What is bronze?
What is Bronze and what is it made of?
Bronze is a type of alloy composed mainly of copper. It is a mixture of copper with other elements such as tin, aluminum, beryllium, silicon, manganese, cadmium, zirconium, titanium, magnesium and iron.
All copper alloys, except pure copper and the copper-zinc (brass) and copper-nickel (white copper) series, can be classified as bronze.
The addition of other elements to the copper in bronze increases its resistance and gives it specific properties. Bronze has high compressive strength and its high elasticity, resistance to softening, and resistance to corrosion and wear make it a useful material for a variety of applications. Although it can be difficult to process, these properties have led to a wide range of uses for bronze.
Types of Bronze
How many types of bronze are there?
Bronze can be classified into several categories based on its main elements. These include tin bronze (including tin and phosphor bronze), aluminum bronze, beryllium bronze, silicon bronze, manganese bronze, chromium bronze, cadmium bronze, zirconium bronze, chromium zirconium bronze, titanium bronze , magnesium bronze and iron bronze, among others.
Tin bronze
The type of copper-based alloy that has tin as its main element is known as tin bronze. Tin bronze used in the industrial sector typically contains between 3% and 14% tin.
Tin bronze with less than 5% tin content is ideal for cold working processes. On the other hand, tin bronze with tin content ranging from 5% to 7% is suitable for hot working. For foundry applications, tin bronze with more than 10% tin content is preferred.
Tin bronze is widely used in various industries, including shipbuilding, chemistry, machinery and instrumentation. It is mainly used to manufacture wear-resistant parts such as bearings, shaft bushings and elastic components such as springs, as well as anti-corrosion and anti-magnetic parts.
aluminum bronze
The type of copper-based alloy that has aluminum as its main element is known as aluminum bronze. Aluminum bronze has superior mechanical properties compared to brass and tin bronze.
In practice, aluminum bronze contains 5% to 12% aluminum, with aluminum content between 5% and 7% providing the best plasticity, making it ideal for cold working. However, when the aluminum content is greater than 7% to 8%, the strength of the alloy increases, but its plasticity decreases significantly. Therefore, it is mainly used in cast form or after hot working.
In terms of wear and corrosion resistance, aluminum bronze outperforms brass and tin bronze in atmospheric acid, seawater, seawater carbonic acid and most organic acids.
Aluminum bronze can be used to manufacture high-strength and wear-resistant parts such as gears, shaft sleeves and helical gears, as well as highly corrosion-resistant elastic elements.
Beryllium bronze
The type of copper alloy that has beryllium as its main element is known as beryllium bronze. The beryllium content in beryllium bronze typically ranges from 1.7% to 2.5%.
Beryllium bronze is characterized by its high elastic limit and fatigue limit, excellent wear and corrosion resistance, good conductivity and thermal conductivity, non-magnetism and no sparks when impacted.
It is mainly used for manufacturing critical springs in precision instruments, watch gears, bearings and bushings that work under high speed and high pressure, as well as welding electrodes, explosion-proof tools, navigation compasses and other vital components.
silicon bronze
The type of bronze that has silicon as its main element is known as silicon bronze. In addition to silicon, silicon bronze used in the industrial sector also contains traces of manganese, nickel, zinc or other elements.
Silicon is a copper-bound solid solution, with a maximum solubility of 5.3% at 852°C, which decreases as the temperature decreases. However, the hardening effect of aging is not significant, and generally no strengthening heat treatment is carried out.
The silicon content of deformable silicon bronze ranges from 1% to 4%. As the silicon content increases, a brittle phase may appear, reducing the plasticity of the alloy.
Silicon bronze has a narrow crystallization temperature range, good fluidity and higher mechanical properties compared to tin bronze. It can be used as a substitute for tin bronze in the machinery manufacturing industry.
Manganese bronze
Manganese bronze is a type of alloy that has copper as the base element and manganese as the main alloying element. The main types of manganese bronze are QMn1.5 (Cu-1.5Mn) and QMn5 (Cu-5Mn), among others.
Chrome bronze
Chrome bronze is a type of copper alloy that contains 0.4% to 1.1% chromium. Chrome bronze can be strengthened through quenching, aging or cold deformation quenching and aging treatments.
At the eutectic temperature of 1072°C, the maximum solubility of chromium in copper is 0.65%. As the temperature decreases, the solid solubility of chromium decreases rapidly and chromium particles are precipitated after solid solution and aging treatments.
The addition of chromium significantly improves the recrystallization temperature and thermal resistance of the alloy, but slightly decreases the conductivity of copper. The conductivity of solution-treated chrome bronze rod is 45% IACS, which increases to 80% IACS after aging treatment. The softening temperature of aged chrome bronze is 400°C, twice that of cold-worked copper.
This alloy can be used in both casting and deformation states. When aluminum and magnesium are added as alloying elements of chromium bronze, a thin and dense oxide film forms on the surface of the Cu-Cr alloy that is firmly bonded to the base metal, improving high-temperature oxidation resistance and Alloy heat resistance. The aluminum and magnesium content in the alloy is generally no more than 0.3%.
Cadmium Bronze
Cadmium bronze is a special type of bronze that has cadmium as the main alloying element and sometimes 0.35% to 0.65% chromium is added. Cadmium and copper form a solid solution at high temperatures, but solid solubility decreases rapidly as the temperature decreases.
The low cadmium content results in a weak strengthening effect on the precipitated phase particles, and therefore the alloy cannot be hardened by heat treatment and can only be strengthened through cold deformation.
Cadmium bronze has high conductivity and thermal conductivity, good wear resistance, wear reduction performance and corrosion resistance, as well as good processing performance. It is widely used in manufacturing conductive, heat-resistant and wear-resistant parts for electrical devices.
It is important to emphasize that the volatile matter of cadmium is toxic and the material must be prepared using fusion methods, paying attention to safety measures during the fusion process. The domestic grade of cadmium bronze is QCd1. It is available in the form of plates, strips, rods and wires.
Its main applications include motor commutators, switching elements, spring contacts, waveguide cavities, high-resistance transmission lines, contact welding joints and electrodes, rollers, among others.
Zirconium Bronze
Zirconium bronze is a special type of bronze that has zirconium as the main alloying element, and sometimes a small amount of zirconium is added to improve its strength. Common grades of zirconium bronze are QZr0.2 and QZr0.4.
It has good thermal resistance and creep resistance and maintains good plasticity and conductivity at high temperatures. Zirconium bronze is produced by the melting method.
It is mainly used as resistance welding parts and high-strength electrode materials. The use of zirconium bronze is becoming increasingly widespread in the steel industry due to its high conductivity, thermal conductivity and ease of processing.
Bronze chrome zirconium
Zirconium chromium bronze is an alloy that has high strength, hardness, electrical conductivity and thermal conductivity, as well as good wear resistance. After aging treatment, its hardness, strength, electrical conductivity and thermal conductivity are significantly improved, making welding easier.
It is widely used in applications such as motor commutators, spot welding machines, seam welding machines, electrodes for butt welding machines and other components that require strength, hardness, conductivity and high temperature conductivity.
As an electric spark electrode, chromium zirconium bronze can produce an ideal mirror surface with good vertical performance. It can achieve effects that are difficult to achieve with pure red copper, such as flaking, and is suitable for difficult-to-machine materials such as tungsten steel.
Zirconium chrome bronze grades include C18150, C18200, C15000 and C15100.
Titanium bronze
Titanium bronze refers to a copper alloy that has titanium as the main alloying element. It is a new type of elastic material that has good workability, both cold and hot. Through heat treatment, the properties of titanium bronze can be greatly improved and strengthened. For example, its tensile strength can be increased from 686 MPa to 1009 MPa.
Titanium bronze is used in the manufacture of high strength, high elasticity and high wear resistance elastic elements, electrical switches, elastic relay elements, membrane housings, diaphragms, gears, bearings, bearings and journal bushings, among others. forms.
magnesium bronze
Magnesium bronze is a type of alloy of magnesium and copper. The domestic grade of magnesium bronze is QMg0.8. It is a binary alloy of copper and magnesium and is commonly used as a conductive material such as cables and can replace cadmium bronze in many applications.
Magnesium bronze is mainly supplied in wire form and is primarily used to manufacture conductive components such as aircraft cables and antennas.
iron bronze
Iron bronze is a type of bronze that has iron as its main element. Copper-iron alloys, also known as iron-bronze, are represented by the C19400 alloy in America.
Through heat treatment, the precipitation of iron in the alloy improves its strength and heat resistance. The tensile strength in its hardened state can reach 415-485 MPa and its conductivity can reach 60% IACS.
Iron bronze is widely used as a lead frame material for integrated circuits and is included in the ASTM B465-85 standard in the United States. This standard also includes the alloys C19200, C19500 and C19600, which have iron contents of 0.8% to 12%, 10% to 20% and 9% to 12%, respectively, and phosphorus contents of 0.01% to 0.04%, 0.01% to 0.35% and 0.25% to 0.35% respectively.
In China, the equivalent of C19400 alloy is QFe2.5-0.1 iron bronze.
