Brass Characteristics
Brass exhibits a bright yellow color with incredible corrosion resistance, being this the reason why it is used to replace copper in jewelry and furniture.
The existence of a high concentration of zinc in the alloy drastically reduces the melting point of brass. Nevertheless, this doesn’t affect the properties and makes it suitable for die casting.
A brass alloy contains between 60 and 65% copper, 30 to 34% zinc, and between 1% to 5% of other elements such as lead, used to improve the alloy’s machinability.
Manganese, silicon, iron, and aluminum are used to increase wear and impact resistance.
Brass is a non-sparking alloy, making it an appropriate material to be used for fittings near explosive or flammable fluids.
Brass Alloys And Their Manufacturability
Similar to bronze and commercially pure copper, brass alloys are designated using the UNS numbers. Brass alloys merely composed of zinc and copper are listed from C20500 to C28580.
Tin-Brass alloys, which include admiralty, naval, and free-machining brasses are listed from C40400 to C48600. At last, we have “Silicon Red-Brass” with the numbers between C69400 and C69710.
Each of these alloys, although similar, have their benefits and use a certain concentration of some elements to improve the mechanical, thermal, and electrical properties of the alloys.
1. Arsenical Admiralty Brass (UNS C44300)
The UNS C44300 is composed of 70 to 73% copper, 28% zinc and 0,9 to 1,2% tin. Other constituents are iron, arsenical, and lead. This alloy has very good machinability, formability, and excellent corrosion resistance. The presence of iron also increases its wear resistance. It is widely used for heat-exchanger, condensers, and evaporator tubing in the power generation industry.
√ Manufacturing Processes Performance
| Tensile Ultimate Strength | Tensile Yield Strength | Hardness | Fatigue Strength | Density | Melting point |
|---|---|---|---|---|---|
| 350 MPa | 120 MPa | 59 HRF | 115 MPa | 8,3 g/cc | 900-935°C |
√ Mechanical Properties
| Machinability | Formability | Weldability | Workability | Corrosion resistance | Wear resistance |
|---|---|---|---|---|---|
| 0.3 | Excellent | Very Good | Excellent | Excellent | Good |
2. Free-Machining Brass Full Hard (UNS C36000 H04)
The ideal copper alloy for CNC machining processes. The presence of lead (between 2,5 and 3,7%) improves machinability.
The high concentration of zinc (around 35%) improves ductility, malleability, and electrical properties.
The preferred manufacturing process for this alloy is machining. Nonetheless, it is rolled, stamped, sheet-metal fabricated, and die-cast.
Popular applications include gears, pinions, and any other product that can be fabricated using a machining process.
√ Manufacturing Processes Performance
| Tensile Ultimate Strength | Tensile Yield Strength | Hardness | Fatigue Strength | Density | Melting point |
|---|---|---|---|---|---|
| 530 MPa | 260 MPa | 77 HRF | --- | 8,43 g/cc | 885-900°C |
√ Mechanical Properties
| Machinability | Formability | Weldability | Workability | Corrosion resistance | Wear resistance |
|---|---|---|---|---|---|
| 1 | Good | Excellent | Excellent | Fair to Good | Good |
3. Silicon Red Brass (UNS C69400 H04)
Composed of a considerable amount of silicon (up to 4,5%) and one of the lowest concentrations of zinc in a brass alloy (14,5%) the UNS C69400 keeps the reddish color of bronze and has one of the highest strength-to-weight ratios of copper alloys.
Thermal and electrical properties are considerably reduced, as well as the melting point of the alloy. However, the mechanical properties are considerably improved, making the UNS C69400 attractive to be used in valves and other piping components.
Manufacturing processes for this alloy include die-cast, CNC machining, and forge.
√ Manufacturing Processes Performance
| Tensile Ultimate Strength | Tensile Yield Strength | Hardness | Fatigue Strength | Density | Melting point |
|---|---|---|---|---|---|
| 570 MPa | 270 MPa | 81 HRF | --- | 8,14 g/cc | 820-860°C |
√ Mechanical Properties
| Machinability | Formability | Weldability | Workability | Corrosion resistance | Wear resistance |
|---|---|---|---|---|---|
| 0.3 | Very Good | Excellent | Good | Excellent | Good |
Surface Finishing For Brass
Titanium surface finishing aims to increase its strength, wear resistance. Processes used to enhance titanium are expensive, compared to those used for other materials such as aluminum and steel. The additional costs come from the special equipment required to perform these processes. Surface finishing processes are listed below:
1. Nitriding and oxidation
This plasma-based treatment is performed to increase the wear resistance of titanium alloys. When applied to the surface, plasma thermochemically adds nitrogen to the material’s surface, enhancing its corrosion, fatigue, and wear resistance. It is a costly process, being performed only on few applications such as biomedical implants, in which wear and corrosion are not allowed.
2. Anodizing
The anodizing finishing increases the oxide layer on a material’s surface, improving strength, and wear resistance. It is one of the preferred finishing methods for the aerospace industry because of its low cost and the fact that it doesn’t imply the dimensional change of the product. Anodizing also changes the surface’s color, improving its appearance. This process is mostly used in tubular profiles used for exhausts and heat-exchangers.
3. Electro-polishing
This electrochemical process is used to remove a controlled amount of material from the product’s surface, eliminating surface imperfections while improving corrosion resistance, and cleaning the surface giving it a better appearance. Compared to other processes, electro-polishing is cheaper, and due to the number of benefits related to it, it’s one of the preferred finishing methods for titanium.
Brass Materials: Design And Engineering Tips
Titanium is a versatile element; it is widely used as a primary or alloying constituent for multiple materials. It can be used for both low and high-temperature applications, it has excellent mechanical properties, and its low weight makes it an excellent option for the automotive, aerospace, and marine industries. Here are some tips to help you out with your titanium designs.
1. If increased wear resistance is required, an anodizing treatment is preferred over an NO process. Anodizing costs less and gives excellent corrosion and wear resistance while improving the material’s strength. NO treatment is only applied when the product is to be used in a biomedical implant.
2. Using titanium alloys for the critical components of your design can help you reducing weight and increasing the factor of safety.
3. Titanium is widely used in sheet-metal and extrusion applications. Titanium profiles are very popular for their high strength and corrosion resistance, making them suitable for tubing in the chemical industry.