Services

Fundiciones Zabala offers solutions related to the electricity sector, railway, valves, machine tending, lifting, cableway, etc., ensuring the highest levels of satisfaction using primary ingots with their certificates of composition together with the quality standards required in each project. In addition, we strive to adapt the specifications of the commissioned product to the characteristics of the moulds to be used in its manufacture. We do this both by a careful assessment of its future characteristics in its phase of study and design, as through any piece of advice or technical support required in the stages of its machining and assembly.

ALUMINIUM AND ALLOYS CASTING

Aluminium and alloys die casting using gravity moulds in metal and injection moulds, and with different compositions, properties and qualities required for every project and use.

Aluminium is a bluish silver-white malleable ductile light trivalent metallic element that has good electrical and thermal conductivity, high reflectivity, and resistance to oxidation. Its symbol is Al. It is found in different minerals, mostly in bauxite. It is obtained by means of an electrolytic process from the alumina extracted from bauxite.

Aluminium has a density of 2.7 g / cm3 and a melting point of 660 ° C. The tensile strength of pure aluminium castings is about 7 Kg / mm2. The compressive strength is 2.1 kg / mm2. Brinell hardness is 22 Kg / mm2 at ordinary temperature.

The elongation is 30%.

Aluminium is a tough, malleable, ductile metal and a good conductor of heat and electricity. To improve its mechanical properties is alloyed with other metals, mainly silicon (Si), magnesium (Mg), manganese (Mn), copper (Cu) and zinc (Zn), sometimes titanium (Ti) and chromium (Cr) are also added.

Aluminium alloys for casting are standardized and their chemical composition and characteristics can be seen in detail in the Table Aluminium Alloys.
Silicon in the range of 5 to 12% is the most important alloying element because it promotes increased fluidity in molten metals. In smaller amounts, magnesium or copper are added in order to increase the resistance of the castings.

Our supplier of aluminium alloys is ALCOA (Aluminium Company of America), which only provides primary aluminium.

Some alloys can be heat -treated to improve mechanical properties. A heat treatment can be carried out only with the alloys that have as a main alloying agent an item or items whose solid solubility in aluminium increases significantly when temperature rises. This feature enables a more uniform and effective distribution of the alloying elements, resulting in an increase in strength and hardness, as the casting will have a more homogeneous structure.

BRONZE AND COPPER ALLOYS CASTING

Bronze and copper alloys die casting for the production of parts by using gravity moulds in metal and injection moulds, and with different compositions, properties and qualities as required for every project and use.

Copper is a reddish metal and metallic sheen that is characterized as one of the best conductors of electricity (the second after silver). Due to its high electrical conductivity, ductility and malleability, it has become the most used for manufacturing electrical cables and other electronic components. Its symbol is Cu. It is obtained from various minerals such as pyrite, chalcopyrite (S2FeCu), malachite (CuCO3 + Cu (OH) 2), etc. It has a specific gravity of 8.9 g / cm3 when pure and melts at 1083 ° C. The molten copper has a tensile strength of 15.5 to 17.5 kg / mm2 at an elongation of 40% to 50% and a Brinell hardness of 30 to 40 kg / mm2.

Pure copper (over 99%) also called electrolytic copper is rarely used by the foundry industry because it presents many difficulties for casting moulds. The most important copper casting alloys are known under the name of bronze and brass, which have better mechanical properties, but a lower electrical conductivity.

Bronze: Tin and Copper Alloy

Copper alloys with tin are called bronzes and are known since antiquity. The percentage of tin in these alloys is between 2 and 22%. They are yellowish and bronze castings are better quality than brass, but are harder to machine and more expensive. To increase the fluidity of the alloys used in casting, a small amount of zinc is added and to improve machinability, a small percentage of lead is generally added.

The main property of bronze is its high tensile strength and hardness. Its wear resistance is also higher than that of brass, but on the other hand, its machinability is pretty bad.

There are many types of bronzes that also contain other elements such as aluminium, beryllium, chromium, silicon and manganese:

a) Aluminium Bronze
This alloy is composed of copper and aluminium as main metals. Aluminium is present in a proportion of 4 to 12%. It increases the tensile strength and corrosion resistance.

b) Bronze siliceous
It contains 3 to 4.5% silicon. A good fluidity alloy.

c) Bronze for Bells
Generally, it has a content of 20 to 25% tin.
It is a hard alloy with high sonority.

d) Bronze for bearings
It contains from 14 to 18% tin and usually 2% zinc. Babbitt property.
Brass: Copper and Zinc Alloy
It is a binary alloy of copper and zinc, combining these metals in different proportions, which practically limits range from the following:
Copper 50-75%.
Zinc 50 to 25%.
Its density depends on its composition and generally ranges between 8.4 g / cm3 and 8.7 g / cm3. The tensile strength is approximately 30 Kg / mm2 and Brinell hardness between 50 and 60.

The brass does not produce sparks by mechanical impact, an atypical property in alloys. This feature makes the brass important in the manufacture of containers for handling flammable compounds

There are different types of brasses:

a) Yellow Brass (70% copper + 30% Zinc)
It is used to make prints cartridges and boiler accessories.

b) Cast brass (60% copper + 40% Zinc)
High tensile strength of 34 to 39.5 kg / mm2. Brinell hardness 90 to 100 and elongation of 40 to 45%. It is used in valves, radiators, etc.
Alpaca: Copper Alloy + Nickel + Zinc
Alpacas or German silvers are alloys of copper (Cu), nickel (Ni) and zinc (Zn) in a proportion of 50-70% Copper, 13-25% Nickel and 13-25% zinc. Their properties vary continuously depending on the proportion of these elements in its composition. Thus, they go from maximum levels of hardness to minimum levels of conductivity. These alloys have the property to reject marine organisms (antifouling).
Alpaca alloys have good corrosion resistance and good mechanical properties. They are used in the chemical and food industry to make cutlery and silversmith

 ZINC AND ALLOYS CASTING

Zinc and alloys die casting for the production of parts by using gravity moulds in metal and injection mould, and with different compositions, properties and qualities as required for every project and use.

Zinc is a bluish-white metal colour and has a metallic luster. Its symbol is Zn. It is in different minerals being the most important sphalerite (ZnS) and Calamine (ZnCO3). It has a density of 7.1 g / cm3 and melts at 419 ° C. The tensile strength reaches about 15 kg / mm2 at room temperature.

Zinc is used to coat other oxidizable metals such as iron (plating process) and in the construction of ceilings and roofs.

Zinc alloys used in casting are those formed with aluminium (Al), copper (Cu) and magnesium (Mg) because they increase mechanical properties. In die casting, the alloy used is the so called ZAMAK. This alloy was created in the 1920s and its name is an acronym for the alloy elements: zinc, aluminium, magnesium and kupfer (copper). The two ZAMAK alloys most used are ZAMAK-3 and ZAMAK-5 called, which differ in the percentage of containing copper:

ZAMAK-3: Cu = 0.03%, Al = 3.9 to 4.3%, Mg = 0.03 to 0.06%, Zn = rest.
ZAMAK-5: Cu = 0.75 to 1.25%, Al = 3.9 to 4.3%, Mg = 0.03 to 0.06%, Zn = rest.

The ZAMAK-5 alloy has a higher proportion of copper and it is, therefore, stronger and tougher than ZAMAK-3 alloy.

LEAD CASTING

Lead die casting for the production of parts by using gravity moulds in metal and injection mould, and with different compositions, properties and qualities as required for every project and use.

Lead is a heavy metal of a bluish-grey colour with symbol Pb. It is obtained from a mineral called Galena (PbS). It has a density of 11.35 g / cm3 at a temperature of 20 ° C and melts at 327 ° C. It has a tensile strength of only 1.2 to 1.7 Kg / mm2. It is softer than any other heavy metals (Brinell hardness), very malleable and ductile. It is a poor conductor of electricity and heat. It resists the passage of X-rays.

In the foundry industry, its use is limited due to the high specific gravity and low resistance.

The lead-based alloys are called white metals and contain Antimony (Sb) from 10 to 15% and a small percentage of tin (Sn) 5 to 10%.

They are used to manufacture bearings for low-speed and low loads.