1. Introduction

Brass is a metal alloy with copper and zinc as the main content. The other metals incorporated along with the two main components of the brass makes the distinction for every variety of brass. Brass can be categorized according to its mechanical properties, crystal structures, chemical composition percent and color (Helmenstine, 2015).  Compared to steels, brass alloys are less strong and hard but more machinability superior and corrosion resistant.  Metal alloys with copper as base such as brasses are usually used for wrought and cast forms(Hornbostel, 1991).

The color of brass can range from dark reddish brown to silvery yellow depending on its zinc content. The more the zinc percent is, the lighter the color (Hornbostel, 1991).One type of brass according to its color is the red brass.Red brass is usually comprised of 85% copper, 5-15% zinc, and tin, lead, or iron as the remaining elements. Red brass is a metal alloy considered as brass or bronze hence it has many definitions according to what alloy the term pertains to. The following are the different definition for the term red bras:

  • It can be an alloy made of copper as the main component (85%) with zinc and tin (Bell, 2015).
  • It is an American term for the type of bronzecalled gunmetal which is also a Cu-Zn-Sn alloy only it has varying percent composition (Helmenstine, 2015).
  • It can also be defined as a term used for copper alloys such as the C230000 (Cu-Zn-Pb-Fe alloy)and C836000 or the ounce metal( Bell, 2015).

 

For this report, the term red brass would pertain to the copper alloy C23000 with a maximum composition of 85% copper, 14-16% zinc, 0.05% lead and 0.05% iron.

 

  1. Properties

 

  1. Physical and Chemical Properties

 

Red brass (C23000) is solid in various forms such as sheets, rods, strips  and wires.

The following tables below show the chemical composition and physical properties of C23000.

Table 2.Chemical composition of red brass (C23000).

Element Composition Percent Composition (%)
Copper (Cu) 84-86
Zinc (Zn) balance
Lead (Pb) 0.05
Iron  (Fe) 0.05

(from ESPIMetals.  http://www.espimetals.com/index.php/technical-data/58-brass-compositions)

 

Table 3.Physical properties of red brass (C23000).

Property Value
Density 8.75 g/ cm3
Melting point 988- 1027 °C

(from AZO Materials. http://www.azom.com/article.aspx?ArticleID=6338)

 

 

As shown from the table, ithas a density of 8.75 g/cm3. Red brass having a high copper content compared to other types of brass is known to be an excellent heat conductor and generally resistant to corrosion, dezincification, and season cracking (NBM Metals, 2015).  Because of its high copper content, the copper forms a protective oxide layer on the surface of red brass thus it is highly resistant to corrosion (Bell, 2015).The additional lead component also improves the machinability of the brass while the iron contributes to the hardness of the red brass. The granular structure becomes smaller thus the brass can be shaped many times (How Brass is Made, 2015). Compared to other materials for construction, it has lower melting point range of 988 °C  to 1027°C thus it can be easily casted in different forms and a high machinability rate.

 

 

  1. Mechanical Properties

 

Red brass is known to be one of the most widely used alloys.The table below shows the mechanical properties of C23000.

 

Table1. Mechanical properties of C23000

Properties Values (Metric)
Ultimate Tensile Strength 345 MPa
Elongation at Break 25%
Modulus of Elasticity 115 GPa
Poissons Ratio 0.307
Machinability 30%
Shear Modulus 44.0 GPa
Shear Strength 240 MPa

 

Based on the table above, it shows the good machinability rating of red brass. It has moderate tensile and shear strength that can withstand stress especially when it is used for making pipes and containers. Though it is less stronger compared to other materials such as steel and iron, it can be easily molded in different desired shapes without compromising its strength. Thus it has a good machinability property and is preferred as a material for machines, equipment and designs.  It has also good cold workability

 

  • Considerations

 

  1. Fabrication

 

The composition of red brass for its production usually uses copper scraps and zinc ingots since scraps are relatively cheaper to use.The other components of copper scraps are being considered to produce the desired composition (How Brass is Made, 2015). For the red brass, the components being considered are lead and iron.  The figure below shows the general fabrication flowchart for the red brass.

 

COPPER SCRAPS

 

 

Lead and Iron

ZINC

MELTING

 

 

 

 

 

MOLDING

 

ANNEALING
HOT ROLLING
Figure1. Red Brass Fabrication Flowchart
RED BRASS SHEETS, RODS, or WIRES
FIISHED ROLLING
COLD ROLLING

 

 

 

 

 

 

 

 

 

 

 

 

  1. Melting

Copper scraps ally are first sent in an electric furnace at around 1050 °C. After the alloy has melted, measured amount of zinc are then combined to modify the existing zinc component in the copper scrap and get the desired zinc composition. Lead and Iron are then added to complete the composition for the red brass.

 

  1. Molding

After melting and combining all the individual components, the next stage will be molding. In this stage, the molten alloy is poured in a slab called cakes to be molded. The molded alloy will then be cooled to be subjected in the next operation.

 

  • Hot Rolling

Hot rolling includes reheating the cake into a furnace until the desired temperature where the cake can be remolded is reached. Breakdown rolling is done after reheating.  The alloy cake is fed into steel rollers where the thickness is reduced gradually until it reaches 13mm or less while widening the width of the red brass.

When the desired width and thickness is achieved, the brass is cooled and fed into a milling machine called scalper where the outer surfaces are trimmed. This is done to eliminate the possible dents and impurities on the outer surface due to the reaction of the hot brass with the air.

 

  1. Annealing

In this operation, the brass is subjected to heating again since the ductility or the elasticity of the material might have decreased when it was cooled in the previous operation.  The operation of reheating the brass to reduce its hardness before feeding to further rolling is called annealing. During annealing, the furnace is filled a neutral gas like nitrogen gas to prevent the brass from reacting with the oxygen in the air.

 

  1. Cold Rolling

After annealing, the brass is again subjected to rolling just like in hot rolling only the temperature is lower, hence the name cold rolling.  Cold rolling is done to increase the strength and hardness of the brass by reducing its internal structures. Further rolling is done until the desired thickness is achieved. Some brasses are subjected to acid bath to further clean the brass and remove impurities.

 

  1. Finished Rolling

This is the last stage for the fabrication of red brass. In this stage, the brass is rolled to produce a smooth surface finishing. The finished sheets are cut into different forms depending on the desired final product from of red brass like rolls, rods, or strips

 

(How Products Are Made:Brass, 2015).

 

 

 

  1. Economic

Red brass is commonly produced along with other types of brasses. The main manufacturer of red brass is the United States of America though China has a growing market in brass with a lower price compared in USA.  In local setting, there are no particular Philippine companies who manufacture red brass directly. Most of the red brass are imported and ordered internationally.  The average price of red brass in US is $1.70/lb (Scrap Register, 2015).

 

 

  1. Application to Chemical Engineering

 

Red brass in commonly used as materials for plumbing like fittings, pipe lines, and pipe service lines.  Because of its corrosive resistant and good heat conductor characteristics it is also commonly used in fabrication of heat exchanger shells or tubes and radiator cores. It can also be used as a material for nuts, bolts and thread parts that are used in other equipment (NBM Metals, 2015).

 

  1. References

 

AZO Materials.(2015). Red Brass UNS 23000. Retrieved on October 4, 2015 from AZO

Materials website:  http://www.azom.com/article.aspx?ArticleID=6338 .

 

Bell, T. (2014). Metal Profile: Brass. Retrieved on October 4, 2015 from About.Com website:

http://metals.about.com/od/properties/a/Metal-Profile-Brass.htm .

 

ESPI Metals.(2015). Brass Compositions. Retrieved on October 4, 2015 from ESPI Metals

website:http://www.espimetals.com/index.php/technical-data/58-brasscompositions .

 

Helsmentine 2015.Brass Alloy. Retrieved on October 9, 2015 from

http://chemistry.about.com/od/alloys/a/Brass-Alloys.htm.

 

Hornbostel, C. ( 1991). Construction Materials: Types, Uses and Applications. 2nded. New

York: McGrawHill, Inc.

 

How Products are Made (2015). Brass. Retrieved on October 9, 2015 from How products are

madewesite: http://www.madehow.com/Volume-6/Brass.html .

 

MatWeb Data. (2015). Red brass. Retrieved on October 9, 2015 from matweb website:

http://www.matweb.com/search/DataSheet.aspx?MatGUID=9d91bbdc86ee47aa832743ae52041141&ckck=1 .

 

NBM Metals.(2015). C23000 Red Brass (CDA 230). Retrieved on October 9, 2015 from NBM

Metals website: http://www.nbmmetals.com/products/c23000-red-brass.

 

Scrap Register. (2015). Retrieved on October 15, 2015 from

http://www.scrapregister.com/scrap-price/mix-red-brass/united-states/west-coast/2015-September-11.