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Bronzes and Gunmetal

1. Bronzes and Gunmetals

Bronzes are copper alloys and Gunmetals with white tin (Tin) as well as additional elements with little quantity consisting of Lead (lead). For all alloys Copper Lead is called the “Bronzes” and Copper alloys with tin called “Tin-Bronzes”, whereas with the addition of the element Zinc Bronzes called “Gunmetals”.

Bronzes are very easily formed by casting and corrosion resistant properties with the properties of the most important is to have wear resistance properties.

2. Tin Bronzes and Gunmetals
Analysis of the equilibrium diagram indicates that the Copper-Tin Alloys containing Copper Tin (Tin) and 14% classified into the solid solution alloy (solid solution), and if the alloy is cooled very slow nature of the solution will decrease, it is seen that indicated the dashed line (dashed) on the diagram.

So the particles are hard and brittle (δ phase) will be in solid solution (solid solution), this will only happen in practice, where the results of casting alloys containing tin levels above 10% White. But pahse γ can be decomposed with excess lead and enter into solid solution if the alloy is heat-treated (annealing) at temperatures of 3000C with a holding time of up to 1000 hours.

Copper alloy containing tin levels between 14 and 32% of the structure will consist of δ phase and α-phase nature with the nature of the software will be a combination of hard and tenacious. The alloy material is a blend of good material because it has a low melting point.

The diagram also shows that Bronze has a large degree of compaction (indicated on the distance between the solidus line with liquidus line) where the alloy tends to form the core of the structure results casting, alloy core will be formed if each grain tersususn the high melting point and section very rich outer granular composition that has a low melting point, however, the composition of each of these grains can be made uniform through the process of heat treatment (annealing).

Tin-Bronze can be divided into two kinds, namely Wrough-Cast Bronzes and Bronzes.
• Wrough-Bronzes
Wrough-Bronzes; Bronze or wrought or α is called the Bronze Bronzes containing levels above 8% Tin, made with DAPT formation process in cold rolling or stretched. Bronzes can be resilient during pengerjan process (cold working process), therefore it must be done prior to the formation of annealing process with annealing temperature 7000C. Bronzes have good corrosion resistance properties.

Phosphor Bronzes with levels of up to 0.3% is used as an ingredient in “Wrought Phosphor Bronzes” ie as pagas material, like the springs on the electrical contact as well as a variety of instruments on the coil holder.

• Casting-Bronzes
Casting-Bronzes (α + δ Bronzes) Containing Tin levels between 10 to 18% with the addition of various elements will be obtained complex structures. Casting Bronzes Phosphorus is the most important ingredient as foundry raw material, which contains 10% levels of White Tin (tin) and elemental phosphorus of 0.05%. Bronze is very well used as a bearing material with heavy weights (heavy duty) and Phosphornya levels can be increased up to 0.5% walauypun with little loss of ductility properties.

Bell-metals; material that is formed from the casting to the Tin Bronzes containing up to 20% will thus yielding a sound effect when hit. Speculum metal; Bronze is containing 30% to 40% Lead White, Bronze is very fragile but can be polished so it is often used as a mirror, the light reflection grating and a variety of optical equipment needs as well as the coating material.

Bronzes Leaded Tin-Bronze is an element that contains lead as an element that can lead to materials having properties capable machine (machinability). The content of lead in up to 5% Leaded Bronze and Leaded Bronze which has a lead content of up to 10% can improve the properties of the glide so much used as a bearing. Gunmetal Bronzes are cast with the elemental composition of zinc to give nature the better able cast.

Admiralty Gunmetels composition is made up of 88% Copper and 10% Tin (tin) and 2% Sengan used in the manufacture of ship components, such as Valve and various paralatan-valve steam engine. Leaded Bronzes Gunmetels is the lead element content above 5% were able to improve the properties of Cor (Castingability) and capable machine (Machinability).

Nickel Bronzes Bronze is the addition of a small element into Nickel-Tin Bronzes with the aim to memperbaikai mechanical properties of the bronze, and also it can improve the properties capable cast. Nickel on Bronze Elements will be bound with zinc that will produce hard alloys called “Nickel Gunmetals”.

Nickel alloys with high levels can be illustrated in the diagram the balance due, the process of dissolution would occur if it can be done through the dissolution of the casting process. Heating to 7600C temperature followed by Quenching and followed by heating at temperatures of 3000C per hour will increase tension and violence.

Nickel Bronzes have wear and corrosion resistance properties and can retain its hardness at various temperature changes.

Nickel Bronzes are used as ingredients in the manufacture of various components Valve and feef boiler water. Aluminum Bronzes Copper levels greater given at the end of mixing Copper-Aluminum. From the equilibrium diagram can be indicated that the aluminum levels higher than 9.4% will go into solid solution (Solid Solution) will not increase with the addition of degrees of warming but instead will go down if the temperature exceeds 5650C.

If the levels of aluminum greater than 7.5% and the heating temperature exceeds 5650C will bring up the second phase called Phase Aluminum β and when levels exceed 9.4% by slow cooling, it will form a solid solution (Solid Solution) the phase α + γ . If the alloy is cooled slightly slower as it does pengetokan the mold (Mould) it will slow down the rest of compaction on the β phase will not occur and will result in the structure of the “old”, but if given the addition of a small element of the iron will slow stop with obtaining β phase same result.

In this equilibrium diagram (Figure 1.11) indicates the temperature where the stop phase β depends on the levels of Aluminum and reach a minimum value when the aluminum content of 11.8%.

Part of the equilibrium diagram of the Copper-Aluminum alloy similar to Iron Carbon diagram (FEC), and alloys with high aluminum levels can be in-quenching to produce a similar structure to martensite (see heat treatment) with properties that are very hard and brittle also similar the properties of steel. These alloys can also Temper if necessary nature of the medium.

α-Aluminum Bronzes; Alloys of this type usually contain aluminum levels between 4% and 7% and can be annealed to obtain soft and ductile properties and will harden and stiffen the account after cold working process. Duplex Aluminum Bronzes These alloys contain aluminum levels between 9% to 10% with 2% Iron to inhibit the β phase stops. Alloys in this group are used specifically in the casting sand mold (See Sand Casting) or gravity die-casting and not appropriate for Pressure die casting because it has a small degree of compaction.

Duplex Aluminum Bronzes cast is used as an ingredient for the manufacture of the pump, valve parts, gear and rack. Generally Aluminum Bronzes possess corrosion resistant properties where the presence of alumina film formed section because of the element Aluminum surface and can maintain its mechanical properties at high temperatures.


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