How Brass is Made and Used in Manufacturing(custom cnc parts Valentine)
- source:BAGANZ CNC Machining
Producing Brass Alloys
Brass is made by combining molten copper and zinc in varying proportions to create different brass alloys. The amount of zinc content, known as the zinc equivalence, determines the properties and classification of the brass alloy. Here are some common brass alloys and their zinc content:
- Red brass - 15% to 20% zinc - Used for plumbing fittings and steam fittings
- Yellow brass - 33% zinc - Most common type used for everyday brass objects
- Naval brass - 39% zinc - Heat resistant and used for ship propellers and gears
- Cartridge brass - 30% zinc - Used for making ammunition cartridges
- Low brass - 5% to 20% zinc - Cheaper substitute for bronzes
The zinc content affects the color, hardness, melting point, ductility, strength, and machinability of the alloy. Other elements like tin, manganese, silicon, aluminum, lead, and iron may also be added in small amounts to produce leaded brass, free-machining brass, and other specialty alloys.
Melting and Mixing
To produce brass, copper is melted and heated to about 1,900°F to reach a molten state. Zinc is then added and thoroughly mixed in precise amounts to achieve the desired zinc content. Most commercial brass is made by this hot-mixing process using large furnaces and careful control of temperatures and zinc additions. For some specialty alloys, the copper and zinc may be pre-mixed as powders or shavings before being melted together.
The molten brass can then be poured into molds or continuously cast by pouring the brass into water-cooled rolls to form long sheets or rods. The cooling and solidification process is carefully controlled to ensure the right crystalline structure and prevent cracking or voids in the solid brass. Proper mixing, pouring, and cooling helps maximize the ductility and workability of the finished brass alloy.
Forming Brass Objects
Brass can be formed into a wide array of products using several processes:
Extrusion - Brass rods are pushed through a steel die to form long lengths of brass stock with a specific cross-section such as bars, tubes, and specialty profiles.
Rolling - Preheated brass sheets are passed through successive rolling mill stands to reduce thickness and achieve a desired temper and mechanical properties.
Drawing - Annealed brass tubes or rods are pulled through a die or series of dies to reduce diameter and increase tensile strength.
Forging - Brass stock is pressed into high-pressure dies to form a rough shape then annealed repeatedly as working continues to form complex forged parts.
Stamping - Sheet brass is blanked and drawn into shapes using stamping presses and dies to make components like washers, contacts, and brackets.
In addition to these forming processes, brass parts can also be machined with lathes, mills, drills, and other cutting tools to achieve final dimensions and surface finishes. Machining is typically done on annealed brass to improve cutting performance and prevent cracking.
Brass for Architecture, Plumbing, and Decor
Brass has been used since ancient times for architectural fixtures, decorative items, altars, coins, musical instruments, and more. The impressive gold-like sheen and excellent acoustic properties make brass a versatile metal for functional and ornamental use. Some specific examples include:
- Door knobs, door handles, and kick plates
- Faucets, valves, fittings, and plumbing fixtures
- Lighting fixtures like lamps, chandeliers, and sconces
- Bells, gongs, bugles, trumpets, trombones, and other musical instruments
- Sculptures, statues, plaques, memorials, and architectural accents
- Locks, hinges, bolts, screws, nuts, fasteners, and hardware
- Altars, crosses, menorahs, vases, bowls, and religious symbols
- Bar tops, railings, frames, furniture accents, and decor
Over time, a soft patina forms on brass from oxidation and contact with air and moisture. This living finish adds an antique charm, depth, and character to brass objects. The malleable and acoustic properties of brass alloys have made brass a mainstay material that enhances buildings and artwork across all decorative styles and time periods.
Brass for Machinery, Electronics, and More
Beyond its decorative uses, brass's strength, wear resistance, and anti-galling properties make it an important metal for precision parts across many industries. Some examples include:
- Gears, bearings, bushings, worm gears, and clock parts
- Electrical contacts, terminals, springs, and other components
- Ammunition and bullet casings, primers, and firearm components
- Plumbing fittings, valves, pipe nipples, elbows, and compression fittings
- Marine components like propellers, fittings, fasteners, impellers, and shafts
- Telecommunications copper alloy wire, RFI shielding, and radio components
- Automotive radiator cores, terminals, valves, carburetor components
- Refrigeration, HVAC, and heat exchanger components
- Metal bellows, diaphragms, thermocouples, safety valves
Machinists rely on cartridge brass and free-machining brass alloys to achieve tight tolerances and superior surface finishes on parts. The excellent formability, machinability, and dimensional stability of brass has led to its utilization across many critical industries and applications.
Brass remains a go-to material for both decorative and functional manufacturing. Understanding how the proportions of copper and zinc affect the properties and workability of the alloy gives insight into why brass has been relied on for thousands of years. Advancements in production processes and machining technologies will ensure brass continues to be valued in manufacturing for generations to come. CNC Milling