Common Copper Screw Materials: H59, H62, H65, Brass, Red Copper, and Bronze — What’s the Difference?

Red Copper (Pure Copper)

Red copper, also known as pure copper, contains over 99.9% copper. Its atomic structure gives it exceptional ductility and excellent electrical and thermal conductivity.However, this "purity" comes with a downside,low strength (tensile strength around 200 MPa) and high plasticity, making it unsuitable for applications requiring strong fastening force. Thus, its use in screws is very limited-mainly for electrical components that demand top level conductivity, such as connections inside high voltage switch cabinets. Here, conductivity comes first, and mechanical strength is secondary.

Brass

Brass is an alloy of copper and zinc, and it's the most widely used material for "brass screws." Adding zinc significantly increases strength and hardness, but slightly reduces conductivity and ductility. By adjusting the copper–zinc ratio and adding other elements, we get a series of alloys with different properties-H59, H62, H65, and so on. These designations refer to different grades of brass.

Brass properties directly depend on zinc content, with Higher zinc,brass will be more higher strength and hardness, but lower ductility.When zinc exceeds 45%, the material becomes brittle and difficult to process.Therefore, most screw materials keep zinc below 40%.

BTW, brass (e.g., C3604) contains a small amount of lead, which greatly improves machinability,making screw heads full and threads sharp. However, due to environmental regulations such as RoHS, lead-free machinable brass (e.g., C3452, containing bismuth or silicon) has become mainstream in export markets.

H59 brass is the most economical and practical

H59 brass has the lowest copper content and the highest zinc content, making it the most cost-effective. This high zinc content also provides higher strength and hardness, but at the expense of reduced ductility and toughness, and it may become brittle at low temperatures. Its corrosion resistance, particularly its resistance to dezincification corrosion, is relatively weak among brasses. Therefore, it is suitable for cost-sensitive applications in normal dry environments, where mechanical properties are not critical. It is not recommended for outdoor use, humid environments, or critical load-bearing structures.

H62 brass is the most widely used brass

H62 brass offering an excellent balance between copper content, strength, ductility, corrosion resistance, and cost. It has good room-temperature ductility, while also providing sufficient strength and hardness for most general applications. It is the most common and widely used copper screw material in the hardware market. If you're unsure, H62 is a safe bet in most cases. It is suitable for plumbing, general valves, low-voltage electrical appliances, and general building structures.

H65/H68 brass has a higher copper content

H65/H68 brass's color is closer to gold. Its excellent plasticity and toughness make it well suited for forming processes like cold heading and drawing, producing clear, beautiful screw threads. Its corrosion resistance is also superior to H62. H65 is an ideal choice for screws with complex shapes or requiring extremely high thread accuracy and surface quality. It is also commonly used in decorative parts and bullet casings.

Silicon bronze is no longer just a copper zinc alloy. It's a copper,silicon,tin,manganese system.Adding silicon significantly enhances strength, fatigue resistance, and stress corrosion cracking resistance, while tin improves seawater corrosion resistance. Silicon bronze achieves high strength comparable to medium carbon steel while maintaining excellent corrosion resistance. It is the top choice for marine, offshore, and chemical environments where both mechanical reliability and corrosion resistance are essential.

Comparison of Common Copper Screw Materials

Material	Main Components	Core Features	Advantages	Disadvantages	Typical Applications
H59 Brass	~59% Cu, balance Zn	Economical, decent strength	Lowest cost, good machinability	Poor corrosion resistance, brittle in cold	Indoor parts, light-duty fittings, furniture
H62 Brass	~62% Cu, balance Zn	Best overall balance	Good strength, ductility, corrosion resistance	Not suitable for marine environments	Valves, plumbing, electrical parts, hardware
H65/H68 Brass	~65–68% Cu	High ductility and toughness	Excellent cold workability, better corrosion resistance	Slightly lower strength, higher cost	Precision screws, decorative parts, casings
Red Copper (T2)	>99.9% Cu	Pure copper	Top conductivity, excellent ductility	Low strength, high cost	Electrical connections, conductive parts
Silicon Bronze (C65500)	Cu–Si–Sn alloy	Marine-grade performance	Extremely high strength & corrosion resistance	Very expensive	Marine hardware, offshore platforms, chemical plants

 

How to find the right material?(5 steps)

1. What is your application environment? (This is the primary question.)

For ordinary indoor/dry environments: H62 is the most cost-effective choice. For humid environments/frequent water contact: Prioritize brass grades H65 or higher. For highly corrosive environments such as seawater and chemical plants: Silicon bronze is a must. For extremely low-temperature environments: Avoid H59 and choose H65 or silicon bronze for its greater toughness.

 

2. What is your primary functional requirement? (Conductivity or mechanical strength?)

If conductivity is your primary requirement and your budget allows, choose red copper. Otherwise, we generally consider brass with a higher copper content for better conductivity. If fastening and load-bearing are your core requirements: Choose between H62, H65, and silicon bronze, depending on the severity of the environment and your budget. Generally, H62/H65 is used for standard strength (≤400 MPa), while silicon bronze is used for high strength (≥500 MPa).

 

3. Is the application intended for a special environment?

If the working temperature: Is it at low temperature (<-20℃)? Avoid using H59 with poor toughness. Antibacterial requirements: Medical, food equipment? All copper alloys have varying degrees of antibacterial properties, but the surface finish must be ensured. Non-magnetic requirements: Electronic laboratories, MRI equipment? All copper alloys are non-magnetic materials. Industry standards: Drinking water (NSF/ANSI 61), ships (classification society certification), etc. have specific material requirements.

 

4. What is your budget?

The price of copper materials is generally silicon bronze/red copper>H65>H62>H59. If your budget is sufficient and you want long-term use, I recommend choosing a material with better performance within the allowable range. A one-time investment can save the trouble of subsequent repairs and replacements.

 

5. Are there any special industry standards or certification requirements?

For example, parts that come into contact with drinking water may require NSF certification, and marine supplies may have classification society specifications. These standards usually directly specify or recommend the applicable material range.

 

Our factory serves as the core base for the precision manufacturing of copper products, integrating advanced equipment, strict quality control, and efficient production capacity. We possess a complete production line covering the entire process from raw material smelting and continuous rolling to precision drawing/cutting, with key equipment including large-tonnage hydraulic stretching machines, high-precision CNC machine tools, and automated surface treatment systems. This enables the large-scale and customized production of a wide range of products such as copper rods, tubes, plates, strips, and wires. The factory strictly adheres to the ISO quality management system and is equipped with testing instruments such as spectrometers and mechanical property testing machines to monitor process parameters and product performance throughout the entire process. Digital production management is achieved through an ERP system and visual dashboards, ensuring timely order delivery. Furthermore, we implement a green manufacturing philosophy, equipped with exhaust gas treatment and scrap recycling systems, committed to providing customers with high-quality and sustainable copper material solutions.

We employ professional and reliable packaging solutions to comprehensively protect the integrity of all types of copper products during long-distance transportation and handling. For copper rods and tubes, we use moisture- and rust-proof materials for wrapping, secured with sturdy wooden crates or steel strapping to prevent bending and deformation. Copper plates and strips are sealed with waterproof paper or plastic film, protected with edge guards, and then fixed on customized wooden pallets or metal racks to avoid surface scratches and moisture. Copper wires are neatly wound on specialized reels, wrapped with moisture- and rust-proof film, and reinforced at the edges. All packaging is designed according to export standards, with clear labeling to ensure the safe delivery of goods to our global customers.

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