Bronze

Bronze — based alloy of copper and tin, alloying components where there may be beryllium, aluminum and other elements, most commonly phosphorus, aluminum, zinc and lead. But bronze can’t be an alloy of copper with zinc (brass then it turns out) or alloys of copper and Nickel.

Relevance

The best-known tin bronze — an alloy of copper and tin (copper usedonmost). This is one of the first metals exploited by man. People know the composition of the ancient Bronze age. For a long time, the bronze remained a strategic metal (until the nineteenth century guns were cast from bronze). This metal is remarkable for its qualities — such as hardness, strength, high workability. With the discovery of bronze before the man opened up tremendous prospects. See the prices for non-ferrous metals and buy bronze you can on our website.

Properties

Tin bronze is treated badly pressure, bad cut, bend. It is the casting metal and their casting quality is not inferior to other metals. It is characterized by low shrinkage of 1−2%, the shrinkage of brass and cast iron = 1.6%, and steel — more than 3%. Therefore, bronze has been used successfully to create complex art of casting. It has high corrosion resistance and antifriction properties. Used in the chemical industry for creating valve and as an antifriction material in moving parts.

Brand bronze

Tin bronze can be alloyed with zinc, aluminum, Nickel, phosphorus, lead, arsenic or other metals. Adding zinc (no more than 11%) does not change the characteristics of bronze, but much cheaper.

The percentage BROF2−0.25 GOST 5017−2006

Alloy	Fe	Ni	As	Cu	Pb	Zn	R	Sn	Impurities
BROF2−0.25	≤0.05	≤0,2	---	96,7−98,98	≤0.3 mm	≤0.3	Of 0.02−0.3	1−2,5	≤0.3 mm

Bronze with the addition of zinc has the name «Admiralty bronze» and has a very high resistance to corrosion in sea water. Lead and phosphorus improve the sliding properties of bronze, the duration of operation of mobile nodes. Aluminum bronze is light and high specific strength.

The percentage Brazhmc10−3-1,5 GOST 18 175−78

Si	Fe	Mn	Al	Cu	Pb	Zn	R	Sn	Impurities
≤0.1	2−4	1−2	9−11	82,3−88	≤0,03	≤0.5	≤0.01	≤0.1	≤0,7

It is demanded in transport engineering. Its high conductivity is important in electrical engineering. Details of beryllium bronze spark when striking, they are used in a potentially explosive environment.

The percentage Brb2 GOST 18 175−78

Alloy	Fe	Si	Al	Cu	Pb	Zn	Be	Ni	Impurities
Brb2	≤0.15	≤0,15	≤0,15	96,9−98	≤0,005	---	1,8−2,1	0,2−0,5	≤0,6

A number of copper alloys are not bronzes. The most famous of them — brass (alloy of Cu+Zn) and Constantan (Cu+Ni).

Supply

Supply a certified non-ferrous metal and bronze alloys at the best prices. In the specifications reflected data on the percentage composition and mechanical properties of products. We can easily buy in bulk any semi-finished products for large-scale production. Provide favorable conditions for retail customers. Our company has a high level of service and efficiency of service.

Buy at best price

All products from rare and non-ferrous metals, implemented by the company «Electrocentury-steel» comply with GOST and international quality standards. To purchase a bronze in the shortest possible time from warehouses located on the territory of Russia and Ukraine. High quality, affordable prices and a wide range of products define the face of our company. Becoming our regular customer, You will be able to rely on the system of discount discount. Cooperation with us will help You to implement any engineering plans. Waiting for Your orders on the website evek.org.

Bronze

The bronzes are alloys of copper containing more than 2.5% (by mass) of alloying components.

In bronze, the zinc content shall not exceed the amount of content of other alloying elements, otherwise the alloy will refer to the brass.

The name of bronze is given on the main alloying element (aluminum, tin, etc.), although in some cases two or three (tin-phosphorus, tin-zinc, tin-zinc-svintsoviy, etc.).

Without tin bronze

A consolidated list of the domestic standard bronze without tin pressure treated, and their foreign alloys-analogues are given in table. 1.

Consolidated list letter standard bronze without tin pressure treated and their foreign alloys-analogues

Low-alloy bronze:

Grade of bronze	The analogue of the US	Analog Germany	Analog Japan	Note
Brsr0,1	-	CuAg0,1 (2.1203)	-	silver (Ag)
-	-	CuAg0,1P (2.1191)	-	silver (Ag)
Tellurium bronze	С14500	CuTeP (2.1546)	-	tellurium (Te)
-	C19600	-	-	ferrous (Fe)
-	C19200	-	-	ferrous (Fe)
-	C19500	-	-	ferrous (Fe)
-	C19400	CuFe2P (2.1310)	-	ferrous (Fe)
-	-	-	C1401	other
Brmg0,3	-	CuMg0,4 (2.1322)	-	other
-	C14200	-	-	other
-	C14700	CuSP (2.1498)	-	other
-	-	CuZn0,5 (2.0205)	-	other
-	-	CuMg0,4 (2.1322)	-	other
-	-	CuMg0,7 (2.1323)	-	other
-	C15100	CuZr (2.1580)	-	other
Brh1	-	-	-	other
-	C18400	CuCrZr (2.1293)	-	other
Brkd1	-	-	-	other
-	-	CuPbIp (2.1160)	-	other

Aluminum bronze:

Grade of bronze	The analogue of the US	Analog Germany	Analog Japan	Note
Bra5	C60800	CuA15As (2.0918)	-	Al-Cu
Bra7	-	CuA18 (2.0920)	-	Al-Cu
-	C61400	CuAl8Fe3 (2.0932)	C6140	Al-Fe-Cu
-	C61300	-	-	Al-Fe-Cu
Brazh9−4	C62300	-	-	Al-Fe-Cu
The same	C61900	-	-	Al-Fe-Cu
-	C62400	-	-	Al-Fe-Cu
Bramc9−2	-	CuA19Mn2 (2.0960)	-	Al-Mn-Cu
Bramc10−2	-	-	-	Al-Mn-Cu
-	С64200	-	-	Al-Si-Cu
-	С64210	-	-	Al-Si-Cu
Brazhmc10−3-1b5	-	CuA10Fe3Mn2 (2.0936)	-	Al-Fe-Mn-Cu
Brazhn10−4-4	C63000	CuA110Ni5Fe4 (2.0966)	-	Al-Fe-Ni-Cu
-	-	CuA111Ni6Fe5 (2.0978)	-	Al-Fe-Ni-Cu
-	-	CuA19Ni3Fe2 (2.0971)	-	Al-Fe-Mn-Ni-Cu
-	-	-	C6161	Al-Fe-Mn-Ni-Cu
-	-	-	C6280	Al-Fe-Mn-Ni-Cu
Brazhnmc9−4-4−1	C63200	-	C6301	Al-Fe-Mn-Ni-Cu
-	C63800	-	-	Al-Si-Co-Cu and Al-Si-Ni-Cu
-	C64400	-	-	Al-Si-Co-Cu and Al-Si-Ni-Cu

Beryllium bronze:

Grade of bronze	The analogue of the US	Analog Germany	Analog Japan
-	C17410	-	-
-	C17510	CuNi2Be (2.0850)	-
-	C17500	CuCo2Be (2.1285)	-
-	C17000	CuBe1,7 (2.1245)	C1700
Brb2	C17200	CuBe2 (2.1447)	C1720
-	-	CuBe2Pb (2.1248)	-
БрБЕТ1,9	-	-	-
Brbnt1,9mg	-	-	-

Siliceous bronze

Grade of bronze	The analogue of the US	Analog Germany	Analog Japan
-	-	CuNi1,5Si (2.0853)	-
-	C64700	-	-
Brkn1−1	-	CuNi2Si (2.0855)	-
-	-	CuNi3Si (2.0857)	-
-	C70250	-	-
-	C65100	-	-
Brkmc3−1	-	-	-
The same	C65500	-	-

Manganese bronze

Grade of bronze	The analogue of the US	Analog Germany	Analog Japan
Brmc5	-	-	-

Tellurium bronze in GOST 18175 has no special designation

Table. 2. The chemical composition of tin-bronze (GOST 18175−78) (mass fraction, %)

Mark	Limit content. elements	Cu	Ag	Al	Be	Cd	Cr	Fe	Mg	Mn	Ni	P	Pb	Si	Sn	Te	Ti	Zn	The amount of other elements
Bra5	min.	.	-	4,0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Bra5	max.	-	-	6,0	-	-	-	0,5	-	0,5	-	0,01	0,03	0,1	0,1	-	-	0,5	1,1
Bra7	min.	.	-	6,0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Bra7	max.	-	-	8,0	-	-	-	0,5	-	0,5	-	0,01	0,03	0,1	0,1	-	-	0,5	1,1
Bramc9−2	min.	.	-	8,0	-	-	-	_	-	1,5	-	-	-	-	-	-	-	-	-
Bramc9−2	max.	-	-	10,0	-	-	-	0,5	-	2,5	-	0,01	0,03	0,1	0,1	-	-	1,0	1,5
Bramc10−2	min.	.	-	9,0	_	-	-	_	-	1,5	-	-	-	-	-	-	-	-	-
Bramc10−2	max.	-	-	11,0	-	-	-	0,5	-	2,5	-	0,01	0,03	0,1	0,1	-	-	1,0	1,7
Brazh9−4	min.	.	-	8,0	-	-	-	2	-	-	-	-	-	-	-	-	-	-	-
Brazh9−4	max.		-	10,0	-	-	-	4	-	0,5	-	0,01	0,01	0,1	0,1	-	-	1	1,7
Brazhmc10−3-1,5	min.	.	-	9,0	-	-	-	2	-	1,0	-	-	-	-	-	-	-	-	-
Brazhmc10−3-1,5	max.		-	11,0	-	-	-	4	-	2,0	-	0,01	0,03	0,1	0,1	-	-	0,5	0,7
Brazhn10−4-4	min.	.	-	9,5	-	-	-	3,5	-	-	3,5	-	-	-	-	-	-	-	-
Brazhn10−4-4	max.	-	-	11,0	-	-	-	5,5	-	0,3	5,5	0,01	0,02	0,1	0,1	-	-	0,3	0,6
Brazhnmc9−4-4−1	min.	.	-	8,8	-	-	-	4	-	0,5	4,0	-	-	-	-	-	-	-	-
Brazhnmc9−4-4−1	max.	-	-	11,0	-	-	-	5	-	1,2	5,0	0,01	0,02	0,1	0,1	-	-	0,5	0,7
Brb2	min.	.	-	-	1,8	-	-	-	-	-	0,2	-	-	-	-	-	-	-	-
Brb2	max.	-	-	0,2	2,1	-	-	0,15	-	-	0,5	-	0,05	0,15	-	-	-	-	0,5
Brbnt1,9	min.	.	-	-	1,85	-	-		-	-	0,2	-	-	-	-	-	0,10	-	-
Brbnt1,9	max.	-	-	0,2	2,1	-	-	0,15	-	-	0,4	-	0,05	0,15	-	-	0,25	-	0,5
Brbnt1,9mg	min.	.	-	-	1,85	-	-	-	0,07	-	0,2	-	-	-	-	-	0,10	-	-
Brbnt1,9mg	max.	-	-	0,2	2,1	-	-	0,15	0,13	-	0,4	-	0,05	0,15	-	-	0,25	-	0,5

Table. 3. Characteristic properties and kinds of semi-finished products of tin bronze

Grade of bronze	Typical properties	The types of semi-finished products
Bramc9−2	high resistance to alternating loads	strips, strips, bars, wire, forgings
Brazh9−4	high mechanical properties, good anti-friction properties, corrosion resistant	rods, tubes, forgings
Brazhmc10−3-1,5	badly deformed in the cold state, is deformed in a hot condition, high strength at elevated temperatures, corrosion-resistant, high erosion and cavitation resistance	rods, tubes, wire, forgings
Brazhn10−4-4	badly deformed in the cold state, is deformed in a hot condition, high strength at elevated temperatures, corrosion-resistant, high erosion and cavitation resistance	rods, tubes, forgings
Brb2, Brbnt1,9	high strength and wear resistance, high spring properties, good anti-friction properties, the average conductivity and thermal conductivity, good deformability in the hardened state	strips, ribbons, rods, tubes, wire
Brkmc3−1	corrosion resistant, weldable, high-temperature, high compression resistance	sheets, strips, ribbons, rods, wire
Brkn1−3	high mechanical and technological properties, corrosion resistant, good sliding properties	sheets, strips, ribbons, rods, wire

Figure 1. State diagram of the system (equilibrium)

The diagram shows that the maximum solubility of aluminium in copper in the solid state is 9.4% (by weight). With increasing temperature from 565 to 1037 °C the solubility of aluminum in copper is reduced and reaches 7.5%.

To stable phases of Cu-Al are α, β, γ2 and α2 phase.

The α phase is the primary solid solution, isomorphous, with the elementary face-centered cubic crystal lattice. By slow cooling the alloy to a temperature of 400 °C, the α-phase forms a short-range order, which leads to a marked decrease in its electrical resistance, which continues at a temperature below 200 °C as a result of elimination of defects of the package.

The phase of the β — solid solution formed on the basis of the stoichiometric composition Cu3Аl directly from the melt at a temperature 1036−1079°C, with the elementary centered cubic crystal lattice. Phase β of a plastic, electrically conductive and stable at temperatures above 565 °C. During the rapid cooling of the alloy (at a speed of >2°C/min), she experiences a dramatic transformation type martensitic, forming the intermediate phase (Fig. 1). By slow cooling (2°C/min) of β-phase decomposes into eutectoid α+γ2 γ2 formation of coarse-grained phase that is released in the form of continuous chains, giving the alloy fragility. Phase γ2 (Cu9Al4), formed of the phase γ', stable at low temperatures, brittle and hard, with electrical conductivity less than that of the β-phase.

The α2 phase formed at a temperature of 363 °C as a result peritectoid reaction between the phases α and γ2, has a face-centered cubic lattice, but with different parameters.

Metastable phase in alloys: β1 — basic-centered cubic crystal lattice (of 5.84 Å, Al — 11,9%), orderly; β' — with the elementary face-centered cubic crystal lattice (Al — 11,6%), very deformed; β1' — with the basic rhombic crystal lattice (a = to 3.67 Å, C = and 7.53 Å, Al — 11,8%), orderly; γ1-phase basic ortho-rhombic cell (a = of 4.51 Å, b = 5,2 Å, C = Å 4,22, Al — 13,6%), orderly. It is assumed the existence of other phases that are a variation of the phase β1'.

Determining the structure of alloys of Cu-Al is difficult. To obtain the equilibrium structures of the alloy requires a very large cooling rate (from 1 to 8°C/min, depending on the aluminum content). Such structures are detected in the etching of alloys in ferric chloride.

However, etching ferric chloride is not always possible to identify with certainty the phases in the alloys cooled at normal speed. In this case, to identify the true structure of the alloy Cu-Al applied a special technique using electrolytic polishing.

The structure of dual copper-aluminum alloys and multi-component bronzes on the basis of the system copper-aluminium in the equilibrium state is determined by the state diagram (Fig. 2).

Fig. 2. Diagram of phase transformations of aluminum bronze with an aluminum content of 12.07% (by weight)

However, production conditions during the casting of ingots, handling their pressure in hot and cold condition speed cooling and heating are significantly different from those under which the constructed equilibrium state diagram.

Therefore, the structure of cast and deformed semi-finished products different from those defined equilibrium state diagram.

To determine the properties and microstructure of the alloy in a metastable condition build With curves showing the kinetics of phase transformations depending on the cooling rate and isothermal aging at temperatures below the temperature of eutectoid transformation.

Single-phase alloy (α-aluminum bronze) plastic and well-handled pressure, two-phase alloy (α+γ2-aluminium bronze) with a high content of aluminum less ductile and are used mainly as foundry.

It should be noted that the actual content of aluminium industrial alloys varies widely, which affects the stability of the mechanical properties of cast and deformed semi-finished products from aluminum bronze.

Mechanical properties of aluminium bronze, pressure treated, (limits of the tensile strength σв, σпц of proportionality and yield strength σ0,2, relative elongation — δ and ψ contraction, impact strength an (COP) and Brinell hardness number (HB) depending on aluminum content, as shown in Fig. 3.

Fig. 3. Changes in mechanical properties aluminum bronze Cu-Al depending on the content of aluminum:

a — strip, deformed by 40% and annealed at a temperature of 650оС for 30 min.;

b — extruded bars and pipes from aluminium bronze Brazhmc10−3-1,5

This feature of aluminum bronzes is considered in foreign national standards (USA, Germany, UK, France, etc.). In these countries, to increase the stability of mechanical properties of aluminum bronze provides a narrower interval, the content of aluminum, which is approximately 1.5−2 times less than in similar bronzes used in Russia and the CIS (see alloy at 493 GOST, GOST 17328 and foreign alloys-analogues).

In the United States, France and Japan there are groups of bronzes of the type Brainz in which the required mechanical properties are achieved only by changing the aluminum content.

The effect of alloying elements on properties of aluminum bronzes

The two-component alloying of aluminum bronzes of different elements significantly modifies their properties. Basic alloying elements of the alloys Cu-Al are iron, manganese and Nickel. In aluminum bronzes, typically the content of iron and Nickel does not exceed 5.5, manganese 3% (by weight).

Iron in the solid state slightly soluble in the alloys Cu-Al and form an aluminum intermetallic compound Fe3Al composition that stands out as a separate phase in the form of fine particles. When the content in the alloy is about 1% Fe is formed a small quantity of fine particles, which are located near the field of eutectoid (α + γ2) and framing it. However, with the increase of iron content their number is increasing. So when the content of 4% Fe fine particles Fe3Al formed in the region α + γ2 and α. Fine particles of intermetallic compound Fe3Al inhibit the grain growth in aluminium bronzes at high temperatures. Under the influence of the iron, which greatly improves mechanical properties and delays the recrystallization temperature, in aluminum bronzes disappears the so-called phenomenon of «spontaneous annealing», leading to embrittlement of alloys. Iron crushing structure, stops the formation in Cu-Al alloys containing 8,5−11,0% Al, coarse γ2-phase, released in the form of continuous chains, causing fragility.

Iron, depending on its content in the alloy affects the structure, phase transformations and properties of aluminum bronzes as follows: when the content up to 1.2% it is in solid solution (α-phase), and when more content is released in the form of separate globular inclusions, which are in double and triple alloys containing Nickel. usually plotted as the k-phase. Approximate composition of k-phase: 85% Cu, 10% Al 5% Fe; when the content in the alloy from 1.2 to 5.5% of iron has a strong modifying effect on the change in the primary grains in the cast billet; when the content in the bronze > 5.5% of Fe this effect disappears. Therefore, industrial aluminum bronze, the iron content usually does not exceed 4%.

Iron hardens the aluminum bronze due to the increasing strength of the solid solution (α-phase) and highlight the k-phase. Alloys with high iron content-type БрАЖ10−10 have a high resistance to abrasion and erosion, however, are less resistant in sea water.

In case of additional alloying alloys of the system Cu-Al-Fe manganese and Nickel greatly increase the strength characteristics and corrosion resistance, change the structure and composition of k-phase.

Manganese is highly soluble in aluminum bronzes in the solid state. When the content of MP > 2% in alloys of the system Cu-Al markedly accelerated the transformation phases of the α + γ2 phase β (manganese lowers the eutectoid temperature and inhibits the dissolution of β-phase); when the Mn content>8% the collapse of the β-phase does not take place.

Feature of addition of manganese to aluminum bronze is the emergence in them when cooled, needle-like germ β-phase conversion to β-phase in the α+ γ2

The appearance of needle-shaped nuclei of the α-phase is particularly noticeable in the annealing of large-sized products. Therefore, the casting of marine propellers with variable thickness from 15 to 400 mm, widely used special aluminum-manganese bronze with a high content of manganese.

In the bronze type БрАЖ10−4, Brazh9−4 manganese is the leading element in determining the transformation kinetics of the β-phase by heating and improves the hardenability depth. In these bronzes is allowed the content of Mn to 1.5%. However, with increasing Mn content from 2 to 5% decreases the hardness of aluminum bronzes after tempering at a temperature of 800−1000°C. Therefore, to increase the hardness of aluminum bronzes during heat treatment must be not more than 0.5% Mn.

Manganese increases the mechanical and corrosion properties and improves technological characteristics of the alloys Cu-Al. Aluminium bronze, alloyed with manganese, have a high corrosion resistance, cold resistance and high deformability in hot and cold condition.

Nickel, infinitely soluble in the solid state in copper practically does not dissolve in aluminum (at a temperature of 560 °C the solubility is 0.02%). Nickel increases the surface area of the α-phase in the systems Cu-Al and Cu-Al-Fe. In the alloys of Cu-Al-Ni under the influence of Nickel in the region of solid solution with decreasing temperature significantly shifted in the direction of the copper angle, so they can be subjected to dispersion hardening. The ability to dispersion hardening of these alloys is found when the content of 1% Ni. Nickel raises the temperature of eutectoid decay β to α+γ2 to 615 °C, delays the transformation of α+γ2 β during heating. The Nickel effect becomes particularly prominent when its content is more than 1.5%. Thus, when the alloy contains 2% Ni β-phase appears at a temperature of 790 °C, when the content of 4% Ni — at the temperature of 830 °C.

Nickel has a beneficial effect on the structure eutectoid α+γ2 and pseudovector α + β significantly increases the resistance of the phase transformations of β-phase, and the casting and quenching promotes the formation of larger amounts of metastable β'-phase martensitnogo type. While α-phase becomes more rounded the shape, the structure becomes more uniform, increases the dispersion eutectoid.

Alloying Nickel aluminum bronze greatly improves their physical-mechanical properties (thermal conductivity, hardness, fatigue strength), cold resistance and anti-friction characteristics, corrosion and erosion resistance in sea water and weak hydrochloric solutions; heat resistance and recrystallization temperature without noticeable deterioration of the technological characteristics. When the content of Nickel alloys significantly increases the modifying effect of iron.

Aluminum bronze Cu-Al-Ni is rarely used. Nickel is usually injected in aluminium bronze in combination with other elements (primarily iron). The most widespread aluminium bronze type Brazhn10−4-4. The optimal properties of these bronzes are obtained when the ratio of Fe: Ni =1:1. When the content in these bronzes 3% Ni and 2% Fe k-phase can be released in two forms: in the form of small rounded inclusions of solid solution based on iron, alloyed with aluminium and Nickel, in the form of thin plates, the composition of the intermetallic compound NiAl.

The most widely deformed aluminium bronze the following systems: Cu-Al, Cu-Al-Fe, Cu-Al-Mn, Cu-Al-Fe-Mn, Cu-Al-Fe-Ni.

Aluminum bronzes are characterized by high corrosion resistance in carbon dioxide solutions, as well as in solutions of most organic acids (acetic, citric, lactic, etc.), but unstable in concentrated mineral acids. In solutions of sulfate salts, and caustic alkalis are more stable single-phase aluminum bronze of low aluminum content.

Aluminium bronze less other materials are subjected to corrosion fatigue.

Features of treatment of wrought aluminum bronzes

To obtain a homogeneous deformed semi-finished products with improved mechanical properties and high fatigue strength we recommend aluminum bronze continuous cast method and subsequent processing to produce a special method, which includes operations:

a)hot processing of cast billets with a total compression of 30%;

b)heat treatment at a predetermined temperature (t0) with a tolerance of ±2°C (heating to a predetermined temperature, exposure time 20 min per 25 mm material section);

C)quenching in water or oil at a temperature of 600 °C;

d)hot working at a temperature of 35−50°C less than that which was adopted during heat treatment at the stage of «b» depending on the aluminum content in the alloy (aluminum content must be determined with an accuracy of ±0,02%). The temperature of the heat treatment is determined by the empirical formula:

t=(1990 — 1000A)°C,

where, a content of aluminum in the alloy, % (by weight).

Graphic dependence of temperature on the content of aluminum under thermal and the second hot pressure treatment of aluminum bronzes is given in Fig. 4.

Fig. 4. The temperature from the content of the aluminum during heat and hot pressure treatment of aluminum bronzes:

1 — temperature heat treatment;

2 — temperature of hot forming

Beryllium bronze (copper-beryllium alloys)

Beryllium bronze is a unique alloy for a favorable combination of good mechanical, physicochemical and anti-corrosion properties. These alloys after quenching and aging have high tensile strength, elasticity, yield strength and fatigue fatigue, have high electrical conductivity, thermal conductivity, hardness, possess high creep resistance, high cyclic strength with minimal hysteresis, high resistance to corrosion and corrosion fatigue. They are frost — proof, non-magnetic and does not give sparks upon impact. Therefore, beryllium bronze used for the manufacture of springs and spring parts for critical applications, including membrane and parts of movements.

Fig. 5. State diagram of the system Cu-Be

The diagram shows that the copper beryllium forms a series of solid solutions. The region of solid solution α at a temperature of 864 °C amounts to 2.7% (by weight). With decreasing temperature the solubility limit of region α rather abruptly shifted to copper. At the temperature of eutectoid transformation 608 °C, it is 1.55% and decreases to 0.2% at a temperature of 300 °C, which indicates the possibility of refining beryllium bronze.

A significant change in the concentration of beryllium in the α-solid solution with decreasing temperature contributes to the dispersion hardening alloys Cu-Ve. The effect of dispersion hardening alloys Cu-Ve from the content of beryllium is shown in Fig. 6.

Fig. 6. The effect of beryllium content on the effect of dispersion hardening alloys Cu-Be: 1 — annealing at a temperature of 780 °C; 2 — annealing at a temperature of 780 °C + vacation at a temperature of 300°C

Heat treatment of beryllium bronzes is carried out at a temperature of 750−790°C With subsequent quenching in water to produce a supersaturated solid solution. In this state, beryllium bronze easy to carry, flexible operation, exhaust and other types of deformation. The second operation is heat treatment — holidaying at a temperature of 300−325°C. however, there is a β'-phase. These allocations are associated with significant stress of the crystal lattice that cause increased hardness and strength of alloys.

The result of eutectoid transformation of β-phase at lower temperature 608 °C is formed eutectoid α + β'. The α phase has a cubic face-centered lattice parameter which decreases with increasing content of beryllium. The β phase has a body-centred cubic lattice with a disordered arrangement of atoms. The crystal structure of β'- phase is the same as that of β-phase, but there is an ordered arrangement of the atoms of beryllium.

In practice, a binary copper-beryllium alloys are almost never used, the spread was three — and multicomponent alloys.

To slow down the phase transformation and recrystallization of obtaining a more homogeneous structure in Cu-Ve alloys injected Nickel or cobalt and iron. The total content of Nickel, cobalt and iron in beryllium bronzes ranges from 0.20 to 0.60% (by weight), including Nickel and cobalt, from 0.15 to 0.35 percent (by weight).

Introduction to Cu-Ve alloys of titanium, beryllium forming with the reinforcing phase, to slow them diffusion processes. Titanium, as a surface active element that reduces the concentration of beryllium grain boundaries and reduces the rate of diffusion in these zones. In beryllium bronze with additions of titanium observed homogeneous decay and, as a consequence, more uniform hardening.

The most beneficial effect on properties of beryllium bronze Titan has in the presence of Nickel. By the addition of titanium and Nickel beryllium alloys can be reduced to 1.7 and 1.9% (by weight).

Manganese in the alloys Cu Ve may partially replace the beryllium without significant reduction in Strength. Alloys Cu + 1% Be + 5−6% of MP and Cu + 0,5% Be + 10% Mn after dispersion hardening on mechanical properties close to beryllium bronze brand Brb2.

Magnesium supplementation in small quantities (0,1%) increases the effect of dispersion hardening beryllium bronze, and ranging from 0.1 to 0.25 per cent — significantly reduce its ductility.

Lead, bismuth and antimony for beryllium bronzes are quite harmful impurities that can impair their deformability in the hot state.

In a standard Cu-Be alloys allowed the contents of Al and Si not more than 0.15% of each element. In such concentrations these elements do not render harmful influence on the properties of the alloys.

Manganese bronze

Manganese bronze is characterized by high mechanical properties. These alloys are perfectly handled the pressure of both hot ive cold state, allowing for deformation in cold rolling to 80%.

Manganese bronze is different corrosion resistance, high heat resistance and is therefore used for the manufacture of parts and products, operate at elevated temperatures. In the presence of manganese, the recrystallization temperature of copper is increased to 150−200°C.

Fig. 7. State diagram of the system Cu-Mn

Manganese at elevated temperatures unlimitedly soluble in copper both in liquid and in the solid state. When the content in the alloy of 36.5% magnesium (by weight) the temperature of the liquidus and solidus of the system is the same and is 870 ± 5 °C. With decreasing temperature is a series of transformations are highlighted in a new phase. The region of solid solution at lower temperatures is reduced. Manganese bronze, containing less than 20% of magnesium, in the range of temperatures from room temperature up to the melting point, are single-phase. In Fig. 8. the dependence of mechanical properties of manganese bronzes from the content of the manganese.

Fig. 8. Changes in mechanical properties of the alloys Cu-Mn depending on the manganese content and the yield strength σ0,2; b — tensile strength σb; relative elongation δ

The most widely bronze Brmc5, which is well-deformed in hot and cold conditions, has a high corrosion resistance, and retains properties at elevated temperatures.

Siliceous bronze

Silicon bronze has high mechanical spring and antifriction properties stand against the corrosion and wear resistant. These alloys are perfectly handled the pressure of both hot and cold welded with steel, soldered, both soft and hard solders. They are not magnetic, do not give sparks upon impact and do not lose their ductility at very low temperatures.

State diagram of the alloy system Cu-Si:

Fig. 9. State diagram of the system Cu-Si

As can be seen from the diagram, the boundary of the solid solution α at a temperature of 830оС reached 5.4% Si (by weight) and with decreasing temperature moves towards copper. The α phase has a cubic face-centered lattice with parameter a=(3,6077+0,00065) Å where the silicon concentration, %.

At temperatures > 577 OS to the right border of the α-solid solution there is a new co-phase with a hexagonal close-Packed lattice (a=2,5550 Å, C=Å 4,63644). A distinctive feature of the phase is noticeable by the color change in polarized light from light to dark brown. At a temperature of 557оС occurs a phase transformation to → α+ γ.

The nature of the change of silicon in α-solid solution with decreasing temperature indicates the possibility of refining some of the alloys of the system Cu-Si. But as the effect of dispersion hardening of alloys is weak and not applied in practice.

The greatest spread the word got the silicon bronze with additions of manganese and Nickel. Less frequently used two-component bronzes with additives of tin, zinc, iron and aluminum.

Alloying copper-silicon bronze manganese improves their mechanical properties and corrosion resistance.

State diagram of the system Cu-Si-Mn:

Fig. 10. State diagram of the system Cu-Si-Mn. Isotherm saturation region of the solid solution

Despite the shift of the boundary region of α with decreasing temperature in the direction of the copper corner, the effect of refining alloys Cu-Si-Mn is weak.

The addition of Nickel markedly increases the mechanical properties of silicon bronze. Silicon with Nickel to form the intermetallic compound (Ni2Si), which is significantly soluble in copper. With decreasing temperature (from 900 to 500 ° C) solubility in Ni2Si copper is dramatically reduced and released when the dispersion particles of intermetallic compounds strengthen the alloys. Heat treatment (hardening and aging) allows to increase the strength characteristics and hardness of these alloys is almost 3 times compared with the annealed alloys. After hardening alloys Cu-Si-Ni have high ductility and is processed in a cold state.

The change in the tensile strength of these alloys depending on the content of Ni2Si and method of heat treatment:

Fig. 11. The change in the strength of alloys of the system Cu-Ni-Si depending on the content of Ni2Si and method of heat treatment: 1 — annealing at a temperature of 900−950°C; aging at a temperature of 350−550°C; 2 — annealing at 800 °C; 3 — annealing at a temperature of 900−950°C

Additives of cobalt and chromium have on siliceous bronze the same effect as Nickel, however, the effect of dispersion hardening of alloys under the influence of silicides of cobalt and chromium is much weaker.

Additives of small amounts of Sn (0.5%) significantly increased, but the iron reduces the corrosion resistance of silicon bronze. For this reason, siliceous bronze, pressure treated, the content of Fe should not exceed 0.2−0.3% (by weight).

Zn additive in the range of 0.5 to 1.0% when melting silicon bronze contributes to the improvement of their technological properties.

Alloying silicon bronze aluminum increases its strength and hardness but the alloys of the system Cu-Si-Al did not spread because of their poor welding and brazing.

Harmful impurities in silicon bronze, pressure treated, are arsenic, phosphorus, antimony, sulfur and lead.

Corrosion properties of silicon bronze

Silicon bronze has excellent resistance to corrosion when exposed to marine, industrial and rural atmospheres, fresh water and salt water (at a flow rate of 1.5 m/sec), the hot and cold fluids and the cold concentrated alkali and sulphuric acid, cold solutions of hydrochloric and organic acids, chlorides and sulfates of light metals. They are fairly stable in atmosphere, dry gases: chlorine, bromine, fluorine, sulfide, fluoride and hydrogen chloride, sulfur dioxide, and ammonia but will corrode in these environments, in the presence of moisture.

However, the silicon bronze is poorly resistant to aluminium hydroxide, chlorides and sulphates of heavy metals. They corrode quickly and in acidic mine waters containing Fe2 (S04)3 and in solutions of salts of chrome acids.

Peculiarities of heat treatment of siliceous bronze

Bright annealed silicon bronzes (including heating and cooling) should be performed in water steam. The oxide film formed on the surface of semi-finished products in the annealing process, can be easily removed by etching at room temperature in 5% strength sulfuric acid.

Tin bronze

Tin bronze alloys of different compositions based on the system Cu-Sn. A consolidated list of domestic tin bronze, pressure treated, and their foreign alloys-analogues are given in table. 4.

A consolidated list of domestic tin bronze, pressure treated, and their foreign counterparts

Tin-phosphor bronze:

Brand Patriotic bronze	The analogue of the US	Analog Germany	Analog Japan
Brof2−0,25	-	-	-
Brof4−0,25	С51100	CuSn4 (2.1016)	C5111
-	C53400	-	-
Brof6,5−0,15	-	CuSn6 (2.1020)	C5191
-	C51000	-	-
-	C53200	-	-
Brof6,5−0,4	-	-	-
Brof7−0,2	-	SuSn6 (2.1020)	Section of a c5210
Brof7−0,2	-	SuSn8 (2.1030)	-
Brof8,0−0,3	C52100	The same	C5212
-	C52400	-	-

Tin-zinc bronze:

Brand Patriotic bronze	The analogue of the US	Analog Germany	Analog Japan
Broc4−3	-	-	-
-	-	CuSn6Zn6 (2.1080)	-

Tin-Nickel bronze:

Brand Patriotic bronze	The analogue of the US	Analog Germany	Analog Japan
-	C72500	CuNi9Sn2 (2.0875)	-
-	C72650	-	-
-	C72700	-	-
-	C72900	-	-

Tin-zinc-lead bronze:

Brand Patriotic bronze	The analogue of the US	Analog Germany	Analog Japan
Brocs4−4-2,5	-	-	-
-	С54400	-	-
Brocs4−4-4	-	-	-

State diagram of the system Cu-Sn shown in Fig. 12.

Fig. 12 state Diagram of the system Cu-Sn

The phase α-solid solution of tin in copper (crystal lattice face-centered cubic) plastic hot and cold condition.

The β and γ phase is stable only at elevated temperatures, and with decreasing temperature decompose at high speed. Phase δ (Cu31Sn8, the lattice γ '-phase) is a decay product of γ-phase (or β') at a temperature of 520 °C hard and brittle.

The dissolution of δ-phase α + Cu3Sn (ε-phase) starts at 350 °C. With decreasing temperature the decay of δ-phase occurs very slowly (long-term annealing after cold deformation 70−80%). Almost in alloys containing up to 20% Sn, ε-phase is missing.

Technical tin bronze the tin content ranges from 2 to 14%, rarely up to 20%.

The alloys of the system Cu-Sn depending on the tin content consist either of homogeneous crystals of α-solid solution or crystals eutectoid α and α + β.

The process of diffusion of tin in the bronze is slow Dendritic structure disappears only after repeated cycles of thermomechanical processing. For this reason, the process of processing tin bronzes pressure difficult.

In the process of melting tin bronze deoxidized with phosphorus, so the majority of the binary alloys Cu-Sn contain residual amounts of phosphorus. Phosphorus is considered to be alloying additive for the content in the alloy is > 0.1 percent.

The main alloying additions of tin bronzes, except phosphorus, are lead, zinc, Nickel.

The influence of alloying elements

Phosphorus in the interaction with the copper gives the chemical compound of Sisr (14.1% P), which is at a temperature of 714 °C with the copper forms a eutectic (the content of R — 8,4% (by weight). In the ternary system Cu-Sn-P at a temperature of 628 °C formed a triple eutectics, containing, %:80,7 Cu, Sn and 14,8 4,5 P.

From the state diagrams of the system Cu-Sn-P (Fig. 13) shows that by increasing the SN content and decreasing temperature, the saturation limit of the α-solid solution drastically shifts toward the copper corner.

Fig. 13. State diagram of the system Cu-Sn-P: a — copper angle; b — polymetric sections of the copper corner of the Cu-Sn-P at a constant tin content

When the content of tin in the bronzes > 0.3% P latest is released in the form of inclusions fosrenol eutectic. Tin bronze with the content of 0,5% R and more easily destroyed during hot deformation, as fosfina the eutectic is melted. So maksimalnoe content of phosphorus in the tin bronze, pressure treated, is 0.4%. At such content of phosphorus tin bronze possess optimal mechanical properties, have increased the normal module of elasticity, limits of elasticity and fatigue. Applying annealing-homogenization, after kotoroya a significant part of the phosphorus passes into the α-solid solution, it is possible to improve the deformability of tin bronzes with a high content of phosphorus.

Small additions of zirconium, titanium, boron and niobium also improves the machinability of tin bronzes pressure in hot and cold condition.

Lead is practically insoluble in tin bronzes in the solid state. During the solidification of the alloy stands out as a separate phase in the form of dark inclusions between the dendrites. Lead significantly improves the density, antifrictional and machinability of tin bronzes, but significantly lowers their mechanical properties. Antifriction tin bronzes contain up to 30% Pb.

Zinc is highly soluble in tin bronzes in the solid state and, slightly changing the structure of the alloys significantly improves their technological properties.

Nickel offsets the boundary of the solid solution α in the direction of the copper corner (Fig. 14).

Fig. 14. State diagram of the system Cu-Sn-Ni: and — cut copper angle when the content of 2% Nickel; b — area of saturation of the solid solution at room temperature. Copper corner.

The crystal lattice of α-solid solution under the effect of Nickel is not changed, but slightly increases its setting (-0,007). At low concentration of tin in the heterogeneous region there is a new phase (Ni4Sn), which, depending on the speed of solidification is allocated or in the form of small needle-like crystals (fast cooling) or light blue inclusions. The liquidus in the alloy Cu-Sn alloying with Nickel increases considerably. At a temperature of 539 °C the eutectoid transformation α + γ α + β'. Phase δ' in contrast to the phase δ of the binary system Cu-Sn is polarized.

Nickel improves mechanical properties and corrosion resistance of tin bronzes, refines their structure, and when the content of 1% is a useful Supplement. When the content > 1% Ni alloys though are improved, however they deteriorate machinability pressure. A particularly sharp impact Nickel has on tin-phosphor bronze. At the same time the Ni content in the range of 0.5−1% has no effect on the structure nor on the properties of tin-zinc bronzes.

The influence of impurities

The impurities of aluminum, magnesium and silicon are very harmful to the tin bronzes. These elements included in the solid solution, although, and enhance the mechanical properties of the bronzes, however, they are smelting vigorously oxidized, forming refractory oxides, which are situated at the grain boundaries, breaking the connection between them.

Harmful to tin bronzes, pressure treated, are also impurities of arsenic, bismuth, antimony, sulfur and oxygen. The latter reduces friction characteristics of tin bronzes.

Corrosion properties

Tin bronze has good resistance against exposure to atmospheres (rural, industrial, marine). In sea water they are more resistant than copper and brass (bronze durability in contact with sea water increased with increasing tin content). Nickel also enhances the corrosion resistance of tin bronzes in sea water, and lead at high levels — reduces. Tin bronze resistant in salt water.

Tin bronze is satisfactorily resistant to corrosion in an atmosphere of superheated steam at a temperature of 250 °C and pressures not higher than 2.0 MPa, when exposed to room temperature solutions of alkali, dry gases (chlorine, bromine, fluorine and hydrogen compounds, oxides of carbon and sulfur, oxygen) of carbon tetrachloride and ethyl chloride.

Tin bronze is unstable in the environment of mineral (nitric, sulfuric) acids and fatty acids, alkalis, ammonia, cyanides, ferrous and sulfur compounds, gases (chlorine, bromine, fluorine) at a high temperature, acidic mine waters.

Corrosion of tin bronzes under the action of sulfuric acid increases in the presence of oxidants (К2СЮ7, Fe2 (S04)3, etc.) and is reduced by 10−15 times in the presence of 0.05% benzylcyanide.

The corrosion rate of tin bronzes under the influence of a number of agents are as follows, mm/year:

Alkali:

hot 1.52 m …

at 293 K …0,4−0,8

ammonia solutions at room temperature… of 1.27−2.54 mm

acetic acid at room temperature …0,025−0,6

a pair of H2S at 100 °C 1,3 …

wet sulfur dioxide …2,5

wet and dry water vapour (depending on flow rate) …0,0025−0,9

Tin bronze exposed to corrosion cracking under tension by the action of nitrate of mercury.

Brass, iron, zinc and aluminium in the process of electrochemical corrosion are the protectors for tin bronzes.