In our review we will dwell on the peculiarities and physicochemical parameters of copper-berilya alloy, more known as beryllium bronze. We will tell about the physical and chemical characteristics, as well as the scope of application of this unique composition.
Definition
Beryllium bronze is a copper-berilyan alloy, which includes from 0.5 to 3% beryllium, in some cases it is possible to add other impurities. Berylliye Bronze is different:
- Increased density and fortress in combination with non-magnetic characteristics and a complete absence of an interaction.
- It is capable of subjected to any types of processing - cutting and molding.
- The alloy is used everywhere for the manufacture of instruments, including musical, as well as high-precision devices and bullets for firearms.
- I found my use of copper-beryllium and in aerospace technologies.
Important! Remember that alloys including any amount of beryllium are highly toxic and pose a danger to a person at the stage of production.
Beryllium bronze refers to the group of so-called dispersion hardening compositions . Their distinctive characteristic is the dependence of the solubility of the alloying ingredients from heating.
When performing hardening from a single-phase portion in a solid, an excessive number of atoms of the main alloying component is formed in comparison with the equilibrium state of such a system. The resulting concentrated solid solution is characterized by thermodynamic instability and desire for decay, with an increase in the temperature level, this process is activated. The effect of the seal is explained by the dispersion of the discharge obtained as a result of the decay of substances.
Composition
Chemical formula of beryllium bronze - BRB2, its composition is registered in detail in the current GOST.
The alloy includes such ingredients:
- Copper 97-98%;
- Beryllium 1.9-2.1%;
- Nickel 0.2-0.5%;
- less than 0.5% additives.
Most often used copper-beryllium compositions containing 2% beryllium, as well as copper-beryllium-cobalt alloys, where the percentage presence of beryllium does not exceed 0.8%. The first alloy was called high-alloy beryllium bronze, the second belong to the group of low-alloy marks.
Properties
Beryllium copper has the following physicochemical characteristics.
- Illuminated electric and thermal conductivity. For these parameters, the substance is only slightly inferior to copper.
- Increased elasticity.
- Lack of interactions in mechanical shocks.
- High parameters of corrosive resistance, hardness and time resistance.
All of these characteristics are maximally manifested for all points when beryllium bronze is subjected to a variety of processing methods and hardening. For example, with artificial formation of limit plasticity, such substances are achieved after quenching, which is produced at a temperature of about 770 degrees - in this state, beryllium bronze is exceptional ease.
Type resistance of the substance corresponds to 450 MPa. This parameter increases by 2 times during the plastic deformation of the alloy by 35-50%. As a result, after aging, which is performed immediately upon completion of the hardening process, the mechanical properties of beryllium become extremely high.
Principal for industry, the parameters of copper-beryllium composition are far from limited to those listed. All bronze alloys, the structure of which includes beryllium, is characterized by high heat resistance - products made of them can function without changes in their capabilities at temperatures up to 340 degrees of heat. And when heated to 500 degrees, the mechanical properties and the density of any beryllium bronze become completely identical in their aluminum indicators, as well as tin-phosphoritic compositions with standard operating temperature of about +20 degrees.
This property allows the use of beryllium bronze to produce the highest quality shaped castings.
In most cases, the alloy is made in the form of semi-finished products that have passed the formation stage. Most often it is a thin ribbon, strip or wire.
Beryllium alloys can easily succumb to any mehopling (cutting, soldering and welding). Although there are some restrictions on the listed manipulations. So, any beryllium alloys should be soldered immediately upon completion of their mechanical stripping. At the same time, it is necessary to use silver solder, as well as flux. It is important that the fluorine salts are attended in the flux itself. In recent years, the so-called vacuum soldering has been widely distributed - it is carried out under a thick coating of flux. Thus, the unique quality of the product is ensured.
But the electric arc welding today is practically not used when working with beryllium copper, since it has a significant crystallization thermal interval. Welding suture, as well as point and roller types in the inert media are mastered in a sufficiently full volume. It is worth adding that the specific mechanical characteristics of the material do not allow welding work immediately after thermal processing of bronze - it will certainly be remembered by thinking on the technology of their processing.
Special attention deserves such an indicator as Cooling rate. This indicator must be extremely sharp to prevent the disintegration of the researched solid. That is why when selecting workers hardening media, first of all, it is necessary to proceed from critical speed indicators. These data confirm that during the injection of bronze, the maximum cooling rates should be in the corridor of 500-250 degrees.
Slowing processes at this interval are injected early release of the completion and cause a decrease in the ability to further cure. Critical cooling rate, which allows to achieve an optimal combination of physico-technical characteristics, corresponds to 30-60 g / second for copper with the addition of beryllium. To achieve the desired value, the alloy is usually tempered in water. In order to reduce the parameters of the critical speed, a little cobalt is usually introduced into the alloy. Minimum additions of such metal cause an increase in the resistance of the undercase solution. Similarly, magnesium impurities may affect the resistance of bronze.
Application
Visually beryllium bronze looks like a color alloy, which together It is used in the manufacture of spring elements, wires, rods and some other elements that you want to save the configuration. With frequent deformations and constant overloads, such a wire has an increased electrical conductivity, it is used in low-frequency contacts for the manufacture of electrical connectors.
Strong non-magnetic and without sparkling beryllium copper Found a wide application in the manufacture of pliers, chisel knives, hammers and wrench. Alloy Optimal to perform manipulations with some explosive substances , For example, on grain elevators, drilling rigs or in coal mines.
Beryil-copper alloy often use the manufacture of shock musical instruments to ensure their translational tone and acoustic resonance - usually the material is in demand when creating triangles and tambourines.
The use of alloy is distributed For cryogenic equipment used at the most reduced temperatures. For example, refrigerators. The relevance of using copper beryllium in this field is explained by its fortress and increased thermal conductivity in this temperature range.
Use the composition For the production of gunshot bullets. Although such an application is quite unusual, since the bullet from steel is cheaper and at the same time have quite similar characteristics. Wire made of copper beryllium is released immediately in several forms. It can be figured or flat, rounded or square, various direct layers are available, as well as coils or machines.
Interesting information about Beryllia is presented in the following video.