Brass C220

Brass C220 is a versatile, free-machining alloy that creates high-precision parts in plumbing, automotive, and electrical systems.

Introduction to Brass C220

Brass C220, or cartridge brass, is a copper-zinc alloy with a 70% copper content and approximately 30% zinc. This alloy is highly regarded for its excellent formability, corrosion resistance, and relatively low cost compared to other brass alloys. Brass C220 is commonly used in CNC machining services because of its good machinability, making it ideal for producing complex shapes and parts with tight tolerances. It is especially valued for applications in industries requiring high ductility and moderate strength.

Due to its favorable combination of properties, Brass C220 is widely used in various sectors, including plumbing, electrical, and decorative applications. CNC machined Brass C220 parts make components like plumbing fittings, electrical connectors, and industrial hardware.

Chemical, Physical, and Mechanical Properties of Brass C220

Chemical Composition (Typical)

Element	Composition Range (wt.%)	Key Role
Copper (Cu)	60.0–70.0%	Provides strength, corrosion resistance, and electrical conductivity
Zinc (Zn)	30.0–40.0%	Enhances strength, ductility, and machinability
Iron (Fe)	≤0.1%	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	20–30% 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	310–460 MPa	ASTM E8/E8M
Yield Strength (0.2%)	220–370 MPa	ASTM E8/E8M
Elongation	30–40%	ASTM E8/E8M
Hardness	60–90 HB	ASTM E10
Fatigue Strength	~200 MPa	ASTM E466
Impact Resistance	Good	ASTM E23

Note: These values are typical for annealed Brass C220 and can vary based on specific processing conditions.

Key Characteristics of Brass C220

Excellent Ductility

Brass C220 is known for its high ductility, allowing it to easily form into a wide range of shapes. It is especially suitable for applications that require bending, stamping, or drawing operations.

Moderate Strength and Good Machinability

While Brass C220 offers moderate strength, its key feature is its ease of machinability, making it ideal for high-speed CNC machining. It can be cut quickly with minimal wear on tooling.

Corrosion Resistance

Brass C220 offers good corrosion resistance, especially in environments where exposure to water, air, and mild chemicals is common. This makes it a popular choice for plumbing and electrical components.

Cost-Effective

Due to its relatively low cost compared to other brass alloys, Brass C220 is an economical choice for applications that require large volumes of parts, such as plumbing fittings and electrical connectors.

Aesthetic Appeal

Brass C220 has an attractive golden color, making it ideal for decorative applications such as jewelry, trim, and other visible components in consumer products.

CNC Machining Challenges and Solutions for Brass C220

Machining Challenges

Chip Formation

Brass C220 can produce long, stringy chips during machining, affecting the machining process and productivity.

Solution: Use chip breakers to control chip formation, adjust feed rates, and apply high-pressure coolant to improve chip removal.

Tool Wear

Despite its excellent machinability, Brass C220 can still cause tool wear over prolonged machining operations due to its zinc content.

Solution: Use high-performance carbide tools, adjust cutting speeds, and ensure proper lubrication to extend tool life.

Surface Finish

Achieving a fine surface finish can be challenging when machining Brass C220, especially during high-speed operations.

Solution: Use sharp tools and adjust cutting parameters to achieve a smooth finish, applying light coolant to reduce friction.

Work Hardening

Brass C220 can work-harden if excessive cutting force or speed is applied during machining, making further operations more difficult.

Solution: Use moderate cutting speeds, ensure sharp cutting tools, and apply appropriate cooling techniques to prevent work hardening.

Optimized Machining Strategies

Tool Selection

Parameter	Recommendation	Rationale
Tool Material	Carbide tools with high-speed steel inserts	Carbide tools offer excellent wear resistance and cutting efficiency
Geometry	Positive rake, sharp edges	Ensures better chip removal and surface finish
Cutting Speed	200–300 m/min	Helps reduce tool wear and prevents excessive heat buildup
Feed Rate	0.10–0.15 mm/rev	Ensures smooth cutting and prevents material deformation
Coolant	Flood coolant or air blast	Reduces heat and enhances surface finish

Brass C220 Cutting Parameters (ISO 513 Compliance)

Operation	Speed (m/min)	Feed (mm/rev)	Depth of Cut (mm)	Coolant Pressure (bar)
Roughing	200–250	0.20–0.30	2.0–3.5	25–35
Finishing	250–350	0.05–0.10	0.5–1.0	30–50

Typical Machining Methods for Brass C220

Machining Process	Function and Benefit for Brass C220
CNC Machining	Precision machining of parts with intricate shapes and fine tolerances.
CNC Milling	Ideal for producing slots, grooves, and complex shapes for fittings and valves.
CNC Turning	Used for turning cylindrical parts like bushings, connectors, and mechanical components.
CNC Drilling	Perfect for creating holes for fasteners, fittings, and precise components.
CNC Boring	Ideal for internal machining of parts like bearings and bushings.
CNC Grinding	Provides smooth finishes for components exposed to wear and tear, like gears and shafts.
Multi-Axis Machining	Perfect for producing complex, multi-featured parts for automotive and aerospace applications.
Precision Machining	Delivers high-precision components for mechanical and electrical systems requiring tight tolerances.
EDM Machining	Useful for creating intricate features and fine details in automotive and industrial parts.

Surface Treatment for Brass C220 CNC Parts

Electroplating: Enhances the durability of brass components, ideal for electrical connectors.
Polishing: Achieves a smooth, reflective finish for decorative and functional parts.
Brushing: Creates a matte finish, enhancing corrosion resistance for industrial applications.
PVD Coating: Adds a durable coating to increase wear resistance in high-stress applications.
Passivation: Increases corrosion resistance, especially for parts exposed to chemicals or moisture.
Powder Coating: Provides a thick protective finish for outdoor and decorative parts.
Teflon Coating: Adds a non-stick, chemical-resistant layer, ideal for high-performance mechanical applications.
Chrome Plating: Adds a glossy, corrosion-resistant layer for durable and aesthetically pleasing parts.

Industry Applications of Brass C220

Aerospace Industry: Ideal for creating precision components like fasteners, bushings, and connectors used in aerospace systems.
Electrical & Power: Used to produce electrical connectors, switchgear, and other components exposed to mechanical stresses.
Automotive Industry: Suitable for components like gears, bushings, and connectors used in high-performance automotive applications.