Density of mercury and its properties. Density of mercury and its properties Density of industrial aluminum alloys

Today, many complex structures and devices have been developed that use metals and their alloys with different properties. To use the most suitable alloy in a particular structure, designers select it in accordance with the requirements of strength, fluidity, elasticity, etc., as well as the stability of these characteristics in the required temperature range. Next, the required amount of metal that is required for the production of products from it is calculated. To do this, you need to make a calculation based on its specific gravity. This value is constant - this is one of the main characteristics of metals and alloys, practically coinciding with density. It is easy to calculate: you need to divide the weight (P) of a piece of solid metal by its volume (V). The resulting value is denoted γ, and it is measured in Newtons per cubic meter.

Specific gravity formula:

Based on the fact that weight is mass multiplied by the acceleration of gravity, we get the following:

Now about the units of measurement of specific gravity. The above Newtons per cubic meter are in the SI system. If the GHS metric system is used, then this value is measured in dynes per cubic centimeter. To indicate specific gravity in the MKSS system, the following unit is used: kilogram-force per cubic meter. Sometimes it is acceptable to use gram-force per cubic centimeter - this unit lies outside all metric systems. The basic relationships are as follows:

1 dyne/cm3 = 1.02 kg/m3 = 10 n/m3.

The higher the specific gravity value, the heavier the metal. For light aluminum this value is quite small - in SI units it is equal to 2.69808 g/cm3 (for example, for steel it is equal to 7.9 g/cm3). Aluminum, as well as its alloys, is in high demand today, and its production is constantly growing. After all, this is one of the few metals needed for industry, the supply of which is in the earth’s crust. Knowing the specific gravity of aluminum, you can calculate any product made from it. For this, there is a convenient metal calculator, or you can make the calculation manually by taking the specific gravity of the desired aluminum alloy from the table below.

However, it is important to take into account that this is the theoretical weight of rolled products, since the content of additives in the alloy is not strictly defined and can fluctuate within small limits, then the weight of rolled products of the same length, but from different manufacturers or batches may differ, of course this difference is small, but it is there.

Here are some calculation examples:

Example 1. Calculate the weight of A97 aluminum wire with a diameter of 4 mm and a length of 2100 meters.

Let us determine the cross-sectional area of ​​the circle S=πR 2 means S=3.1415 2 2 =12.56 cm 2

Let's determine the weight of rolled products knowing that the specific gravity of grade A97 = 2.71 g/cm 3

M=12.56·2.71·2100=71478.96 grams = 71.47 kg

Total wire weight 71.47 kg

Example 2. Calculate the weight of a circle made of AL8 aluminum with a diameter of 60 mm and a length of 150 cm in the amount of 24 pieces.

Let's determine the cross-sectional area of ​​the circle S=πR 2 means S=3.1415 3 2 =28.26 cm 2

Let's determine the weight of the rolled product knowing that the specific gravity of the AL8 grade = 2.55 g/cm 3

There is no such person who has not seen yellow metal in his entire life. There are several minerals found in nature that are similar in appearance to the yellow metal. But as they say: “all that glitters is not gold.” In order not to confuse the precious metal with other materials, you need to know the density of gold.

Density of noble metal

Molecular structure of gold.

One of the important characteristics of a precious metal is its density. The density of gold is measured in kg m3.

Specific gravity is a very significant characteristic for gold. This is usually not taken into account, since jewelry: rings, earrings, pendants have very little weight. But if you hold a kilogram ingot of real yellow metal in your hands, you can see that it is very heavy. The significant density of gold makes it easier to mine. Thus, washing at sluices ensures a high level of gold recovery from washed rocks.

The density of gold is 19.3 grams per cubic centimeter.

This means that if you take a certain volume of precious metal, it will weigh almost 20 times more than the same volume of plain water. A two-liter plastic bottle of golden sand weighs about 32 kg. From 500 grams of precious metal you can lay out a cube with a side of 18.85 mm.

Table of density of gold of various samples and colors.

The density of the original gold is several units lower than that of the already purified metal and can vary from 18 to 18.5 grams per cubic centimeter.

583 gold is less dense, as this alloy consists of different metals.

At home, you can determine the density of gold yourself. To do this, you need to weigh the precious metal product on ordinary scales, in which the division value must be at least 1 gram. After this, a container with a volume marking must be filled with liquid, in this case water, into which the decoration should be lowered. Care must be taken to ensure that the liquid does not overflow.

After this, we measure how much the volume of liquid has changed after lowering the gold item into the container. Using a special formula, known from school, we calculate density: mass divided by volume.

It must be remembered that a precious metal product is not made of pure gold, so it is necessary to make an adjustment for the density of the alloy sample.

How to distinguish real yellow metal from a fake

At the moment, there is a very large percentage of counterfeit gold on both the Russian and foreign markets. There is a huge risk of purchasing gold jewelry containing up to 5% of the precious metal or without it at all. Basic rules when buying gold will help you avoid feeling deceived.

First, you should take a good look at the product. There must be a sample on it. Moreover, it should not consist of crooked numbers or blurry marks. Otherwise, this is the first sign of a counterfeit.

A sample of a unified state hallmark for gold products.

The next sign of a fake is the reverse side of the precious metal jewelry. It must be as well executed as the front side, otherwise it is a low-quality product. It is also possible to determine the quality of a product using a characteristic such as gold density, but it is impossible to conduct such an experiment in a store.

There is also a way to determine it, called a strength test. True, it is not always possible to scratch a gold item in front of the seller, so this method cannot be implemented.

Iodine test.

The following chemical methods can serve as good ways to determine the quality of a product. You can drop a little iodine onto the yellow metal jewelry. If the speck is dark in color, then we can speak with confidence about the quality of the product being offered. Table vinegar can also help. If, after three minutes spent in it, the precious metal has darkened, then you can safely take the product to a landfill.

Gold chloride can be a great help in determining quality. From the chemistry course, it became known not only the density of gold, but also the fact that it cannot enter into any chemical reactions. Therefore, if after applying gold chloride to a precious metal it begins to deteriorate, then this is a real fake and should belong in the trash.

One of the best ways to protect yourself from purchasing counterfeit goods is to purchase precious metal products in well-known specialized stores.

In this case, there is a high probability of purchasing a truly high-quality product. Even though their prices are a little higher than in various shops and markets, the quality is worth it. Otherwise, you can purchase a counterfeit product and very much regret the money saved.

Gemini of gold

There are several metals found in nature that have the same density as gold. These are uranium, which is radioactive, and tungsten. It is cheaper than the yellow metal, but the density of tungsten and gold is almost the same, the difference is three tenths. What distinguishes tungsten from gold is that it has a different color and is much harder than the yellow metal. Pure gold is very soft and can be easily scratched with a fingernail.

A fake gold bar filled with tungsten on the inside.

The fact that the density of elements such as tungsten and gold is the same is very attractive to counterfeiters. They replace gold bars with tungsten of similar density and weight, and cover the top with a thin layer of precious metal. At the same time, the high cost of the yellow metal makes tungsten more popular among young people. Tungsten products are much cheaper and more scratch resistant.

Lead Density

The purer the gold, the less hard it is, so in the past the yellow metal was bitten to test. This method is unreliable. The jewelry can be made of lead, covered with a very thin layer of gold. Lead also has a soft structure. You can try to scratch the jewelry from the wrong side, and underneath a very thin layer of precious metal you may find base metal.

The density of the element of the periodic table - lead and its brother - gold is different. The density of lead is much less than gold and is 11.34 grams per cubic centimeter. Thus, if we take the yellow metal and lead of the same volume, then the mass of gold will be much greater than that of lead.

White gold is an alloy of yellow precious metal with platinum or other metals that give it a white, or rather matte silver, color. There is an opinion in everyday life that “white gold” is one of the names for platinum, but this is not so. This type of gold costs a little more than usual. In appearance, the white metal is similar to silver, which is much cheaper. The density of such elements of the periodic table as gold and silver is different. How to distinguish white gold from silver? These precious metals have different densities.

Silver is the least dense material of all those discussed in the article.

The density of gold is greater than that of silver. Its density is 10.49 grams per cubic centimeter. Silver is much softer than white metal. Therefore, if you run a silver item across a white sheet, a mark will remain. If you do the same with white precious metal, there will be no trace.

All metals have certain physical and mechanical properties, which, in fact, determine their specific gravity. To determine how suitable a particular alloy of ferrous or stainless steel is for production, the specific gravity of rolled metal is calculated. All metal products that have the same volume, but are made from different metals, for example, iron, brass or aluminum, have different mass, which is directly dependent on its volume. In other words, the ratio of the volume of the alloy to its mass - specific density (kg/m3) is a constant value that will be characteristic of a given substance. The density of the alloy is calculated using a special formula and is directly related to the calculation of the specific gravity of the metal.

The specific gravity of a metal is the ratio of the weight of a homogeneous body of this substance to the volume of the metal, i.e. this is density, in reference books it is measured in kg/m3 or g/cm3. From here you can calculate the formula for finding out the weight of a metal. To find this you need to multiply the reference density value by the volume.

The table shows the densities of non-ferrous metals and ferrous iron. The table is divided into groups of metals and alloys, where under each name the grade according to GOST and the corresponding density in g/cm3 are indicated, depending on the melting point. To determine the physical value of specific density in kg/m3, you need to multiply the tabulated value in g/cm3 by 1000. For example, this way you can find out what the density of iron is - 7850 kg/m3.

The most typical ferrous metal is iron. The density value - 7.85 g/cm3 can be considered the specific gravity of iron-based ferrous metal. Ferrous metals in the table include iron, manganese, titanium, nickel, chromium, vanadium, tungsten, molybdenum, and ferrous alloys based on them, for example, stainless steel (density 7.7-8.0 g/cm3), black steel ( density 7.85 g/cm3) cast iron (density 7.0-7.3 g/cm3) is mainly used. The remaining metals are considered non-ferrous, as well as alloys based on them. Non-ferrous metals in the table include the following types:

− light - magnesium, aluminum;

− noble metals (precious) - platinum, gold, silver and semi-precious copper;

− low-melting metals – zinc, tin, lead.

Specific gravity of non-ferrous metals

Table. Specific gravity of metals, properties, metal designations, melting point
Name of metal, designation	Atomic weight	Melting point, °C	Specific gravity, g/cc
Zinc Zn (Zinc)	65,37	419,5	7,13
Aluminum Al	26,9815	659	2,69808
Lead Pb (Lead)	207,19	327,4	11,337
Tin Sn (Tin)	118,69	231,9	7,29
Copper Cu (Copper)	63,54	1083	8,96
Titanium Ti (Titanium)	47,90	1668	4,505
Nickel Ni (Nickel)	58,71	1455	8,91
Magnesium Mg (Magnesium)	24	650	1,74
Vanadium V	6	1900	6,11
Tungsten W (Wolframium)	184	3422	19,3
Chrome Cr (Chromium)	51,996	1765	7,19
Molybdenum Mo (Molybdaenum)	92	2622	10,22
Silver Ag (Argentum)	107,9	1000	10,5
Tantalum Ta (Tantal)	180	3269	16,65
Iron Fe (Iron)	55,85	1535	7,85
Gold Au (Aurum)	197	1095	19,32
Platinum Pt (Platina)	194,8	1760	21,45

When rolling non-ferrous metal blanks, it is also necessary to know exactly their chemical composition, since their physical properties depend on it.
For example, if aluminum contains impurities (even within 1%) of silicon or iron, then the plastic characteristics of such a metal will be much worse.
Another requirement for hot rolling of non-ferrous metals is extremely precise temperature control of the metal. For example, zinc requires a temperature of strictly 180 degrees when rolling - if it is slightly higher or slightly lower, the capricious metal will sharply lose its ductility.
Copper is more “loyal” to temperature (it can be rolled at 850 – 900 degrees), but it requires that the melting furnace must have an oxidizing (high oxygen content) atmosphere - otherwise it becomes brittle.

Table of specific gravity of metal alloys

The specific gravity of metals is most often determined in laboratory conditions, but in their pure form they are very rarely used in construction. Alloys of non-ferrous metals and alloys of ferrous metals, which according to their specific gravity are divided into light and heavy, are much more often used.

Light alloys are actively used by modern industry due to their high strength and good high-temperature mechanical properties. The main metals of such alloys are titanium, aluminum, magnesium and beryllium. But alloys based on magnesium and aluminum cannot be used in aggressive environments and at high temperatures.

Heavy alloys are based on copper, tin, zinc, and lead. Among the heavy alloys, bronze (an alloy of copper with aluminum, an alloy of copper with tin, manganese or iron) and brass (an alloy of zinc and copper) are used in many industries. Architectural parts and sanitary fittings are produced from these grades of alloys.

The reference table below shows the main quality characteristics and specific gravity of the most common metal alloys. The list provides data on the density of basic metal alloys at an ambient temperature of 20°C.

List of metal alloys	Density of alloys (kg/m3)
Admiralty Brass (30% zinc, and 1% tin)	8525
Aluminum bronze - Aluminum Bronze (3-10% aluminum)	7700 - 8700
Babbitt - Antifriction metal	9130 -10600
Beryllium bronze (beryllium copper) - Beryllium Copper	8100 - 8250
Delta metal - Delta metal	8600
Yellow brass - Yellow Brass	8470
Phosphorous bronze - Bronze - phosphorous	8780 - 8920
Common bronzes - Bronze (8-14% Sn)	7400 - 8900
Inconel - Inconel	8497
Incoloy	8027
Wrought Iron	7750
Red brass (low zinc) - Red Brass	8746
Brass, casting - Brass - casting	8400 - 8700
Brass , rental - Brass - rolled and drawn	8430 - 8730
Lungs alloys aluminum - Light alloy based on Al	2560 - 2800
Lungs alloys magnesium - Light alloy based on Mg	1760 - 1870
Manganese Bronze	8359
Cupronickel - Cupronickel	8940
Monel	8360 - 8840
Stainless Steel	7480 - 8000
Nickel silver - Nickel silver	8400 - 8900
Solder 50% tin/50% lead - Solder 50/50 Sn Pb	8885
Light anti-friction alloy for casting bearings = matte containing 72-78% Cu - White metal	7100
Lead bronze, Bronze - lead	7700 - 8700
Carbon steel - Steel	7850
Hastelloy - Hastelloy	9245
Cast iron - Cast iron	6800 - 7800
Electrum (gold-silver alloy, 20% Au) - Electrum	8400 - 8900

The density of metals and alloys presented in the table will help you calculate the weight of the product. The method for calculating the mass of a part is to calculate its volume, which is then multiplied by the density of the material from which it is made. Density is the mass of one cubic centimeter or cubic meter of a metal or alloy. Mass values ​​calculated on a calculator using formulas may differ from real ones by several percent. This is not because the formulas are not accurate, but because in life everything is a little more complicated than in mathematics: right angles are not quite right, circles and spheres are not ideal, deformation of the workpiece during bending, embossing and hammering leads to unevenness of its thickness , and you can list a bunch more deviations from the ideal. The final blow to our desire for precision comes from grinding and polishing, which lead to unpredictable weight loss in the product. Therefore, the obtained values ​​should be treated as indicative.

Unit

Aluminum Density and any other material is a physical quantity that determines the ratio of the mass of the material to the occupied volume.

• The unit of measurement for density in the SI system is kg/m3.
• For the density of aluminum, a more descriptive dimension g/cm 3 is often used.

Density of aluminum in kg/m3a thousand times more than in g/s m 3.

Specific gravity

To estimate the amount of material per unit volume, such a non-systemic, but more visual unit of measurement as “specific gravity” is often used. Unlike density, specific gravity is not an absolute unit of measurement. The fact is that it depends on the magnitude of gravitational acceleration g, which varies depending on the location on Earth.

Dependence of density on temperature

The density of the material depends on temperature. It usually decreases with increasing temperature. On the other hand, specific volume—volume per unit mass—increases with increasing temperature. This phenomenon is called thermal expansion. It is usually expressed as a coefficient of thermal expansion, which gives the change in length per degree of temperature, for example mm/mm/ºC. Change in length is easier to measure and apply than change in volume.

Specific volume

The specific volume of a material is the reciprocal of density. It shows the volume of a unit of mass and has the dimension m 3 / kg. Based on the specific volume of the material, it is convenient to observe the change in the density of materials during heating and cooling.

The figure below shows the change in specific volume of various materials (pure metal, alloy and amorphous material) with increasing temperature. The flat sections of the graphs represent temperature expansion for all types of materials in solid and liquid states. When a pure metal is melted, there is a jump in the increase in specific volume (a decrease in density); when an alloy is melted, it rapidly increases as it melts in the temperature range. Amorphous materials, when melted (at the glass transition temperature), increase their coefficient of thermal expansion.

Aluminum Density

Theoretical density of aluminum

The density of a chemical element is determined by its atomic number and other factors such as atomic radius and the way the atoms are packed. T The theoretical density of aluminum at room temperature (20 °C) based on the parameters of its atomic lattice is:

• 2698.72 kg/m3.

Density of aluminum: solid and liquid

A graph of aluminum density versus temperature is shown in the figure below:

• As the temperature increases, the density of aluminum decreases.
• When aluminum transitions from a solid to a liquid state, its density decreases abruptly from 2.55 to 2.34 g/cm 3 .

The density of aluminum in the liquid state - molten 99.996% - at various temperatures is presented in the table.

Aluminum alloys

Effect of doping

Differences in the density of different aluminum alloys are due to the fact that they contain different alloying elements and in different quantities. On the other hand, some alloying elements are lighter than aluminum, others are heavier.

Alloying elements lighter than aluminum:

• silicon (2.33 g/cm³),
• magnesium (1.74 g/cm³),
• lithium (0.533 g/cm³).

Alloying elements heavier than aluminum:

• iron (7.87 g/cm³),
• manganese (7.40 g/cm³),
• copper (8.96 g/cm³),
• zinc (7.13 g/cm³).

The effect of alloying elements on the density of aluminum alloys is demonstrated by the graph in the figure below.

Density of industrial aluminum alloys

The densities of aluminum and aluminum alloys that are used in industry are presented in the table below for the annealed state (O). To a certain extent, it depends on the state of the alloy, especially for heat-hardening aluminum alloys.

Aluminum-lithium alloys

The famous aluminum-lithium alloys have the lowest density.

• Lithium is the lightest metal element.
• The density of lithium at room temperature is 0.533 g/cm³ - this metal can float in water!
• Every 1% lithium in aluminum reduces its density by 3%
• Every 1% lithium increases the elastic modulus of aluminum by 6%. This is very important for aircraft construction and space technology.

Popular industrial aluminum-lithium alloys are 2090, 2091 and 8090:

• Alloy 2090 has a nominal lithium content of 1.3% and a nominal density of 2.59 g/cm3.
• Alloy 2091 has a nominal lithium content of 2.2% and a nominal density of 2.58 g/cm3.
• Alloy 8090 with a lithium content of 2.0% has a density of 2.55 g/cm 3 .

Density of metals

Density of aluminum compared to the density of other light metals:

• aluminum: 2.70 g/cm 3
• titanium: 4.51 g/cm 3
• magnesium: 1.74 g/cm3
• beryllium: 1.85 g/cm 3

Sources:
1. Aluminum and Aluminum Alloys, ASM International, 1993.
2. FUNDAMENTALS OF MODERN MANUFACTURING – Materials, Processes, and Systems / Mikell P. Groover – JOHN WILEY & SONS, INC., 2010