bronze

42% IACS
CONDUCTIVITY
80 / 100
MACHINABILITY
ASTM B140
SPEC STANDARD
C31400 leaded commercial bronze is a free-machining copper-zinc alloy with 1.3–2.5% lead and 42% IACS conductivity, used for screw-machine parts, electrical connectors, and builders hardware. Supplied to ASTM B140.
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Product Overview

C31400 Leaded Commercial Bronze is a free-machining copper-zinc alloy with 1.3–2.5% lead added for chip breakage and faster cutting, covered by ASTM B140 for plate, sheet, strip, and bar. It keeps high electrical conductivity (42% IACS) and good corrosion resistance, placing it between commercial bronze and free-cutting brass in machinability.

With a machinability rating of 80 (free-cutting brass = 100), C31400 is built for screw-machine parts, nuts, screws, door hardware, and wire/cable connectors where repeated turning and threading dominate. It solders and brazes well and cold-works readily, but gas and arc welding are not recommended, so fabricators usually join it by brazing or mechanical assembly. Tempers run H02 (half hard) to H04 (hard).

Linsy Copper supplies C31400 leaded commercial bronze bar, rod, and strip to ASTM B140, with low-MOQ custom sizes for non-stock requirements (typical lead time 10–60 days). Every order ships with an MTR/MTC covering grade, chemistry, and mechanical results, and optional SGS testing is available on request. In-house CNC machining and surface finishing let buyers move from raw stock to finished turned and plated components.

Key Features

Free-machining with 1.3–2.5% lead (machinability rating 80)
High electrical conductivity of 42% IACS
Good corrosion resistance for industrial and architectural use
Excellent solderability and good brazability
Readily cold-worked into screw-machine and turned parts
Supplied to ASTM B140 in bar, rod, and strip forms

Available Sizes

Copper Shape Thickness (mm) Width/Diameter (mm) Length (m)
Bar - Φ5-200 1-6
Wire - Φ0.05-10 Customize
Sheet 0.25-6 500-2500 1-6
Plate 6-200 200-3000 1-6
Strip 0.15-6 8-610 Customize
Tube OD: φ2-600; WT:φ0.2-100mm - 1-6
Coil 0.15-6 3-1250 1-6
Foil < 0.15 10-1350 Customize
Profile Customized Customize Customize

* Custom sizes available upon request. Contact our sales team for special requirements.

Technical Specifications

Precision data for engineering decisions. All values tested per ASTM standards.

01 Chemical Composition

Element Min % Max % Notes
Cu 87.50 90.50 Primary
Pb 1.30 2.50 Free-machining
Zn — Rem. Balance
Fe — 0.10 Trace
Ni — 0.70 Trace
Others — 0.40 Trace

02 Mechanical Properties

Property Half-Hard (H02) Hard (H04)
Tensile Strength (MPa) 345 365
Yield Strength (MPa) 205 275
Elongation % 7 6
Hardness (HRB) 61 65

Applications & Use Cases

Proven solutions across diverse industries. From aerospace to marine environments.

Frequently Asked Questions

Common questions about C31400 leaded commercial bronze specifications, machinability, joining, and supply.

It is used where free machining matters: screw-machine products, nuts, screws, wire and cable connectors, door hardware, and industrial fittings such as pickling crates and racks. The lead addition makes high-volume turning and threading fast and clean.
The primary specification is ASTM B140 / B140M for plate, sheet, strip, and bar. It is also cross-listed as SAE J461/J463 and MIL-V-18436. Linsy Copper matches the applicable ASTM form to the customer's drawing and requirement.
C31400 carries a machinability rating of 80 on the scale where free-cutting brass C36000 equals 100. The 1.3–2.5% lead promotes short chip breakage, so it cuts faster and tools last longer than lead-free commercial bronze.
Soldering is excellent and brazing is good, and it cold-works readily. Gas-shielded arc and coated-metal-arc welding are not recommended because of the lead content, so parts are usually joined by brazing, soldering, or mechanical assembly rather than fusion welding.
C31400 conducts at 42% IACS, high for a leaded alloy. Linsy Copper supplies it to ASTM B140 with low-MOQ custom sizes (lead time typically 10–60 days), an MTR/MTC per order, and optional SGS testing on request.
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