Brass is an alloy of copper and zinc. The golden hue gives it a similarity to gold, but this compound is much cheaper. Pure copper is more expensive than brass. This is due to the lower cost of zinc, which is part of brass. The resulting alloy has characteristics that copper does not have at a lower price.

The alloy is resistant to impact external environment. However, it requires varnish to be applied to the surface, as it turns black over time. Due to its ductility and hardness, it is used both in industrial production and for the manufacture of costume jewelry as decorations.

Brass fittings

The main components of brass alloy are copper and zinc. The proportional components of these metals may be different. The amount of zinc varies. Its minimum value is 20%. The maximum reaches 50%. At the same time, the alloy changes its color: it can be golden, yellow or green.

The percentage of zinc is so important that it can change the characteristics of the material. This refers to its ductility and hardness.

Structure and composition

The composition of the alloy is formed from the phases:

1. Alpha phase. Zinc content up to 35%
2. Beta phase. The presence of zinc is up to 50%. The composition also includes tin - 6%.

In some cases, a single alpha phase is present. Depending on the change percentage composition main components, the structure of brass can simultaneously consist of 2 phases - alpha and beta.

The chemical composition of brass, in addition to copper and the main alloying element zinc, includes additives. These include alloying elements: aluminum, iron, manganese, lead, silicon, nickel. They make up a small percentage of the compound. Each of them affects the characteristics of the material.

Properties and characteristics

The main quality in the characteristics of brass is its corrosion resistance. But it also has other properties:

1. The ability of the alloy to withstand aggressive environments, especially after coating the surface with varnish.
2. Strength of brass.
3. Plasticity of the alloy.
4. The ability of the material to be processed by pressure. The process is carried out both hot at high temperatures and cold.
5. The alloy can be subjected to resistance welding and soldering.
6. Thermal conductivity, which increases with increasing percentage of copper.
7. Melting point, which is 880–950 degrees. With less zinc added, the melting point decreases.
8. The material has non-magnetic properties.

The main factor in the hardness and ductility of the joint is zinc. An increase in its quantitative content is directly related to an increase in strength characteristics. Plasticity increases only up to a quantitative zinc content of 36%. With a subsequent increase to 45%, this indicator decreases.

In order to increase the hardness of the alloy, heat treatment called hardening. It helps not only to increase the strength index, but also relieves internal, structural stresses.

Alloying additives affect the performance characteristics. Their influence is indicated in the table:

Marking

There are 2 types of alloys:

1. Two-component. The main components are copper and zinc. They are marked with the letter L. Next are numbers indicating the amount of copper in percent. L60: contains 60% copper, and the remaining 40% zinc.
2. Multicomponent. In addition to the main components, alloying elements are added. Also in front is the letter L. Then follows a list of additives. At the end, numbers are written through a dash indicating the percentage of each component. The amount of zinc is not indicated, but calculated. For example: Brand LAZhMts66-6-3-2 has 66% Cu, 6% Al, 3% Fe and 2% Mn. By calculation, the amount of zinc is determined to be 23%.

Advantages and disadvantages

Brass alloy has characteristics that are positive in one case and negative in another. They consist of the following:

1. Light weight. This quality, together with high strength, is used in certain industries.
2. The alloy has good ductility.
3. Low cost.
4. Corrosion resistance decreases with increasing amount of copper.
5. Thermal conductivity indicators are lower than those of pure copper and bronze.

Production of material

All components that make up the alloy have different melting points. This creates difficulties when melting brass. During the work process, components are added in a certain sequence.

The production scheme looks like this:

1. Extraction of copper and zinc from ore.
2. Fuse. The copper is heated first, and then the other components.
3. Forming ingots by pouring molten metal into molds.
4. They arrive at the rolling shop, where the metal is processed in order to deform the ingots.
5. Annealing and etching.

Areas of application

Brass is used in the following areas:

1. Making jewelry from brass. Despite the fact that in the jewelry business only costume jewelry is made from it, the demand for such products is great.
2. Due to its plasticity, furniture decorations are forged from it. Fittings are also manufactured.
3. If the zinc content is 40%, the alloy is used in shipbuilding, watch movements and aircraft construction.
4. Water taps, mixers, and fittings are made from it.

Brass faucet

How to distinguish gold from brass

Even though gold and brass look similar, there are ways to tell one from the other. This is checked as follows:

1. Gold has a more saturated color. In addition, over time, brass darkens because it oxidizes in air, but gold does not.
2. If you put a magnet near it, brass will be attracted, but gold will not.
3. Brass has a higher density, which means it is heavier. This is noticeable when throwing pieces of metal in your palms.
4. Availability of sample.
5. If you test with acid, the gold will not react and the brass will discolor.

How can you tell the difference between a brass alloy and a bronze alloy?

Sometimes it is necessary to distinguish bronze from brass. Bronze bushings are used as bearings.

There are methods for this:

1. Bronze is darker in color and significantly heavier. This is noticeable when tossing.
2. Bronze products are harder. The area of ​​the chip will be coarse-grained. The fracture of the brass part will be smooth.
3. Take 2 test tubes with the reagent. Bronze shavings are placed in one, brass shavings in the other. After heating, a white precipitate will appear in the first. In the second, nothing will happen.
4. When brass shavings come into contact with sea salt, they change color. No bronze filings.

Brass is an alloy that is no longer possible to live without in everyday life. Metal is included in technological process many details industrial production, and replacing it is not so easy.

The main components - copper and zinc - are used in proportions of 70% and 30%, respectively.

Over 50% of the zinc used in brass production comes from recycled waste. Technical brass consists of 48–50% zinc. According to their composition, they are divided into alpha and alpha + beta brass:

• Single-phase alpha brasses consist of 35% zinc.
• Two-phase 47-50% zinc and contain no more than 4% lead.

Brass (yellow copper) is a multicomponent composition based on a copper alloy. One of the most used and most useful alloys. According to the classification of metallurgists, it does not belong to the category of bronze.

The second main component is zinc, sometimes tin is added (much less often than zinc, otherwise it will turn out to be classic tin bronze). Sometimes brass etching contains manganese, lead, nickel, iron and other elements.

If the surface of brass is not varnished, it quickly darkens in the open air, but in its mass it resists the action of the atmosphere. It has a beautiful yellow tint and is easy to polish. Whether it is easy or difficult to forge depends on the composition of the material and the processing temperature. Some types of material can be processed only in a cold state, other materials in a heated state or do not want to be processed at all.

2 Chemical composition of brass

Brass is composed of zinc and copper. It is often compared to bronze because the composition of bronze and brass shares the same component - copper. Although brass, whose composition differs from bronze, includes zinc as a second element, not tin.

Zinc is a constituent element of the secondary subgroup of the 2nd group of the IV period of the periodic table of chemistry. Mendeleev's elements. Atomic number – 30. Production originated in India around the 12th century. The short symbol is Zn (Zincum). IN normal conditions a very brittle transition metal with a light blue color (darkens in open air and becomes coated with a thin layer of zinc oxide). Zinc does not occur in nature as an independent metal.

Copper is a constituent element of group 11 of period IV of the periodic table of chemistry. Mendeleev's elements. Atomic number – 29. Abbreviated designation – Cu (Cuprum). It is an elastic transition metal with a light golden color (in the presence of an oxide film, copper becomes yellowish-red). Some of the first copper products were discovered during archaeological excavations of the ancient settlement of Çatalhöyük (7,500 BC)

Thanks to zinc and copper (in addition to the main α-solution), a number of stages are formed electronic formβ, γ, ε. Typically, the structure of brass consists of α- or α+β’- phases:

• α-phase is a stable solution of zinc and copper with a crystalline face-centered cubic copper lattice (fcc).
• β'-phase is a structurally stable solution based on the chemical combination of CuZn with a concentration of 3/2 and a simple unit cell.

Dependence on processing temperature:

• When the temperature is high, the β phase has a chaotic atomic order and a large volume of homogeneous mixture. In this state, it (the phase) becomes very elastic, if the temperature is less than 454–468 °C, the structure of the zinc and copper atoms acquires order and is designated β’.
• The β’ phase is fundamentally different from the β-phase and is more rigid and brittle; the γ-phase consists of the electron combination Cu5Zn8.

Single-phase brasses are highly elastic; The β' phase is stronger and less elastic.

Separation depending on the amount of zinc in the alloy:

• If the alloy contains up to 30% zinc, both hardness and elasticity increase simultaneously. After which the elasticity decreases, first due to the compaction of the α-hard solution. Then its immediate decrease occurs, this is due to the discovery of a fragile β’-phase in the structure. Further, the hardness increases until the zinc content does not exceed 45%. Then it drops sharply.
• Most brasses are very easy to work with. The single-phase category is especially distinguished by its elasticity. Brasses change structure at low and high temperatures. Although in temperature conditions of 300–700 °C a “brittle zone” occurs. In this temperature regime, deformation does not occur.
• Two-phase brasses are very ductile when heated above the β'-transformation temperature conditions (especially above 700 °C). For growth technical indicators and chemical stability, additional elements are often mixed into them, for example: aluminum (Al), manganese (Mn), nickel (Ni), silicon (Si) and others.

3 Brass manufacturing process

Brass is very easy to forge, very tough and malleable, and can be deformed into various shapes when struck by a hammer, stretched into wire, or simply stamped into a wide variety of parts. It melts and casts relatively easily at temperatures below the melting point of copper.

The standard manufacturing procedure occurs:

• In crucibles made of fire-resistant clay. Crucibles are heated in shaft or flame furnaces.
• Directly in reverberatory furnaces (without the use of crucibles).

At the moment of mixing copper and zinc, the alloy is cast into prepared sand molds. A certain part of zinc always evaporates, which must be remembered when forming the composition of the metal.

4 Applications of brass

Tompak is a deformable type of brass. It consists of 88–97% and 10% copper and zinc, respectively. Tompak is characterized by:

• high plasticity;
• rust resistance;
• low friction force.

Copper alloys, which consist of 10–20% zinc, are called semi-tombacs.

Tompak can be easily welded with steel and other noble metals. It is used to make a combination of steel and brass. Due to its golden hue, tombac is used to make art products, all kinds of medals and accessories. Tompak is easily gilded, enameled and pressure treated in low and high temperature conditions.

The famous Scottish scientist Andrew Ure gave several examples of tombac content in the 19th century. There are three options for the alloy of copper, zinc, lead and tin in proportions:

• 82/18/1,5/3;
• 82/18/3/1;
• 82,3/17,5/0/0,2.

Foundry brass – intended for the production of semi-finished products and shaped products by casting. Contains 50–81% copper. The following diluting elements are used: silicon, aluminum, iron, manganese, tin and lead. Main characteristics:

• does not rust;
• resistant to friction with other materials;
• excellent mechanical properties;
• easy to handle due to its liquid state;
• low tendency to disintegrate the material.

Cast brass is often used for mass production:

• reinforcement elements (for example cast);
• large worm screws;
• pressure screw nuts;
• rust-resistant parts;
• bushings;
• separators;
• bearings;
• parts operating at temperatures not exceeding 300 °C;
• fittings (hydraulic system of cars).

5 Automatic brass

Automatic brass – lead type alloy Compound:

• 0.3–0.8% – lead;
• 57–75% – copper;
• 24.2–42.7% – zinc.

The addition of lead during machining promotes the formation of short and loose chips, which reduces wear on the separating mechanism and allows for high-speed processing of parts (hence the name).

The mechanical properties of automatic brass depend on its components and state of aggregation:

• soft;
• hard-worked.

Automatic brass is available in the form of:

• ribbons;
• stripes;
• rods;
• sheets.

In turn, the sheets are used to make:

• nuts;
• bolts;
• parts for watches and other mass-produced products.

So, we found out that brass consists of zinc and copper. We figured out how to make it correctly. We figured out what types of brass there are and what is the best use for each type.

Similar to gold, but much cheaper. Known back in Ancient Rome, but rediscovered in the 18th century. Combining the excellent properties of two chemical elements, brass has found a wide range of applications.

Compound

Despite its noble color and appearance, brass is an alloy of copper and zinc; there is no gold or other precious metals. In addition to these two components, other substances are used to improve the physical and chemical properties: manganese, tin, iron, silicon, nickel, lead, etc. As a rule, the proportion of these impurities is no more than 10%. Otherwise, the composition of brass is more or less constant, although the ratio of components may vary. Typically, the zinc content does not exceed 30-35%, but in technical alloys its share can reach up to 50%.

Properties

The main consumers of copper, and therefore brass, are economically the developed countries Europe, as well as the USA, China, Japan and some others. IN last years The demand for these substances is only growing, primarily due to Asians. Having made a giant leap in the mid-2000s, Cu prices remain at their previous record highs. However, a peak in supply is expected in 2016, which is likely to trigger a decline in prices.

Metals and alloys are literally the basis of human civilization. Pure metals are not very often used in national economy, but alloys are used everywhere. This is not surprising, since the alloy combines the properties of several substances in the best proportion. This article talks about the production and processing of the melt, preparation of the material, composition, properties, etc.

Structure and chemistry The composition of brass is a very important issue. Brass is a two- or multicomponent solid solution - an alloy based on zinc. Brass has been known for an extremely long time, even over time Ancient Rome, and is still in use today. Its properties depend on its quantitative composition.

The traditional composition of brass is 70% copper and 30% zinc. Zinc improves the mechanical and technological qualities of the alloy, and at the same time reduces its cost, since it is a more affordable metal. In practice, the use of solutions with a zinc content of more than 50% is rare.

Brass has a very beautiful golden color. However, without a protective layer - varnish, for example, it darkens quite quickly. In quite large quantities In some cases, this property is not considered a disadvantage.

The alloy is marked depending on its composition. Brass is designated by the letter “L”, followed by a number indicating the proportion of copper – 70, for example. If the alloy has been alloyed, then all additives are indicated by decreasing their proportion, and then the composition is indicated. For example, LAZH60-1-1 means that brass contains 60% copper, and that the alloy is alloyed with aluminum - 1%, and iron - 1%.

This video will tell you how brass burns and how the material is melted at home:

Classifications based on zinc content

Compositions are classified according to the proportion of zinc:

• if its content is 5–20%, brass is called red - tompak;
• if the proportion of zinc ranges from 20–36%, the alloy is called yellow brass;
• an alloy with a zinc share of 48–50% is called technical.

In the production of brass, more than 50% of zinc is obtained from the processing of recycled materials, so the alloy can be classified as a fairly environmentally friendly product.

Separation by quality of additional ingredients

Alloys are divided according to the quantity and quality of additional ingredients.

Two-component

Two-component ones include only copper and zinc. Here the properties of the alloy are strongly influenced by the phase composition. Copper can dissolve no more than 39% of zinc. Moreover, as the temperature increases, the solubility decreases, and only a single-phase solution is formed - the α-phase. Such alloys are called α-brasses; they are characterized by high ductility and are quite strong if the proportion of zinc reaches 30%.

As the proportion of zinc increases, part of the metal no longer dissolves and a two-phase solution is formed - α + β'-brass. The β’ phase is harder, but also more brittle, so this alloy is stronger, but loses its ductility.

This feature also determines the unusual processing method. So, for cold processing - shaped profiles, wire, only α-brass is used, since its ductility is high at low temperatures, and in the temperature range from +300 to +700 C it drops sharply, so it is useless to deform brass when heated. But α+β’-solutions are processed at high temperatures.

Multicomponent

Multicomponent additives may contain:

• nickel – increases corrosion resistance;
• – reduces strength, but together with lead gives anti-friction properties;
• lead – no more than 4%, reduces strength, but facilitates machining. Such brass is often called automatic;
• iron – reduces grain growth, which improves the mechanical properties of the alloy;
• – no more than a share. Otherwise, the alloy turns into one of the varieties. Tin gives the alloy resistance to action sea ​​water, for which such brass received the name marine;
• manganese – increases corrosion resistance and promotes strength.

Metal production

Since the main component of brass is copper, the material is classified as a copper alloy. The production scheme is quite simple. However, from a technological point of view, the process turns out to be complex, since it requires very strict adherence to temperature conditions and processing of raw materials and workpieces.

IN general view getting the alloy looks like this:

• melting copper in special crucibles;
• introduction of zinc;
• introduction of additional components - iron, nickel;
• pouring into molds;
• hardening - by stamping or drawing.

The matter is further complicated by the fact that the conditions for obtaining alloys largely depend on the composition of the alloy and its purpose.

Below is a video about melting brass at home.

The video below explains how to produce and melt brass at home:

Technologies

The production of brass should begin with the extraction of copper from copper ore. In fact, this is a complex polymetallic raw material, in which the proportion of copper is small. The main components are waste ore, iron and copper, and the first step in obtaining brass is to separate the copper from the other components.

Receiving raw materials

The process is extremely complex, since its goal is to transfer raw materials from a single multicomponent mixture into a heterogeneous system consisting of several phases with different compositions and different properties. Only after this the phases can be separated from each other and compositions suitable for further use can be obtained. A variety of methods are used for this: in some cases, the extracted phase is additionally enriched with the “main” metal, in others, on the contrary, it is depleted, in others they resort to mechanical separation methods when the phases, for example, differ in solubility, and so on.

The following two methods are most often used.

• Pyrometallurgical The technology involves processing copper ore with subsequent refining of blister copper. It includes smelting, converting copper matte, fire refining - essentially removing large impurities, and electrolytic refining. The latter allows not only deep purification of copper, but also the extraction of any associated components if they are of value.
• Hydrometallurgical The method is used when using low-grade copper ore. Its essence comes down to leaching - the effect of sulfuric acid, iron sulfate. To do this, the ore is crushed and dissolved in solvents, and then the copper is extracted either by cementation - the deposition of pure copper on iron, for which ordinary scraps of sheet and wire are used, or by electrolysis.

In this way, it is possible to completely extract copper from even the poorest ore.

Obtaining zinc also has its own characteristics, but, in general, is a simpler process.

We will tell you below whether it is possible to weld brass at home and how it is produced at a factory.

Alloy production method

Smelting of brass depends on the composition of the alloy. Here it is necessary to take into account both the different boiling temperatures of metals and different oxidation abilities.

• Melting with pure metal– when using recycled metals, the charge can be loaded in any order. If there is pure metal in the charge, then copper is melted first, and then the circulating metals. Zinc and, if any, are introduced into the melt last, preheated to 100–120 C. Melting is carried out under a layer of charcoal, which is loaded with the first portion of the charge.
• Melting silicon brass- this composition tends to absorb reducing gases, so charcoal is not used here. Melting is carried out under a covering flux - glass or borax - to prevent interaction with oxygen. Copper is loaded into the furnace first, then waste and copper-silicon master alloy. Zinc is loaded into the melt last, after the slag has been removed.
• Smelting manganese brass– carried out under charcoal or glass flux. In this case, manganese is introduced last along with alloys, after all other ingredients are melted.

Sheet production

The usual form of brass production is sheets and wire. In general, the process goes like this.

1. Ingots from the melting shop go to the rolling shop, where they are heated in a furnace to a deformation temperature of –790–830 C.
2. At the mill, the ingots are deformed to the size and thickness of the workpiece.
3. The workpiece in the form of a roll is supplied for welding and then subjected to double-sided milling.
4. Then the semi-finished product is returned to the rolling shop, where it is rolled in a three-stand rolling mill until the specified sheet thickness is obtained.
5. The finished strip is cut into measured lengths.
6. The sheets are annealed in chamber furnaces and then pickled in pickling baths.
7. The material is deformed again to its final thickness and etched again.

Read below about the equipment for casting brass at the brass manufacturing plant.

Necessary equipment and raw materials

Since copper is a metal in demand, production uses methods for extracting copper from both rich and very poor ores. So the raw material can be almost any ore that contains at least some amount of metal.

Producing brass is a multi-stage and technologically complex process. So the equipment here includes both the latest technological lines and the most traditional foundry tools.

• For melting brass the best option is an induction channel furnace or an electric resistance crucible furnace. This equipment consumes a minimum amount of electricity based on the production of 1 kg of alloy and allows for minimal overheating of metals. The worst choice is electric arc furnaces.
• To heat the ingots before deformation, a methodical furnace is used - here heating from 650 to 1200 C is possible.
• Hot rolling mill – the working module is the working stand in which hot rolling is carried out. The equipment can also be used for cold rolling of sheets and strips.
• Welding line - equipment depends on the parameters of the workpieces and finished products.
• Milling machine – for double-sided milling of welded strip.
• A cold rolling mill is usually a three-stand mill. To service it, you also need a hoist - it feeds rolls into the mill, a storage roller table - with its help, a batch of strips of the same brand is assembled, and an input section - an unwinder, a folder, a straightening machine, and so on.

In addition, the line must include equipment - from a cart to a loading crane, which ensures the movement of ingots, blanks, rolls and sheets between technological units.

At the stage of obtaining alloys, you will also need mechanical tools:

• bell - a device for cleaning and degassing alloys, perfect for introducing refining fluxes;
• slag – a tool for removing slag from the surface of the alloy;
• pouring spoon;
• two-handed ladle – a device for casting non-ferrous alloys.

The production of brass, or rather, the sheets and wire necessary for the manufacture of finished products, is a technologically complex and labor-intensive process. It is possible to obtain an alloy that meets GOST requirements only at large non-ferrous metallurgy enterprises.

The video below shows brass being cast into a mold: