Which is better, stainless steel or titanium?

How to identify titanium and distinguish it from other metals?

Identification of certain metals is an accurate and simple process only if you have special laboratory equipment, a spectrometer in particular. At home, the task becomes much more complicated. It is especially difficult to distinguish between materials that are similar in color and magnetic properties. However, even in such a situation, there are practical methods to distinguish titanium from other metals. The most interesting for comparison are aluminum and steel, including stainless steel. Here, even experienced craftsmen who regularly work with metals and accept titanium scrap are not always able to clearly identify what exactly they have in their hands.

Titanium and its alloys: properties and scope of application

Identification of certain metals is an accurate and simple process only if you have special laboratory equipment, a spectrometer in particular. At home, the task becomes much more complicated. It is especially difficult to distinguish between materials that are similar in color and magnetic properties.

However, even in such a situation, there are practical methods to distinguish titanium from other metals. The most interesting for comparison are aluminum and steel, including stainless steel.

Here, even experienced craftsmen who regularly work with metals and accept titanium scrap are not always able to clearly identify what exactly they have in their hands.

How to identify real titanium?

In nature, titanium is found in minerals such as titanite, ilmenite or rutile. In its pure form it is a silver-gray light metal with the highest specific strength.

In appearance it is difficult to distinguish it from aluminum or stainless steel. The magnet method will not work here, since magnets also do not attract aluminum or most stainless steels.

To dispel all doubts that you have a sample of real titanium in your hands, you need to conduct one of the tests available to you.

Ordinary wood made stronger than steel or titanium

Wood is a great material for... everything. They make everything from it that you can imagine. The only thing missing is durability. Many types of wood are very strong, but unfortunately are not strong enough to be used more widely. Specialists from the USA have achieved an increase in the strength characteristics of wood through special processing.

After wood is processed using the new method, its strength increases tenfold, it becomes stronger than steel or titanium.

At the same time, wood still remains an environmentally friendly material, an alternative to plastics or metals. “In fact, this is a new class of materials with great potential,” said Li Teng, a scientist at the University of Maryland.

The work of Teng and his colleagues was published on February 7 in the authoritative scientific publication Nature.

Attempts to strengthen the tree and change its characteristics in one way or another have not stopped for decades. Some methods are successful, others not so much. Among the successful ones is the isolation of cellulose microfibers, which makes it possible to create materials that are sufficiently resistant to external influences.

But Teng and his colleagues decided to approach the problem from a different angle. The researchers focused on modifying the porous structure of natural wood.

They initially tried boiling various types of wood, including oak, in a solution of sodium hydroxide and sodium sulfite for seven hours.

This process left the cellulose structure largely intact, but the components surrounding the cellulose were partially gone. One such component is lignin, a polymer that binds cellulose.

The team then placed the wooden block under a press for 24 hours while heating it to 100 degrees Celsius. As a result, wooden planks were formed that were one-fifth the thickness of the previous parameters.

In addition, this material turned out to be three times denser than natural wood and 11.5 times stronger.

Previous attempts to enhance the strength characteristics led to an increase in this parameter by a maximum of 3-4 times.

Scanning the fibers of the new material with an electron microscope showed that squeezing destroys the cellulose tubes, which are compressed and intertwined together. “You get nanofibers placed along the growth axis of the tree, interlocking with each other,” said one of the study participants.

How to distinguish titanium from steel, aluminum

The first pair is non-ferrous and ferrous metals. Most steels have magnetic properties. The exception is alloyed metals of the austenitic class. A striking example is stainless steel with a high nickel content. This grade of steel, like titanium, is paramagnetic. Therefore, the standard option using a magnet is unacceptable here.

There are three reliable ways to determine titanium at home :

• mathematical;
• graphic;
• abrasive;
• galvanic.

The designations are quite conventional; below we will cover each of the options in detail.

Increased corrosion resistance of alloys

Pure mathematics

In this approach, metal identification is done by weight. The disadvantage of the method occurs when only one type of metal is available . To determine in your hands that it cannot be made heavier, you have to resort to mathematical calculations. This is facilitated by significant differences in the density of metals:

• titanium – 4.5;
• iron – 7.8;
• aluminum and duralumin – 2.7.

To use this method for determining titanium in your household, you need to have accurate scales.

Parameter values ​​are given in g/cc. It remains to add that the density of steel depends on the specific grade of metal. However, in absolute terms these differences are insignificant. Therefore, the density of steel can be safely taken as the value of a similar characteristic of iron.

All that remains is to clarify the volume and weight of the part or piece of metal. Further, simple calculations will show whether it is aluminum, steel or the desired metal - titanium. How to determine the volume of a part with a complex shape? The best option here is Archimedes' law. The mass of the ejected liquid, when immersing a metal structure, allows you to determine its volume. The situation is simplified by the density of water, equivalent to 1 kg/cubic dm. Accordingly, each gram of ejected liquid is equal to one cubic centimeter of volume.

Of course, this is a tedious, complex and inaccurate method, but in order to determine titanium at home, it has its place.

This is what titanium metal looks like

How to recognize titanium

Under normal everyday conditions, titanium can be distinguished from other metals using several methods.

Mathematical method

It is not difficult to effectively apply a mathematical approach to titanium recognition when there are several samples of different metals. This method is based on the weight of the product that needs identification.

It should be noted that the density indicator for visually similar metals is significantly different.

The density indicator is:

• titanium 4.5;
• duralumin and aluminum 2.7;
• iron 7.8.

The density of steel is affected by the composition of a particular grade, but this difference is not significant when using this method. Therefore, in practice it is generally accepted that it is equal to the iron indicator. Weighing items of the same volume made from different materials will reveal a titanium sample.

To identify a titanium product in the absence of aluminum or steel samples for comparison, simple mathematical calculations will help, for which it is necessary to determine the volume and weight of the sample under study. For products with complex configurations, Archimedes' law will help determine the volume. The volume of water that the product will push out when immersed in the container will be equal to the volume of this product itself. It is convenient to use a container with a division scale printed on it. Taking into account the density of water, one gram of displaced liquid is equal to a cubic centimeter of volume.

Drawings on glass

This is the most accessible method of how to distinguish titanium at home, but you need to master it and have experience working with titanium. Metal leaves characteristic indelible marks on glass and tiles . It is enough to run the sharpened edge of the metal along one of the specified materials. These are marks, not scratches. Windows of public transport are often painted in a similar way. You can wash titanium graphics on tiles with a solution of hydrofluoric acid; you should handle it with extreme caution.

This method is simple and effective. Titanium, contrary to popular belief, leaves a mark even on dirty glass. So there is no need to degrease its surface. On the contrary, any grade of steel and aluminum can barely scratch the glass. This is an excellent method to identify titanium.

Abrasive wheel

An ideal way to distinguish titanium from stainless steel for owners of a sharpening machine (which, in fact, is not at all necessary). However, almost any abrasive surface will do, even asphalt. The contact of titanium with an abrasive is accompanied by a scattering of rich white sparks. The interaction of steel with an abrasive surface is characterized by a yellow or red tint. There are significantly fewer sparks.

Stainless steel grades are fireproof. Processing of certain brands of stainless steel occurs without sparks at all. This property is used in fire hazardous industries. Only stainless steel tools are allowed there. A similar technique is used in the question of how to distinguish titanium from aluminum. Grinding of the latter on an abrasive wheel also occurs practically without sparks.

This method of determining titanium can be called the most effective - the color of the spark will indeed be different from other metals. In general, the spark test is one of the most popular and correct for determining and recognizing different metals.

Video - how to distinguish titanium from magnesium and aluminum:

What color is titanium?

Titanium; denoted by the symbol Ti) - one of the elements of D. I. Mendeleev’s periodic table of chemical elements, with atomic number 22. The simple substance titanium

- lightweight durable metal of silver-white
color
.

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Other techniques

There are a number of alternative ways to determine titanium in your hands or aluminum, for example. One option is thin shavings. In the case of titanium, it is highly flammable and burns brightly. On the contrary, aluminum shavings melt. When duralumin “metal filings” are placed in an alkaline solution, active evolution of hydrogen is observed.

The next way to distinguish titanium metal from steel and aluminum is thermal conductivity. The numerical values ​​of the parameter W/(m K) for the indicated metals are:

• titanium – 14;
• low carbon steel – 55;
• stainless steel – 16;
• aluminum – 250.

Titanium products are warmer in the hands. Of course, the approach is not characterized by high accuracy, and is generally unsuitable .

High-strength alloys with unstable β-structure

Summary

As you can see, even at home, it is quite possible to distinguish titanium from aluminum and steel. The most practical options are spark and glass . For the first case, any abrasive surface is sufficient, even asphalt or hardened concrete. The bright sparkle of titanium is successfully used by bikers by installing horseshoes made of this metal on their shoes. The mark on the glass is beneficial because the metal is not damaged. A relative disadvantage is that some titanium alloys do not leave a pattern. But for pure metal this is the best option.

Use of abrasives

When processing metal on a grinding machine or during sharp longitudinal friction on the abrasive surface of a grindstone, the contact of titanium is accompanied by a scattering of bright white sparks. If there is no abrasive, you can use a fine file or even plain concrete, although the effect will be less.

Sparks from stainless steel have yellow and red tints. Much less of them fly out, and on concrete and files there will be none at all. Some grades of stainless steel have been developed to be fire resistant. Sparking during processing of such metals is not technologically possible. When aluminum rubs against a forming surface, sparks are not released, but characteristic silvery marks may remain on the surface.

This test for the possibility of spark formation is the most popular and simplest, since the color really differs very much, and their complete absence immediately indicates that this metal is not titanium.

Titanium is the metal of the strong and self-confident

Today we will talk about the main features of this unusual metal, the reasons for its high popularity and how to properly care for it.

History of titanium development

Titanium Ingot

This refractory metal was discovered around 1790, but then scientists had absolutely no idea how it could be useful. At that time, they did not know how to work with it, and due to the difficulty of processing it was nicknamed “Titan,” as the ancient Greeks once called gods with enormous strength and courage.

120 years later, only in 1910, the British began the process of extracting titanium from its ore. This process was constantly improved, and by the mid-1940s the Americans decided to use it in military aviation. The main criteria in this choice were: strength-to-weight ratio, resistance to temperature changes, affordable price, as well as the anti-corrosion properties of the metal.

Use of titanium

Monument to Gagarin in Moscow, made of titanium

Since the 40s of the last century, titanium has been actively used in shipbuilding, aircraft and missiles. It is also used to make bicycle frames, pumps, reactors, prosthetics, fittings, body armor and many other useful things for humans. Titanium has occupied not the last place in watch and jewelry production.

In 1980, a 42-meter monument to Gagarin was erected in Moscow. It became the world's first large pedestal made of this metal. This was not so easy to do; the monument was assembled from 238 cast segments, and the weight of the entire installation was 12 tons.

Titanium in watchmaking

Titanium watch from Porsche Design and IWC (Ocean 2000)

Watchmakers and jewelers turned their attention to titanium not so long ago. It was first used to make watches in 1980. The pioneers were specialists from Porsche Design and IWC. Having combined their forces, the companies released titanium watches that created a real sensation. Soon after this, two more models appeared - Ocean 2000 and Ocean 500 - operating underwater at depths of up to 2000 and 500 meters, respectively.

The main advantages of titanium watches are that they are very light, have a pleasant metallic shine and are somewhat similar in appearance to platinum. True, such watches are inferior to steel products in terms of deformation and susceptibility to scratches.

Titanium in jewelry

Wallace Chan brooch in titanium with rubies, white and yellow diamonds, pink sapphires and tsavorite garnets

In jewelry, titanium was initially used to make wedding rings, piercings, and men's accessories. Its processing is quite complex and costly, requiring certain knowledge and skills from the craftsman, so not every jeweler is involved in creating titanium jewelry. But there are also those who have achieved the highest skill in processing this metal. For example, Chinese jeweler Wallace Chan makes real works of art from titanium in the form of precious flowers, insects or fish.

Titanium has one interesting property: with certain oxidation, heating or mixing with other metals, it can change its color. In its pure form it is a gray metal, but after processing it can acquire green, blue, purple and even red tints. Jewelry houses take advantage of this feature in creating their collections. Among the famous brands that admire titanium are Chopard, Suzanne Syz, Glenn Spiro, Faberge, de Grisogono and others.

How to care for titanium jewelry

Titanium, sapphires, diamonds. Glenn Spiro

Like any other jewelry, titanium products need proper care. There is a misconception that this metal does not scratch. In fact, it may lose its attractive appearance due to aggressive contact with diamond, other metal or sandpaper. At the same time, titanium is not afraid of sea water, sweat and abrasive detergents.

Caring for titanium jewelry is quite simple. They should be stored separately from other jewelry, preferably in a velvet bag or box. When working with other metals or sandpaper, the titanium ring should be removed.

Galvanic reaction test

To perform this test, you will need a DC source with a voltage of about 12 V. This can be a car battery or a converter transformer. Connect the plus wire of the battery to the test sample, and the minus wire to a metal rod, at the end of which cotton wool, gauze or a piece of cotton fabric is wound. Wet cotton wool with a weak solution of hydrochloric acid or regular Coca-Cola.

If it is titanium, then when you touch the metal, its surface will become colored as a result of the formation of an oxide film. The color shade depends on the voltage, the concentration of the acid in the solution and the exposure time. Stainless alloys and aluminum are not susceptible to this reaction.

Galvanic approach

Another sure way to recognize titanium is available right in the garage. The technique is based on coloring this metal through anodization. The simplest design of a “laboratory setup” is a car battery, the plus of which is connected to a titanium plate. A metal rod wrapped in cotton wool soaked in Coca-Cola is connected to the negative of the DC source. The ideal option is any saline solution .

If you run cotton wool over titanium, the metal will become colored within a few seconds. The color obtained during the formation of the oxide film depends on the applied voltage and surface treatment time. However, if the task is how to determine titanium from stainless steel , then the color tone is not important. The main criterion is color change.

Video - how to distinguish titanium from steel using this method:

Specific gravity comparison

Everyone knows that aluminum is the lightest of these three metals, and steel is the heaviest. But how can you determine if you have one sample and nothing to compare with? This can be done by measuring and calculating the density or specific gravity of the material, which is approximately:

• 2.7 g/cm3 for aluminum;
• 4.5 g/cm3 for titanium;
• 7.8 g/cm3 for stainless steel.

This method of determination requires precise scales and a container for immersing the sample in water.

After weighing the metal, it is necessary to determine its volume. The easiest way to do this is to use Archimedes’ law, known from school, by immersing the sample in a liquid. A change in water level will show the desired value.

This is a more complex and lengthy definition option and is therefore used very rarely. But it also produces results and should be considered.

Structural alloys with increased strength

About other properties of titanium

In some cases, metal determination can be done in simple and very original ways:

• titanium shavings ignite and burn quite easily;
• this metal is a good heat insulator and when one edge of the sample is heated, the rest of the sample will be cold;
• low thermal conductivity gives the feeling of a warm object in the hands, unlike cold steel and aluminum.

And lastly, hit the sample with a hammer, as a result there will be no marks on the steel, a small dent will form on the titanium, and the aluminum will suffer the most.

How to identify real titanium?

In nature, titanium is found in minerals such as titanite, ilmenite or rutile. In its pure form it is a silver-gray light metal with the highest specific strength. In appearance it is difficult to distinguish it from aluminum or stainless steel. The magnet method will not work here, since magnets also do not attract aluminum or most stainless steels. To dispel all doubts that you have a sample of real titanium in your hands, you need to conduct one of the tests available to you.

Titanium alloy or metal?

Titanium is a silvery-white non-ferrous metal that is very similar in appearance to steel. The features of this material include a low specific gravity, which is typical for alkali metals. The density of titanium allows it to be placed between iron and aluminum, but its performance characteristics are noticeably higher.

Titanium is four times stronger than copper and iron, twelve times stronger than aluminum, and weighs much less. The yield strength and ductility of pure titanium allow it to be processed at different temperatures. The material can be forged, welded, riveted, rolled.

Low heat and electrical conductivity is maintained even when the operating temperature reaches +500 degrees. Titanium is not capable of magnetization. Even when placed in a magnetic field, the material exhibits paramagnetic properties. It is neither pushed nor attracted.

The material's anti-corrosion resistance is unique and cannot be affected by mechanical stress or aggressive environments. Even in sea water, after ten years, titanium plates will not change their appearance and chemical composition.

Given the difficulty of obtaining titanium in its pure form and its high cost, various titanium alloys are most often used in industry. The element is also used as alloying additives in steel of various grades to increase its strength and heat resistance.

Determination by spark

This is one of the most error-free methods for determining titanium. For it you will need a grinder or a sharpening machine, and if you don’t have one, any abrasive surface, for example, a fine file or asphalt, will do. When aluminum comes into contact with a rotating grinding wheel, the material is ground down with virtually no sparking. The contact of the abrasive and steel is accompanied by a stream of sparks, which range in color from light yellow to dark red.

Tatan, when friction against an abrasive surface or when cutting with a cutting disk, forms a stream of long sparks of bright white color. The fact is that this metal has the property of pyrophoricity, as a result of which small particles of the material formed during grinding or sawing ignite and sparkle in the air. These sparks are much brighter and hotter than those generated when processing steel, so they are white in color and create an increased fire hazard. Titanium powder is even used in pyrotechnics to produce bright pyrotechnic fountains.

Determination by mass

The lightest of these three metals is aluminum, the heaviest is steel. For example, a titanium plate will be one and a half times heavier than an aluminum one and two times lighter than a steel one. If there is nothing to compare the sample with, then you will have to use a mathematical method. The density of the metals in question is known to us and is:

• for titanium – 4.5 g/cm³
• for aluminum – 2.7 g/cm³
• for stainless steel 7.8 g/cm³

This is the mass per unit volume. All that remains is to weigh the product on precise scales and determine its volume. If the product has a complex shape, then it is easier to find out the volume using the Archimedean method. Dip the sample into a container of water and determine the required value by the volume of water displaced. All that remains is to calculate the density by dividing the mass by the volume, and then check whether it corresponds to the density of titanium.

Ductile alloys with medium strength

Identification by mark on glass

This method is the easiest and is based on the ability of titanium to stick to glass during friction, that is, you can draw with it. The same effect is observed when running a sharp edge over a smooth tile, which is due to the high coefficient of friction of pure titanium. If stainless steel scratches a glass surface, then, to your great surprise, this hard metal does not damage the glass, but leaves a characteristic metallic mark on it, which can only be washed off with very strong hydrofluoric acid. Aluminum cannot damage glass or paint on it. It should also be noted that some titanium alloys also do not leave a pattern.

Anodizing test

It is known that as a result of natural oxidation in air, a layer of TiO2 oxide is formed on the surface of titanium. By electrochemical method it is possible to obtain an oxide layer with a coloring effect. To carry out the experiment, you need a 12-volt car battery or several Krona batteries. The titanium sample is connected with a wire to the “+” electrode. Any iron rod wrapped in a piece of cloth soaked in saline solution or any other conductive liquid (vinegar, cola) is connected to the “-” electrode. If you run this cloth over a titanium surface, it will instantly become colored, which will never happen with stainless and aluminum products.

There are a number of other testing methods that allow us to distinguish real titanium from other metals that surround us in everyday life. For example, titanium objects seem warmer upon tactile contact. If you heat one part of the part, the other will remain cold, which indicates its low thermal conductivity. Cutting titanium is much more difficult than other metals. Material particles stick to the blade, making cutting unstable and unsafe. To accurately determine titanium, it is recommended to carry out not one, but several methods.

Advantages/disadvantages

Advantages:
• low density (4500 kg/m 3 ) helps reduce the weight of manufactured products;
• high mechanical strength. It is worth noting that at elevated temperatures (250-500 °C) titanium alloys are superior in strength to high-strength aluminum and magnesium alloys;
• unusually high corrosion resistance due to the ability of Ti to form thin (5-15 μm) continuous films of TiO2 oxide on the surface, firmly associated with the mass of the metal;
• the specific strength (the ratio of strength and density) of the best titanium alloys reaches 30-35 or more, which is almost twice the specific strength of alloy steels.

Flaws:
• high production cost, Ti is much more expensive than iron, aluminum, copper, magnesium;
• active interaction at high temperatures, especially in the liquid state, with all gases that make up the atmosphere, as a result of which Ti and its alloys can only be melted in a vacuum or in an environment of inert gases;
• difficulties in involving titanium waste into production;
• poor antifriction properties due to Ti adhesion to many materials; titanium paired with titanium cannot work on friction at all;
• high susceptibility of Ti and many of its alloys to hydrogen embrittlement and salt corrosion;
• poor machinability, similar to the machinability of austenitic stainless steels;
• high chemical activity, tendency to grain growth at high temperatures and phase transformations during the welding cycle cause difficulties in welding titanium.