Brass C270

Brass C270 is a versatile, free-machining copper alloy commonly used in various industrial applications such as plumbing, electrical, and automotive systems.

Introduction to Brass C270

Brass C270, also known as commercial brass, is an alloy primarily composed of copper (around 70-80%) and zinc (around 20-30%), with small amounts of iron and lead. Known for its excellent corrosion resistance and good mechanical properties, Brass C270 is a highly versatile material used in CNC machining services. It perfectly balances strength and formability, making it ideal for a wide range of industrial applications. Brass C270 is widely used to manufacture components that require durability, high precision, and high-quality finishes.

This alloy’s good machinability, strength, and corrosion resistance make Brass C270 perfect for creating parts used in electrical, automotive, and plumbing industries. CNC machined Brass C270 parts are often found in electrical connectors, valves, and fittings that require both aesthetic appeal and long-lasting durability.

Chemical, Physical, and Mechanical Properties of Brass C270

Chemical Composition (Typical)

Element	Composition Range (wt.%)	Key Role
Copper (Cu)	60.0–70.0%	Provides strength, corrosion resistance, and conductivity
Zinc (Zn)	30.0–40.0%	Enhances strength and increases material hardness
Iron (Fe)	≤0.5%	Residual element that minimally impacts properties
Lead (Pb)	≤0.1%	Improves machinability and lubricity

Physical Properties

Property	Value (Typical)	Test Standard/Condition
Density	8.4 g/cm³	ASTM B311
Melting Point	900–950°C	ASTM E29
Thermal Conductivity	120 W/m·K at 20°C	ASTM E1952
Electrical Conductivity	20% IACS at 20°C	ASTM B193
Coefficient of Expansion	19 µm/m·°C	ASTM E228
Specific Heat Capacity	380 J/kg·K	ASTM E1269
Elastic Modulus	105 GPa	ASTM E111

Mechanical Properties (Annealed Temper)

Property	Value (Typical)	Test Standard
Tensile Strength	330–400 MPa	ASTM E8/E8M
Yield Strength (0.2%)	220–320 MPa	ASTM E8/E8M
Elongation	35–45%	ASTM E8/E8M
Hardness	60–80 HB	ASTM E10
Fatigue Strength	~200 MPa	ASTM E466
Impact Resistance	Good	ASTM E23

Note: These values are typical for annealed Brass C270 and can vary based on specific processing conditions.

Key Characteristics of Brass C270

Excellent Machinability

Brass C270 is a free-machining alloy, meaning it can be easily cut, drilled, and shaped, making it ideal for high-speed CNC machining operations. It reduces tool wear and minimizes downtime during production.

Moderate Strength and High Ductility

Brass C270 offers a good combination of strength and ductility, making it suitable for parts that need to be formed, bent, or stamped without cracking or breaking.

Corrosion Resistance

Brass C270 has good corrosion resistance, especially in atmospheric and freshwater environments. However, it is not as resistant to seawater as some other alloys, making it more suitable for indoor applications or mild conditions.

Good Electrical and Thermal Conductivity

With a high copper content, Brass C270 offers excellent electrical and thermal conductivity, making it suitable for electrical connectors, terminals, and other components exposed to heat and current.

Aesthetic Appeal

Brass C270 has a rich golden color and a bright, shiny finish that makes it ideal for applications where the appearance of the part is important, such as decorative trims, jewelry, and fixtures.

CNC Machining Challenges and Solutions for Brass C270

Machining Challenges

Chip Formation

Brass C270 produces long, stringy chips when machined at high speeds, which can obstruct the process and decrease productivity.

Solution: Use chip breakers to control chip formation, adjust feed rates, and use air or coolant for chip removal to prevent buildup.

Tool Wear

Although Brass C270 is a free-machining alloy, the cutting forces involved in machining still cause some tool wear over time.

Solution: Use high-performance carbide or ceramic cutting tools to increase tool life and reduce wear during machining.

Surface Finish Quality

Achieving a fine surface finish can be difficult due to the alloy’s tendency to form rough edges during high-speed cutting.

Solution: Use high-speed cutting techniques with sharp, high-quality tools, and apply sufficient lubrication to ensure smooth finishes.

Work Hardening

Brass C270 may experience work hardening if too much pressure or speed is applied during machining.

Solution: Apply moderate cutting speeds, ensure sharp tools, and use adequate coolant to reduce the likelihood of work hardening.

Optimized Machining Strategies

Tool Selection

Parameter	Recommendation	Rationale
Tool Material	Carbide or ceramic tools	Carbide and ceramic tools offer high wear resistance and better cutting performance
Geometry	Positive rake, sharp edges	Improves chip flow and surface finish
Cutting Speed	150–250 m/min	Reduces heat generation and prevents material deformation
Feed Rate	0.10–0.20 mm/rev	Ensures smooth cutting and prevents burr formation
Coolant	Flood coolant or air blast	Reduces heat and enhances surface finish

Brass C270 Cutting Parameters (ISO 513 Compliance)

Operation	Speed (m/min)	Feed (mm/rev)	Depth of Cut (mm)	Coolant Pressure (bar)
Roughing	150–200	0.15–0.20	2.0–3.5	25–35
Finishing	200–250	0.05–0.10	0.5–1.0	30–50

Typical Machining Methods for Brass C270

Machining Process	Function and Benefit for Brass C270
CNC Machining	Ideal for high-speed, precision machining of small components such as connectors and fasteners.
CNC Milling	Ideal for creating slots, grooves, and complex shapes in components like valves and fittings.
CNC Turning	Used for turning cylindrical parts like bushings, gears, and mechanical components.
CNC Drilling	Ideal for precise hole creation for fasteners and mechanical parts.
CNC Boring	Ensures precise internal machining of parts like bearings and bushings.
CNC Grinding	Provides smooth finishes for parts exposed to wear and tear, like gears and shafts.
Multi-Axis Machining	Ideal for producing complex, multi-featured parts for industries such as aerospace and automotive.
Precision Machining	Provides ultra-tight tolerances for components requiring high-precision performance.
EDM Machining	Used for creating intricate features and fine details in automotive and industrial parts.

Surface Treatment for Brass C270 CNC Parts

Electroplating: Enhances corrosion resistance and provides a shiny finish for components like connectors and fittings.
Polishing: Achieves a high-gloss finish that improves both the appearance and functionality of decorative parts.
Brushing: Creates a satin or matte finish for parts exposed to frequent handling or environmental stress.
PVD Coating: Adds a durable coating that increases wear resistance and enhances the part’s life.
Passivation: Enhances the alloy’s corrosion resistance, especially in aggressive environments like chemicals.
Powder Coating: Provides a thick, protective finish ideal for parts exposed to UV light and harsh conditions.
Teflon Coating: Adds non-stick, chemical-resistant properties, ideal for high-performance mechanical applications.
Chrome Plating: Provides a glossy, durable coating that resists corrosion and adds an aesthetic touch to mechanical components.

Industry Applications of Brass C270

Aerospace Industry: Used for manufacturing connectors, bushings, and other parts subjected to high stresses.
Electrical & Power: Ideal for electrical terminals, connectors, and components that require high conductivity.
Automotive Industry: Commonly used for creating gears, fasteners, and connectors in automotive systems.