How Much is Brass and How is it Produced?(cutting tool for lathe Tiffany)
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Brass Prices
The price of brass depends on the market price of copper and zinc as well as supply and demand factors. On commodity markets, copper futures currently trade for around $4.50/lb while zinc futures are around $1.60/lb. So with a typical brass composition of 70% copper and 30% zinc, the base metal content comes out to around $3.80/lb. However, this doesn't account for the costs of manufacturing and fabrication which can vary. Some example brass prices:
- Brass sheets, 0.125" thick - $5.50-$7.00/lb
- Brass rods, 0.5" diameter - $4.50-$6.50/lb
- Brass tubing, 1" diameter - $6.00-$8.50/lb
- Brass fittings (elbows, tees) - $8.00-$15.00/lb
So as you can see, brass products can range from just a couple dollars per pound for basic forms like rod or sheet up to $15/lb or more for finished fittings and components. The manufacturing process also affects the price. More on that next.
Brass Manufacturing Processes
Here are some of the common ways that brass is produced from copper and zinc:
1. Direct alloying - This is the most straightforward approach where purified copper and zinc are melted together at around 900°C to form a liquid brass alloy. The proportions are controlled to get the desired composition. Direct alloying produces a consistent, homogenous brass but requires energy intensive heating.
2. Cementation - In this process, solid copper is heated with zinc oxide and carbon. The zinc oxide reacts with carbon, releasing zinc vapor that is absorbed by the copper. This diffuses zinc into the copper matrix to create brass. It requires less heat but can result in an uneven distribution of zinc.
3. Electrolytic - Uses electroplating to deposit layers of zinc onto solid copper. With precise control of the electroplating process, a uniform brass coating can be achieved. The copper provides a structural base for the brass coating.
4. Powder metallurgy - Copper and zinc powders are mechanically mixed, pressed into a mold then sintered which fuses the metal particles together into a solid brass part. This method allows complex shapes to be formed. Porosity can be an issue requiring infiltration to fill voids.
The manufacturing process affects the cost, with methods like direct alloying and electrolytic plating producing higher purity, more uniform brass but at a higher price. Powder metallurgy and cementation use less energy but the brass can have more impurities and inconsistencies.
Brass Production Steps
To understand the full brass manufacturing process, here are the typical steps:
1. Procurement - Obtain pure copper and zinc meeting specifications for composition and quality. Scrap brass can also be recycled.
2. Alloying - Combine copper and zinc using one of the methods described above - direct melting, cementation, electrolytic plating, powder metallurgy etc. This produces the raw brass alloy.
3. Melting and pouring - For cast products, the raw brass is melted and poured into molds to produce castings. Sand casting and die casting are common approaches.
4. Hot working - For wrought products, the brass ingots are heated and worked using processes like rolling, forging, extrusion and drawing to produce plate, sheet, rod, tube and wire forms.
5. Cold working - Wrought shapes can be processed further in the cold state using rolling, stamping and machining to achieve closer tolerances, improved strength and work hardened properties.
6. Annealing - Intermediate annealing steps are often incorporated to soften and restore ductility to the brass as it is being cold worked to prevent cracking.
7. Finishing - Final surface finishing steps like polishing, coating and plating help achieve the desired appearance and corrosion resistance.
8. Fabrication - For end use components, the finished brass stock is fabricated into valves, fittings, fasteners, instruments etc. Joining processes like welding and soldering may be used.
So in summary, making brass starts with procuring copper and zinc raw materials, alloying them together, hot and cold mechanical working, heat treating, surface finishing, then fabricating into final products. The specific path and processes vary by the type of brass item being made and the properties needed. This influences the cost along with raw material prices.
Conclusion
The price of brass ultimately comes down to the underlying costs of copper and zinc as well as the expenses associated with transforming these into usable brass metal. On the commodity markets, brass will typically cost around $4-$5/lb depending on alloy composition. But fabricated brass products can range from just a few dollars per pound for basic stock forms up to $15/lb or more for finished components, valves and fittings. The manufacturing process affects cost as well, with more uniform and refined brass made via methods like direct alloying and electrolytic plating coming at a premium price. So the next time you see a beautiful brass item, you can better appreciate the value from the underlying material costs, shaping processes and skilled fabrication required to produce it. CNC Milling CNC Machining