月: 2023年1月

What Is Naval Brass?

Naval brass is a type of special brass made by adding a small amount of tin (about 1%) to 64 brass (a copper alloy consisting of 60% copper and 40% zinc). It is also called naval brass because of its high resistance to seawater and is mainly used for ships and in the chemical industry.

Admiralty brass, which is made by adding tin and arsenic to C73 brass, is also known as a special brass with tin added. However, its use in Japan is limited due to its inferior resistance to corrosion compared to aluminum brass (Alblac) to which aluminum is added.

Uses of Naval Brass

Naval brass is used in marine applications due to its high resistance to seawater. Its excellent corrosion resistance also makes it suitable for a wide range of other applications, including bolts, nuts, valve stems, and condenser plates, as well as for chemical and other industrial equipment.

A related copper alloy, made by adding a little less than 1% each of lead and manganese to Naval brass, has excellent punching and fatigue resistance and is called instrument valve brass (JIS: C6711). As the name suggests, this alloy is widely used for instrument valves such as organs.

Characteristics of Naval Brass

Naval brass is characterized by its high corrosion resistance. Ordinary brass is also said to be a relatively corrosion-resistant alloy, but it is known that dezincification, or dezincification corrosion, occurs. This dezincification corrosion is a phenomenon in which the zinc component in the alloy preferentially dissolves, leaving the copper component unbalanced, and thus corrosion is more likely to occur. This is not a problem when the zinc content is low, but since ordinary brass alloys typically contain about 30~40% zinc, this corrosion cannot be ignored and has been said to cause reliability problems under corrosive conditions.

Naval brass has excellent corrosion resistance to both freshwater and seawater. While adding tin increases hardness and strength, it is said to decrease elongation.

Naval brass is particularly resistant to seawater, but in recent years, the use of alloys with higher corrosion resistance has been increasing, such as aluminum brass (Alblac), an alloy made by adding aluminum to brass, and cupronickel, a copper alloy containing nickel. The use of traditional brass is said to be declining.

What Is a Toroidal Coil?

Toroidal coils are coils made by winding an electric wire around a circular magnetic core.

By forming a closed magnetic circuit called a toroid, toroidal coils have characteristics different from those of ordinary coils. In a coil with wires wound in a cylindrical shape, the induced magnetic field lines are radiated outward through the coil, which may affect surrounding materials.

Toroidal coils can minimize the effect on the surroundings because the magnetic field lines are closed.

Applications of Toroidal Coils

Toroidal coils are used in applications that take advantage of the characteristics of the closed magnetic circuit structure with low leakage flux. They are widely used in electronics, such as choke coils in power supply circuits, filters for eliminating harmonics in high-frequency circuits, and inductors and capacitors.

For example, in cellular phones and wireless LAN, ordinary inductors may not work properly because they are affected by the environment near the circuit in the ultra-high frequency band. Toroidal coils can be used to solve this problem.

Toroidal coils are also used as coils for large equipment such as nuclear fusion devices, superconducting magnets, or charged particle accelerators. They are also used in stator-side coils for electric motors.

Principle of Toroidal Coils

A coil wound with an electric wire generates a magnetic flux at right angles to the wire when an electric current flows through it. Toroidal coils consist of copper wire wound around a doughnut-shaped toroidal core. Because the core is a circle, the magnetic flux stays inside and hardly comes out to the outside. If the copper wire is wound many times, the magnetic fluxes overlap and a strong magnetic field can be obtained.

Since the magnetic flux generated does not easily leak outside, the coil efficiency is extremely high, and the magnetic flux has the advantage of hardly affecting other elements. The cores used in toroidal coils are made of iron-based steel sheets. Specifically, FeSi silicon steel plate cores, nanocrystalline alloy cores, FeSi-based alloy cores, and Fe(CO)5 carbonyl cores are used. They have low flux leakage and stable inductance.

Characteristics of Toroidal Coils

Toroidal coils can confine magnetic field lines generated by passing an electric current through a coil wound around a doughnut-shaped magnetic body, enabling compactness and high magnetism and preventing leakage of magnetic field lines to the outside.

The three basic components of an electric circuit are the RLC, the “R” resistance, the “L” inductance (the device is an inductor), and the “C” conductance (the device is a capacitor).

Toroidal coils are inductors that provide greater inductance than air-core coils, and the higher the frequency of the current flowing through them, the greater the effect, so they can be used to remove harmonics. Adding another coil to the magnetic material of the toroidal coils makes a high-frequency transformer.

Furthermore, by combining it with a capacitor C, which is inversely proportional to the frequency, and the higher the frequency, the easier it is for the current to pass through, various filters can be configured.

Other Information on Toroidal Coils

Role of Toroidal Coils

1. Smoothing Action
Toroidal coils have the property that when a current tries to flow through a copper wire, the coil tries to keep the current flowing, and when the current decreases, the coil tries to keep the current flowing. This is called Lenz’s law, which states that when the magnetic flux through a closed circuit changes with time, an induced electromotive force is generated that produces a magnetic field in a direction that prevents the flux from changing.

Toroidal coils are used for smoothing in power supply circuits that convert AC to DC and for high-frequency filters, taking advantage of this property.

2. Mutual Induction
Mutual induction is the induction of power from one coil into the other when two coils are placed close together. Using this principle, toroidal coils are used in power transformers.

The output voltage of a power transformer varies according to the ratio of the number of turns of the primary coil to the number of turns of the secondary coil; multiple voltages can be obtained by installing an intermediate tap on the secondary coil.

3. Electromagnet Action
The electromagnet of the coil is used in relays that open and close circuits. It is also applied to generators, electric motors, bells, buzzers, etc.

What Is Tin-Free Steel?

Tin-Free Steel is an alternative surface-treated steel sheet that include the usage of tin material.

Tin-Free Steel features an electrolytic chromic acid treatment applied to cold-rolled carbon steel sheets to form metallic chromium and chromium hydrated oxide layers on the surface layer. Electrolytic chromic acid treatment improves corrosion resistance. Compared to tin-plated steel sheets, it has a lower environmental impact and is easier to recycle.

It is also characterized by a relatively low cost compared to tin-plated steel sheet.

Uses of Tin-Free Steel

1. Canning

Tin-Free Steel is widely used as a material for canning. The reason is that it has the durability needed to protect food from factors such as oxygen and moisture while the food is stored.

2. Electronic Components

In electronic components, thin sheets are used. The reason is that they possess both the flexibility and conductivity of metals.

3. Building Materials

They are sometimes used as a building material for roofing, walls, siding, roof drains, etc. Reasons are for its strength, durability, and aesthetic appearance.

4. Vehicle Parts

 They are also used as a material for vehicle parts.

5. Household Products

They may be used in household products, e.g., cookware, dishes, toys, trash cans, washers and dryers, etc.

Properties of Tin-Free Steel

1. Corrosion Resistance

Tin-Free Steel is protected from rust and corrosion by an electrolytic chromic acid treatment that forms a chromium hydrated oxide layer on the surface. The chromium hydrated oxide layer is very hard and chemically stable, and is characterized by excellent corrosion resistance. It also improves the adhesion of paints.

Electrolytic chromic acid treatment is a treatment method that forms a chromium hydrated oxide layer on the surface of iron and steel. This treatment forms a hard, chemically stable chromium hydrate oxide layer on the surface of iron and steel to protect the surface.

2. Paint Adhesion

A chromium hydrate oxide layer is formed on the surface of tin-free steel by electrolytic chromate treatment. The chromium hydrate oxide layer is very hard and chemically stable, and therefore, the adhesion of the paint is high.

The chromium hydrated oxide layer is formed uniformly, allowing paint to be applied evenly, improving paint adhesion, simplifying the painting process, and providing a beautiful finish.

Tin-free steel is also used for surfaces such as building materials and home appliances because the paint does not peel easily and remains beautiful for a long time after painting.

3. Mechanical Strength and Workability

Tin-Free Steel is made from cold-rolled coils, which gives it a fine surface metallurgical structure, high strength, and good workability. It is easy to form and process, and is used in a wide range of applications such as automotive parts and construction materials.

4. Low Environmental Impact

Tin-Free Steel does not use tin and does not contain hazardous substances such as lead and cadmium, and thus has a low environmental impact. It is also suitable for recycling as it is reused as steel.

5. Water Resistance

Tin-Free Steel has a tin-plated surface, making it impervious to moisture and humidity. It is used in waterproof applications such as roofing and exterior wall materials to enhance the durability and livability of buildings.

6. Heat Resistance

Tin-Free Steel is heat resistant. The reason is that the chromium hydrated oxide layer formed on the surface is chemically stable even at high temperatures. It is used for food containers used in high-temperature environments such as ovens and microwave ovens, and for automotive parts that require high-temperature processing.

7. Impact Resistance

Tin-Free Steel forms metallic chromium and chromium hydrated oxide layers on its surface. The formed chromium hydrate oxide layer is extremely hard and chemically stable, and has excellent wear resistance. In addition, because cold-rolled coils are used, the surface metallurgical structure is fine, and the mechanical strength is high and impact resistance is excellent.

It is also suitable for products used in environments subject to severe friction and impact, such as automotive parts and home appliances.

Examples of applications include automobile doors, hoods, wheels, and other parts, as well as housings and exterior parts of home appliances. It is also used as a building material when strength to withstand impacts such as earthquakes is required. 

8. Abrasion Resistance

The chromium hydrated oxide layer formed on the surface of tin-free steel is extremely hard and chemically stable, making it highly resistant to abrasion.

Because of its excellent abrasion resistance, it can be used for a long period of time in environments where friction and wear are severe, such as automotive parts and building materials. For example, automotive parts such as doors, hoods, and other open/close parts, and wheels are examples of applications.

In building materials, it is used in components exposed to the outdoors, such as roofing and exterior wall materials. Roofing and exterior wall materials are exposed to the natural environment, such as wind, rain, and ultraviolet rays, and require materials with high surface hardness and excellent abrasion resistance.

Other Information on Tin-Free Steel

1. Color Types

Tin-Free Steel is characterized by the ability to express a variety of colors by applying electrolytic coloring treatment to its surface. Specifically, an oxide film is generated by the electrolytic coloring solution, and depending on the thickness of the oxide film, the color changes due to interference, reflection, and refraction of light.

Tin-Free Steel’s electrolytic coloring process can express a variety of color tones. Therefore, tin-free steel is also used in applications where color is important, such as building materials and home appliances.

2.Sulfurization-Resistant Blackening

Tin-Free Steel generally has good resistance to sulfide blackening. This is because it is treated with electrolytic chromic acid to form a chromium hydrated oxide layer on the surface. The formed chromium hydrate oxide layer acts as a protective film to prevent the occurrence of sulfide blackening and protects tin-free steel from sulfide blackening. However, depending on the operating environment and conditions, sulfide blackening may occur, requiring appropriate maintenance.

The blackening that occurs in food cans is a blackish-brown deposit caused by the reaction of hydrogen sulfide contained in the can material with the acidic food ingredients that fill the can. Food cans are made of metal materials such as iron and aluminum, which contain trace amounts of sulfides. Heat sterilization and other processes acidify the food ingredients that fill the can, and under these acidic conditions they react with hydrogen sulfide to produce black sulfide deposits.

What Is a Titanium Copper Alloy?

Titanium copper alloy, classified as C1900, is a copper-based alloy with titanium added to improve its properties. This alloy stands out for its excellent ductility, corrosion resistance, heat resistance, wear resistance, and fatigue resistance. It offers a cost-effective alternative to beryllium copper, possessing similar high-strength characteristics.

Its utility spans various applications, particularly in electronic components, due to its remarkable bend formability, strength, and workability. Occasionally, minute amounts of iron (Fe) and other elements are introduced to enhance its properties further. It is also known by other names, such as copper-titanium alloy and Cu-Ti alloy.

Uses of Titanium Copper Alloy

With its high strength and superior bend formability, titanium copper alloy is especially beneficial for electronic device connectors undergoing complex bending. Its applications include:

• High-strength springs for electronic devices, communication equipment, and measuring instruments.
• Terminals for electronic components, switches, connectors, relays, brushes, jacks.
• Connectors in smartphones and PCs.
• Camera module components, like spring materials for lens support.
• Automobile connectors.
• Battery terminals.
• Materials for vacuum tube components.

Properties of Titanium Copper Alloy

Comparable in hardness and strength to steel, titanium copper alloy also boasts superior high-temperature strength. It maintains its tensile strength up to approximately 300℃, featuring a higher softening temperature relative to other copper alloys. Its fatigue properties and corrosion resistance are on par with those of copper-beryllium alloys, and it is non-magnetic.

Types of Titanium Copper Alloy

Available in various compositions and hardness classifications, such as EH, 1/4H, and SH, based on the treatment temperature and duration. Key types include:

1. C1990

Comprising 2.90-3.50% titanium and the remainder copper, C1990 matches or exceeds the properties of beryllium copper, offering exceptional strength and stress relaxation properties. Variants with enhanced strength, bendability, and conductivity are available without altering the composition.

2. NKT322

This alloy, enhanced with a small addition of Fe to improve strength and bend formability, contains 2.9 to 3.4% titanium, 0.17 to 0.23% iron, and the remainder copper. It is noted for its stress relaxation resistance and ability to maintain contact force at high temperatures.

3. Other

Options include titanium copper alloy with Cu plating for improved corrosion resistance and solderability. Some products are designed to achieve high electrical conductivity, minimizing heat generation and enhancing heat dissipation in electronic components.

Other Information on Titanium Copper Alloy

1. Manufacturing

As an age-hardenable alloy, it undergoes solution annealing and age-hardening processes in non-oxidizing atmospheres or vacuums to avoid oxidation. Cold working after solution treatment enhances mechanical strength, though age hardening reduces cold workability, allowing for limited cold working post-aging.

2. Chemical Composition

The alloy’s titanium content ranges from 1.8% to 3.5%, with copper making up the remainder. Some variants include up to 0.2% iron, offering enhanced strength and bendability, achieving proof stress of 1 GPa or higher.

What Is a Slug?

Slugs are byproducts generated during the melting and refining of metals such as iron and copper.

It is produced when impurities contained in metal ores dissolve and react with oxides such as lime and silica. In addition to metals, they are sometimes used as raw materials for cement and glass, or reused as materials for railroads and pavements. The reuse of slug is expected to make effective use of resources and reduce waste, but since it can cause environmental pollution, it must be treated appropriately in the manufacturing process.

Uses of Slugs

1. Raw Material for Cement

Slugs are materials that mainly contain oxides such as silica, alumina, and iron oxide. Silica, alumina, and iron oxide are used as raw materials for cement. When heated together with lime, the main ingredient of cement, Slugs undergo a chemical reaction and become a solidified material. Slugs can be used in cement to remove oxides and improve the strength of the cement.

Silica is a compound called silicon oxide whose chemical formula is SiO₂. Alumina is a compound called aluminum oxide with the chemical formula Al₂O₃.

2. Raw Materials for Glass

It mainly contains oxides such as silica and alumina, which are used in glass production because these components are similar to silica acid and alumina, which are major components of glass.

3. Material for Road and Railroad Substructures

The high density and durability of glass make it an ideal material for use in road and rail substructures. Its low permeability also allows it to drain well, making it an excellent drainage material for road and railroad construction.

4. Raw Material for Construction Materials, Limestone, Etc.

Slugs contain components such as silica, alumina, iron oxide, and calcium, which are used in building materials such as limestone and cement. Being a solid, it can be used as it is when used as a building material.

5. Stabilization of Roadbeds

Slugs are also used to stabilize roadbeds for roads and railroads. Since it is solid, it can be mixed with soil to improve the stability of roadbeds. It can also improve soil compaction due to its high density.

6. Soundproof Walls, Protective Walls, and Pavement Materials

Due to its excellent acoustic properties, it is sometimes used for soundproofing walls, protective walls, and pavement materials.

7. Soil Conditioner

Slugs are also used as soil conditioners in agriculture. It is used as a fertilizer in agriculture because it neutralizes soil acidity and provides nutrients. The iron and calcium content in Slugs is also used as a nutrient for crop growth.

8. Ground Improvement Material

Slag is suitable for ground improvement because it increases the density of soil and improves its compressibility. As a ground improvement material, it is also used in road and railroad construction.

9. Environmental Purification Material

The components contained in slugs are effective in adsorbing and removing pollutants. For example, it is sometimes used for water purification. Slugs contain metal ions such as iron and aluminum, and these ions are used in the treatment necessary for water purification.

10. Raw Material for Manufacturing Recycled Iron Powder

Slugs are also used as a raw material for the manufacture of recycled iron powder. Recycled iron powder is an iron powder produced by reusing waste materials such as iron scale and steel scrap generated in the iron manufacturing process, and is used as a raw material for manufacturing recycled iron powder.

Properties of Slugs

Slugs are produced during the process of melting metal ores at high temperatures to separate the metal from the impurities. The basic process is as follows

1. Melting of Metal Ores

Melting metal ores at high temperatures initiates the dissolution process to separate metals from impurities. Impurities contained in the metal ore have a lower melting point than the ore itself, so they tend to dissolve during melting.

2. Oxygen Blowing

The molten slugs contain oxides as well as metals. When oxygen is blown in to remove these oxides along with impurities, the impurities are oxidized and become slugs, making them easier to dissolve.

3. Reaction of Impurities

After impurities are oxidized by oxygen blowing and dissolved into the molten slag, they react with additives such as lime and silica to form slugs. This reaction leaves the slugs as a liquid with properties different from those of metals.

4. Extraction of Slugs

Since slugs are lighter than metal, they float on the surface in liquid form, which makes it easier for slugs to separate from metal. After the metal and slugs are separated, the slugs are cooled and solidified, and processed as a byproduct.

Types of Slugs

Slugs come in a variety of types depending on the type of metal ore and refining method, and there are several ways to classify them. Below are some of the typical classification methods for Slugs.

1. Classification by Material Type

Since slugs are produced from different materials depending on the type of metal ore, they may be classified based on their materials. Typical slug materials include iron slugs, copper slugs, lead slugs, zinc slugs, and aluminum Slugs.

2. Classification by Chemical Composition

Slugs are sometimes classified based on their chemical composition because they have different chemical compositions depending on impurities and additives in the ore. Examples include lime slugs, silica slugs, alumina slugs, and manganese slugs.

3. Classification by Manufacturing Process

Slugs are by-products generated during the metal ore refining process and may have different properties depending on the manufacturing process. For example, blast furnace slugs are generated in the blast furnace steelmaking process, while molten slugs are generated in the melting furnace coppermaking process. Thus, Slugs may be classified based on the manufacturing process.

Types of Slugs

Typical slugs, their generation processes, and reuse methods are shown in the table below.

Name of Slugs	Generation Process	Reuse Method
Iron Slugs	Produced by melting metallic ores at high temperatures and blowing oxygen into them	Used as raw material for cement and concrete, material for road and railroad substructures, and alternative material for gravel and pavement materials
Copper Slugs	Produced by melting ores at high temperatures and blowing oxygen into them during the copper manufacturing process	Used as cement, pavement material, abrasive, and road substructure material
Aluminum Slugs	Produced by melting metal ores containing aluminum at high temperatures and blowing oxygen into them	Used in cement, soil conditioners, pavement materials, and the manufacture of metal parts
Silicon Slugs	Generated in the process of reducing silicon ore	Used as an additive in the manufacture of cement, limestone, soil conditioners, building materials, and steel production
Steel Slugs	Generated in the process of steel manufacturing	Raw material for cement and concrete, material for road and rail substructures, substitute material for gravel, additive to remove impurities during steel refining, fuel for steelmaking processes
Zinc Slugs	Generated in the smelting process of zinc ore	Cement, soil improver, material for road substructures, metal recycling
Nickel Slugs	Generated in the refining process of nickel ore	Cement, soil improver, material for road substructure, metal recycling

Other information on Slugs

1. Utilization of Slugs

In addition to metal refining, slugs are used in a wide range of fields, including environmental measures, construction, and agriculture.

For example, slugs are sometimes used as a soil conditioner. Slugs contain lime, iron, and other components that adjust the pH value of the soil and increase the absorption of nutrients in the soil. Slugs also improve air permeability and drainage, which can promote the growth of crops.

Furthermore, it is effective in environmental measures. Slugs are sometimes used as adsorbents for acid rain and soil pollutants. Lime slugs are particularly effective in neutralizing acid rain and helping to protect the environment.

In the construction field, slugs are used as raw materials for road and railroad substructure materials and building materials. It is attracting attention as an environmentally friendly material with excellent durability and longevity.

2. JIS Standards Related to Slugs

JIS (Japanese Industrial Standards) related to slug aggregate includes the following slug aggregate is a type of construction material made from molten slugs generated during the smelting of ferrous and nonferrous metals.

1. JIS A 5011 (slug aggregate for concrete)
   Blast furnace slugs aggregate
   Ferronickel slug aggregate
   Copper slugs Aggregate
   Electric furnace slug aggregate
2. JIS A 5012 (Blast furnace slugs fine aggregate for concrete)
3. JIS A 5015 (Steel slugs for roads)
4. JIS A 5021 (Recycled aggregate H for concrete)

What Is Spinel?

Spinel, composed of magnesium and aluminum with the formula MgAl₂O₄, combines high hardness and durability. This mineral, both naturally occurring and artificially synthesized, finds applications in industries and medicine due to its biocompatibility and physical properties.

Uses of Spinel

• Ceramics: For high-temperature applications in semiconductors, optical equipment, and more due to its thermal stability.
• Electronic Materials: As a substrate and in capacitors for its insulating properties and microwave compatibility.
• Catalysts: In automotive exhaust purification and petroleum refining for its chemical activity.
• Optical Materials: For laser diodes and lenses, benefiting from their transparency and optical performance.
• Jewelry and Pigments: As a gemstone and in coloring ceramics and glass.
• Magnetic Materials: In magnetic disks and speakers, utilizing their magnetic properties.
• Refractories: For heat-resistant bricks and coatings in industrial furnaces.
• Camera Lenses: Leveraging its exceptional optical clarity.

Properties of Spinel

• Durability: Noted for its hardness and scratch resistance, attributed to its strong ionic bonds and crystal structure.
• Heat Resistance: Capable of enduring high temperatures without significant thermal expansion or structural degradation.
• Corrosion Resistance: Chemically stable against acids and alkalis, maintaining integrity in harsh environments.
• Electrical Insulation: An effective insulator, prevents electron movement and ensures high-frequency and microwave passage.
• Optical Properties: Highly transparent to ultraviolet and visible light, with minimal internal defects and impurities.

Other Information on Spinel

Shades of Spinel

Spinel exhibits a wide range of colors, influenced by its chemical composition and the substitution of ions within its structure. Variants include red spinel, colored by chromium ions; blue spinel, with iron ions; and black spinel, rich in magnesium and iron. Mixed hues such as pink, brown, and orange spinels arise from the incorporation of manganese, chromium, and iron ions, showcasing spinel’s versatile color palette.

What Is a Cyclotron?

A Cyclotron is an accelerator for charged particles (negatively charged electrons, positively charged protons, ions, etc.) that repeatedly swirls the charged particles to increase their speed.

A cyclotron is a type of accelerator that accelerates particles by applying a potential difference that switches at high speed to the gap between two straight sections of electrodes (dee electrodes), which are shaped like the letter D in the alphabet.

Uses of Cyclotrons

Cyclotrons are used in a variety of fields to take advantage of the effects that occur when accelerated charged particles collide with a target (e.g., to produce isotopes that do not exist naturally, to modify semiconductors, etc.). One example is the production of short-lived radiolabeled compounds for PET (Positron Emission Tomography).

Radiolabeled compounds used in PET have short lifetimes and must be manufactured in cyclotrons as they are used. Recently, medical facilities are increasingly equipped with small cyclotrons for PET.

Another application is to improve the performance of semiconductors by semiconductor irradiation. Semiconductors can be modified by irradiating them with charged particles to improve their electrical properties.

Other applications include the production of radioisotopes for use in SPECT (Single Photon Emission Computed Tomography), research radioisotopes, radiopharmaceuticals, and nuclear physics research.

Principle of the Cyclotron

Cyclotrons use the force exerted on charged particles as they pass through a magnetic field (Lorentz force). The backbone of a cyclotron is a disk-shaped part consisting of two Dee electrodes in the shape of the letter D. The image of a circular shape is formed by pasting the vertical bars of the D and the flip side D together.

The D electrode is placed in a magnetic field created by an electromagnet. This is to make use of the Lorentz force to move the ions. When a charged particle is introduced into the magnetic field of the cyclotron, the Lorentz force causes the particle to bend and move in a circular orbit. At this time, they will orbit in a circular path along the shape of a disk formed by two dee electrodes.

Halfway around the disk, the particle reaches another dee electrode, at which point a potential difference is created between the electrodes to accelerate the particle. When the particles return to the original electrode after completing half the circumference, the potential difference can be reversed to accelerate them again. This process is repeated to accelerate the charged particles.

As the speed of the charged particle increases, the radius of gyration increases, allowing the particle to be extracted from the periphery of the disk.

Other Information on Cyclotrons

1. Limit of Acceleration

As the speed of the charged particle approaches the speed of light, its mass increases due to relativity effects, making it more difficult to bend. Therefore, the radius increases beyond the initial calculation, and acceleration cannot be achieved as originally designed. Therefore, there is a limit to the acceleration using a cyclotron.

Synchrocyclotrons and synchrotrons were therefore considered. Synchrocyclotrons are cyclotrons that enable acceleration up to high speeds by slowing down the switching of the electric field according to the speed of the ions.

Synchrotrons, on the other hand, are constructed with a different concept than cyclotrons. Unlike cyclotrons, which gradually increase the orbit radius, synchrotrons accelerate by changing the strength of the magnetic field and the period of electric field switching while maintaining a constant circular orbit.

2. Advantages of Cyclotrons

Although cyclotrons have limitations in acceleration, one advantage that synchrotrons do not have is the ability to continuously accelerate particles by pouring them into the cyclotron one after another.

They can also produce high intensity particle beams. These features are suitable for the production of isotopes and the modification of semiconductors, and the features are successfully used in applications.

What Are Galvalume Steel Sheets?

Galvalume steel sheets are metallic steel sheets plated with aluminum, zinc, and silicon. They are also called aluminum-zinc alloy-plated steel sheets.

Galvalume building materials are rust-resistant and have a long durability period despite being a metallic material.

Another advantage is that it is robust and earthquake resistant. It has high solar heat reflectance and can suppress surface and indoor temperatures, especially in summer.

Uses of Galvalume Steel Sheets

Galvalume is widely used as a building material due to its excellent durability, heat resistance, and workability. It is also often used as an exterior material for houses because of its high design quality. Because of its high corrosion resistance, it is mainly used for exterior walls and roofs of buildings.

Galvalume is also used in a wide range of other applications, including machinery and equipment.

The following are examples of where Galvalume steel sheets are used:

• Pipes for agriculture and marine transportation
• Highway soundproofing walls
• Various industrial facilities and industrial equipment exposed to corrosive environments
• Electrical equipment such as microwave ovens and vending machines
• Automobiles
• Shipbuilding

Galvalume steel sheets have a wide range of applications as shown above due to their excellent properties.

Characteristics of Galvalume Steel Sheet

Galvalume steel sheet is a rolled steel sheet plated with galvalume. Plating is mainly done by melting, since it is an alloy. The composition of galvalume is 55% aluminum, 43.4% zinc, and 1.6% silicon.

Aluminum is characterized by long-term durability and heat resistance. Zinc also produces galvanic action. Galvanic action is the oxidation of zinc, which forms an oxide film and has a rust-preventive effect. It is also called a sacrificial corrosion prevention effect.

Galvalume steel sheet is a steel material that has the durability and heat resistance of aluminum and the corrosion resistance of zinc, as described above.

Types of Galvalume Steel Sheets

Galvalume is a steel material with the characteristics described above. It is widely used in applications ranging from construction materials to machinery and equipment.

Super galvalume steel sheet, also called SGL steel sheet, is a next-generation steel sheet. It is a steel material developed to further improve the durability of galvalume steel sheets, and is manufactured by adding about 2% magnesium to the plating. The magnesium makes the plating structure even denser and provides high corrosion resistance.

Other Information on Galvalume Steel Sheets

1. How to Use Galvalume Steel Sheets

Galvalume steel sheets are installed and laid in the same manner as tin roofs and steel pipes. However, galvalume steel sheets have maintenance requirements, one of which is flushing. By focusing on flushing areas that are not easily exposed to rainwater, the rust-preventing effect can be enhanced.

In addition, in mountainous areas where roads are prone to freezing, sodium chloride and calcium chloride are sometimes sprayed to prevent freezing. If these substances adhere to the roof, rusting may easily progress. Therefore, it is necessary to thoroughly wash the roof with water after spraying anti-freezing agents.

2. History of Galvalume Steel Sheets

Prior to the development of galvalume steel sheet, tin and other materials were used as exterior materials. Galvanized tin is a steel material plated with hot-dip zinc. The galvanic action of the zinc makes the material corrosion resistant, and it was widely used around the world.

In the 1960s, acid rain caused by pollution from industrialization became a social problem. Even corrosion-resistant tin corrodes when rain with a low PH level falls, resulting in a problem of low durability. Against the backdrop of this problem, galvalume steel was introduced.

Galvalume steel was developed by the American steel company Bethlehem Steel in 1972. It is more than three times more durable than tin, depending on installation conditions and other factors. As a result, it has become widely used throughout the world as an alternative to tin. 

3. Life Span of Galvalume Steel

Galvalume is known to have a longer service life than tin. The life span of exterior materials made of tin is about 10 to 20 years. In contrast, galvalume has a life expectancy of 25 to 35 years.

The actual lifespan varies depending on the manufacturer and the environment in which it is used, and in some cases it can be used for 50 years or more.

In recent years, a steel material called super galvalume steel (SGL steel) has also become popular; SGL steel is a more durable version of galvalume steel and can be expected to last 30 to 50 years.

What Is Carbon & Graphite Fiber?

Carbon & graphite fiber, also known as carbon fiber, is a type of fiber composed entirely of carbon (C).

Two primary types of carbon & graphite fiber exist: PAN-based and pitch-based. These fibers inherit many properties of carbon, such as excellent heat resistance and electrical conductivity. Carbon & graphite fiber is highly valued across numerous industries due to its lightweight nature, strength, and hardness.

However, challenges related to its cost currently limit its usage in several fields.

Applications of Carbon & Graphite Fiber

Carbon & graphite fiber find extensive application as a substitute for metallic materials, leveraging their lightweight properties while retaining strength. Its flexibility, electrical conductivity, corrosion resistance, and flame retardance widen its utility.

Typically used in composite materials alongside resins, ceramics, and metals, carbon & graphite fiber is integral in various sectors. It is employed in aerospace for aircraft, rockets, and satellites, in medical equipment like prosthetics and wheelchairs, and notably in automotive manufacturing for improved fuel efficiency and weight reduction.

In addition, carbon & graphite fiber’s strength and elasticity make it popular in sports equipment such as golf clubs, tennis rackets, and bicycles. Its potential applications extend to architecture and civil engineering, where it may enhance earthquake resistance in concrete structures or replace steel frames and suspension bridge cables.

Types of Carbon & Graphite Fiber

Carbon & graphite fiber can be categorized based on the raw material:

1. PAN Carbon & Graphite Fiber

Made from carbonized polyacrylonitrile (PAN) fibers, PAN-based carbon & graphite fiber is prevalent in industrial and leisure applications. It typically consists of filaments with diameters ranging from 5 to 15 μm, bundled in regular or large tows.

2. Pitch-Based Carbon & Graphite Fiber

Derived from pitch, a solid residue obtained from crude oil distillation, pitch-based carbon & graphite fiber offers adjustable elasticity. It is categorized into mesophase and isotropic pitch fibers, each tailored for specific applications such as automotive brake pads or machinery requiring vibration resistance.

Production Methods of Carbon & Graphite Fiber

1. PAN-Based Carbon & Graphite Fiber
PAN fibers undergo oxidation at 200-300°C to create a cyclic molecular structure. Subsequent carbonization at temperatures exceeding 1,000°C converts the molecular structure into a carbon crystal. Further graphitization at temperatures above 2,000°C yields graphite fiber.

2. Pitch-Based Carbon & Graphite Fiber
Coal or petroleum pitch is converted into fibers, which are then sintered. Precursor fibers are obtained through a process involving melt-spinning, stabilization, flame resistance treatment, carbonization, and graphitization.

What Is Cut Wire?

Cut wire, metal wire cut into lengths equal to its diameter is used as an abrasive in shot blasting and peening for polishing and paint removal. Made from fine wire (0.3 to 3 mm diameter) of materials like steel, stainless steel, aluminum alloys, copper, and zinc, it comes in various hardness levels (40 to 600 Hv) to suit different applications. Edgeless cut wire with rounded edges is also available.

Uses of Cut Wire

Different materials offer distinct benefits:

• Steel Cut Wire: Durable, used for deburring cast products.
• Stainless Steel Cut Wire: Hard (300-600 Hv), resistant to corrosion and acids, suitable for polishing die-cast aluminum and stainless steel.
• Aluminum Cut Wire: Soft (40-60 Hv), ideal for deburring and achieving smooth finishes.
• Alloy Aluminum Cut Wire: Moderately hard (~100 Hv), good for stain removal and polishing.
• Copper and Zinc Cut Wire: Used for deburring and paint stripping.

In welding, a cut wire can enhance weldment in submerged arc welding, particularly for thick plates and high-carbon steel to prevent cracking.

Features of Cut Wire

Cut wire’s primary attributes include:

• High abrasive power and durability, boosting efficiency and reducing costs.
• Consistent grain size and hardness enhance quality.
• Low crushing requirement, minimizing dust, improving the work environment, and reducing waste.

Various types of cut wire cater to specific needs. Stainless steel cut wire (SUS304, SUS430) offers rust resistance and durability, while copper cut wire excels in paint stripping.