C18700 Free-Machining Copper

C18700 Free-Machining Copper

290–480 MPa
TENSILE STR
0.8–1.5% Pb
LEAD
ASTM B187
SPEC STD
C18700 free-machining copper is a leaded high-copper alloy with about 1% lead for fast screw-machine output while keeping conductivity near 96% IACS. It is used for connectors, terminals, and switch parts where both machinability and electrical performance matter.
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Product Overview

C18700 is a wrought, lightly alloyed copper grade (EN CuPb1P) formulated for free machining. It carries 98.0–99.2% copper with 0.8–1.5% lead added to break up chips and improve screw-machine productivity, while residual elements stay low. The lead is retained in the structure rather than forming a separate strengthening phase, so the alloy keeps most of copper’s conductivity. It is supplied as rod, bar, and wire to ASTM B187 and ASTM B224.

In the H04 (hard) temper, C18700 reaches about 410–480 MPa tensile strength, 380 MPa typical yield, 8–12% elongation, and Rockwell B 55 hardness, with electrical conductivity around 96% IACS and thermal conductivity near 380 W/m·K. It solders and brazes well, has good cold-work capacity, and carries a machinability rating of about 85 (free-cutting brass = 100), which is high for a copper-grade material. Hot forming is rated poor, so finishing is done by machining rather than forging.

Linsy Copper supplies C18700 free-machining copper as rod, bar, and custom screw-machine stock with low-MOQ production (typical lead time 10–60 days), in-house CNC machining and surface finishing, an MTR/MTC for every order, and optional SGS testing on request. Contact our Shenzhen team for a quotation within one hour.

Key Features

High machinability (~85 rating) for fast screw-machine output
Near-pure-copper conductivity (~96% IACS) for electrical parts
Lead addition breaks chips and improves surface finish
Good solderability and brazeability for assembled contacts
Excellent cold-work capacity for forming and bending
Supplied to ASTM B187 / B224 as rod, bar, and wire

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.

Applications & Use Cases

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

Frequently Asked Questions

Find answers to common questions about our products, services, and ordering process

C18700 adds about 1% lead to copper, trading a small amount of conductivity (roughly 96% IACS instead of ~101%) for a large gain in machinability. Pure copper machines poorly; C18700 runs cleanly on screw machines, which is why it is chosen for high-volume electrical parts.
No. C18700 contains 0.8–1.5% lead for machinability. For lead-free requirements (RoHS, potable-water, or food contact), use a lead-free brass such as C87850 (eco brass) instead.
Conductivity is about 96% IACS, close to pure copper. It is high enough for connectors, terminals, and current-carrying switch parts where both electrical performance and fast machining are required.
ASTM B187 covers rod and bar, and ASTM B224 covers wire. Mechanical values here follow the H04 (hard) temper commonly used for screw-machine stock.
Linsy Copper supplies C18700 as rod, bar, and custom screw-machine stock at low MOQ with a typical lead time of 10–60 days, ships an MTR/MTC with every order, and offers optional SGS testing on request.
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