Applications of alloys in daily life, industrial production, science and technology and military affairs.

We often melt (physically change) two or more metals (or metals and nonmetals) to form a substance with metallic characteristics, which is called an alloy.

Edit the classification and universality of alloys in this section.

English: Alloy

Classification of alloys

According to the different structures, the main types of alloys are: (1) mixed alloy (* * * molten mixture), which is an alloy formed by crystallization of various components of the alloy when the liquid alloy solidifies, such as solder and bismuth cadmium alloy. (2) solid molten alloy, in which solid solution is formed when liquid alloy solidifies, such as gold and silver alloy; (3) Intermetallic alloys are alloys in which components form compounds with each other, such as brass (β-brass, γ-brass and ε-brass) composed of copper and zinc. Many properties of alloys are superior to pure metals, so alloys are often used as application materials (see ferroalloy and stainless steel).

Commonality of alloys

All kinds of alloys have the following commonalities: (1) The melting point of most alloys is lower than that of any constituent metal; (2) Hardness is generally greater than that of any metal in its composition; (Special case: Sodium-potassium alloy is a liquid and used as a heat conductor in atomic reactors) (3) The electrical conductivity and thermal conductivity of the alloy are lower than those of any component metal. Using this characteristic of alloy, materials with high resistance and high thermal resistance can be manufactured. It is also possible to manufacture materials with special properties, such as adding 15% chromium and 9% nickel to iron to obtain corrosion-resistant stainless steel. Suitable for chemical industry. (4) Some alloys have strong corrosion resistance (such as stainless steel). 2. Common alloys are ductile iron, manganese steel, stainless steel, brass, bronze, white copper, solder, hard aluminum, 18K gold and 18K platinum.

Edit this part of steel

Brief introduction of steel

Steel is an alloy composed of iron, carbon, silicon, manganese, phosphorus, sulfur and a small amount of other elements. Except Fe, the content of C plays a major role in the mechanical properties of steel, so it is collectively called iron-carbon alloy. It is the most important and commonly used metal material in engineering technology.

Classification and nature

According to the different carbon content, iron-carbon alloys can be divided into steel and pig iron. Steel is an iron-carbon alloy with a carbon content of 0.03% ~ 2%. Carbon steel is the most commonly used common steel, which is easy to smelt, easy to process and low in price, and can meet the requirements in most cases, so it is widely used. According to the different carbon content, carbon steel can be divided into low carbon steel, medium carbon steel and high carbon steel. With the increase of carbon content, the hardness of carbon steel increases. Adding one or more alloying elements on the basis of carbon steel can change the structure and properties of steel and make it have some special properties, such as high hardness, high wear resistance, high toughness and corrosion resistance. The alloying elements often added in steel are silicon, tungsten, manganese, chromium, nickel, molybdenum, vanadium, titanium and so on. China is rich in alloy steel resources, but chromium and cobalt are scarce, and the grade of manganese is low.

About pig iron

Iron-carbon alloy with carbon content of 2% ~ 4.3% is called pig iron. Pig iron is hard and brittle, but it is resistant to pressure and wear. According to the different forms of carbon in pig iron, it can be divided into white iron, gray iron and ductile iron. The carbon in white iron is distributed in the form of Fe3C, and its fracture is silvery white, hard and brittle, so it cannot be machined, so it is also called steelmaking pig iron. Carbon is distributed in the form of flake graphite, which is called gray iron. Wear resistance. If carbon is distributed in spherical graphite, it is called ductile iron, and its mechanical properties and processability are close to those of steel. Special cast iron can be obtained by adding special alloying elements to cast iron. If chromium is added, the wear resistance can be greatly improved, which has a very important application under special conditions. For this elite talent, it is also the most scarce in China at present. At present, there is a steel talent network, which is a professional recruitment and job search website for talents in ferroalloy industry.

Edit this section of aluminum alloy.

brief introduction

Aluminum alloy plastic material

Aluminum is a widely distributed element, and its content in the earth's crust is second only to oxygen and silicon, and it is the highest among metals. Pure aluminum has a low density of 2.7 g/cm3, good thermal conductivity, electrical conductivity (second only to Au, Ag and Cu), good ductility and high plasticity, and can be used in various mechanical processing. Its chemical properties are active, and it rapidly oxidizes in the air, forming a dense and firm oxide film.

Features and attributes

The outstanding characteristics of aluminum alloy are low density and high strength. Aluminum-manganese and aluminum-magnesium alloys formed by adding manganese and magnesium to aluminum have good corrosion resistance, good plasticity and high strength. They are called rust-proof aluminum alloys and are used to manufacture oil tanks, containers, pipelines and rivets. The strength of hard aluminum alloy is higher than that of rust-proof aluminum alloy, but its corrosion resistance decreases. These alloys include Al-Cu-Mg system and Al-Cu-Mg-Zn system. The strength of the newly developed high-strength hard aluminum is further improved, and the density is lower than that of ordinary hard aluminum 15%. Can be extruded for motorcycle frames and rims. Al-Li alloy can be used to manufacture aircraft parts and high-grade sports equipment that can bear loads.

App application

At present, high-strength aluminum alloys are widely used to manufacture airplanes, ships and trucks, which can increase their load capacity and speed, and have the characteristics of seawater corrosion resistance and magnetic avoidance.

Edit this aluminum alloy overview.

Aluminum alloy aluminum alloy is the most widely used non-ferrous metal structural material in industry, which has been widely used in aviation, aerospace, automobile, machinery manufacturing, shipbuilding, chemical industry and other industries. With the rapid development of science and technology and industrial economy in recent years, the demand for aluminum alloy welded structural parts is increasing, which makes the welding research of aluminum alloy continue to deepen. The wide application of aluminum alloy promotes the development of aluminum alloy welding technology. At the same time, the development of welding technology has expanded the application field of aluminum alloy, so the welding technology of aluminum alloy is becoming one of the research hotspots. Pure aluminum has a low density (ρ=2.7g/m3), about 1/3 of iron, and a low melting point (660℃). Aluminum has high plasticity (δ: 32 ~ 40%, ψ) because of its face-centered cubic structure. However, the strength of pure aluminum is very low, and the σb value of annealed aluminum is about 8kgf/mm2, so it is not suitable for structural materials. Through long-term production practice and scientific experiments, people gradually strengthened aluminum by adding alloying elements and applying heat treatment, and obtained a series of aluminum alloys. The alloy formed by adding some elements can maintain the advantages of pure aluminum, such as light weight, but also has high strength. σb values can reach 24 ~ 60 kgf/mm2 respectively. This makes its "specific strength" (the ratio of strength to specific gravity σb/ρ) better than many alloy steels, making it an ideal structural material, which is widely used in machinery manufacturing, transportation machinery, power machinery and aviation industry. Aircraft fuselage, skin, compressor and so on often use aluminum alloy to reduce their own weight. Aluminum alloy is used instead of steel plate material for welding. The structural weight can be reduced by more than 50%. Aluminum alloy has low density, but its strength is relatively high, close to or higher than that of high-quality steel. It has good plasticity, can be processed into various profiles, has excellent electrical conductivity, thermal conductivity and corrosion resistance, and is widely used in industry, and its consumption is second only to that of steel. Aluminum alloys can be divided into two categories: cast aluminum alloys, which are used in as-cast state; Deformed aluminum alloys can withstand pressure processing and can be processed into aluminum alloys of various shapes and specifications. Mainly used for manufacturing aviation equipment, building doors and windows, etc. According to the processing methods, aluminum alloys can be divided into wrought aluminum alloys and cast aluminum alloys. Wrought aluminum alloys can be divided into non-heat treated aluminum alloys and heat treated aluminum alloys. The mechanical properties of aluminum alloy strengthened by non-heat treatment can not be improved by heat treatment, but only by cold working deformation. It mainly includes high-purity aluminum, industrial high-purity aluminum, industrial pure aluminum and rust-proof aluminum. Heat-treatable strengthened aluminum alloys can improve their mechanical properties through heat treatment such as quenching and aging, which can be divided into hard aluminum, forged aluminum, superhard aluminum and special aluminum alloys. Some aluminum alloys can obtain good mechanical properties, physical properties and corrosion resistance through heat treatment. Cast aluminum alloys can be divided into aluminum-silicon alloy, aluminum-copper alloy and aluminum-magnesium alloy according to chemical composition. Al-Zn alloy and Al-RE alloy, among which Al-Si alloy includes simple Al-Si alloy (which can not be strengthened by heat treatment and has low mechanical properties and good castability) and special Al-Si alloy (which can be strengthened by heat treatment and has high mechanical properties and good castability). Xiangyun torch is made of aluminum.

Edit this Duan Chun aluminum product.

Pure aluminum can be divided into two types: smelting products and pressure processing products. The former is represented by the chemical composition al, and the latter is represented by the Chinese pinyin LU (aluminum, industrial). All kinds of aircraft use aluminum alloy as the main structural material. The skin, beams, ribs, trusses, clapboard frames and landing gears of aircraft can all be made of aluminum alloy. According to the different purposes of aircraft, the amount of aluminum is also different. Economic-oriented civil aircraft is widely used because of its low price. For example, the aluminum alloy used in Boeing 767 aircraft accounts for about 865,438+0% of the structural weight of the aircraft. Because military aircraft require good performance, the amount of aluminum is relatively reduced. For example, the F- 15 high-performance fighter with a maximum flight speed of Mach 2.5 uses only 35.5% aluminum alloy, and some aluminum alloys have good low-temperature performance, ranging from-183 to -253 [2oc]. It can work in the environment of liquid hydrogen and liquid oxygen. It has no chemical reaction with concentrated nitric acid and unsymmetrical dimethylhydrazine, so it is a good material for making liquid rockets. The fuel tank, oxidizer tank, inter-tank section, inter-stage section, tail section and instrument cabin of Apollo spacecraft launched by Saturn V carrier rocket are all made of aluminum alloy. The crew cabin, front fuselage, middle fuselage, rear fuselage and instrument cabin of the space shuttle are all made of aluminum alloy.

Edit the repair process of forgings in this section.

Repair is an important part of aluminum alloy die forging process. Because aluminum alloy is soft at high temperature, high viscosity and poor fluidity, it is easy to stick to the mold, resulting in various surface defects (folding, burrs, cracks, etc. ). Before the next process, it must be polished and repaired to remove surface defects, otherwise the defects will be further expanded in the subsequent process, and even the forgings will be scrapped. The tools used for repair include pneumatic grinder and pneumatic small milling cutter.

Edit this section of pressure processing aluminum alloy.

Aluminum alloy pressure processing products can be divided into seven categories: rust prevention (LF), hardness (LY), forging (LD), superhard (LC), cladding (LB), special (LT) and brazing (LQ). Commonly used aluminum alloy materials include annealing (M annealing), hardening (Y) and hot rolling (R).

Edit this part of aluminum material.

Aluminum and aluminum alloys processed into certain shapes are collectively called aluminum materials, including plates, belts, foils, tubes, rods, wires, profiles and so on. Aluminum alloy plate.

1. aluminum-plastic plate

Aluminum-plastic plate is a new type of material, which is composed of 3003 aluminum-manganese alloy and 5005 aluminum-magnesium alloy plate with surface treatment and paint coating, with pe plastic as the core layer and polymer adhesive film compounded through a series of processes. It not only retains the main characteristics of the original composition materials (aluminum alloy plate and non-metallic polyethylene plastic), but also overcomes the shortcomings of the original composition materials. In addition, many excellent material properties have been obtained. Product features: colorful decoration, weather resistance, corrosion resistance, impact resistance, fire prevention, moisture resistance, sound insulation, heat insulation, earthquake resistance, light weight, easy processing and molding, easy handling and installation, etc. Specification of aluminum-plastic plate: thickness: 3mm, 4mm, 6mm, 8mm, width: 1220mm, etc. Standard size of 2440mm, 3000mm and 6000mm aluminum-plastic panels: 1220*2440mm aluminum-plastic panels Application: it can be used for decoration of curtain walls, internal and external walls, hallways, restaurants, shops and conference rooms. , can also be used for the renovation of old buildings, such as counters, furniture surfaces, interior and exterior walls of vehicles, etc.

2. Aluminum veneer

Aluminum veneer is made of high-quality aluminum alloy from world-renowned large enterprises, and then sprayed with American PPG or Aksu PVDF fluorocarbon coating. Aluminum veneer is mainly composed of panel, reinforcement of bones and muscles, ear hook and so on. The characteristics of aluminum veneer are: light weight, good rigidity, high strength, nonflammability, good fire resistance, good processing technology, wide color selection, excellent decorative effect, easy recycling and environmental protection. Application of aluminum veneer:

3. Aluminum honeycomb panel

Aluminum honeycomb panel adopts composite honeycomb structure, which is made of high-quality 3003H24 alloy aluminum plate or 5052AH 14 high-manganese alloy aluminum plate as base material and aluminum alloy honeycomb core material by hot pressing. Aluminum honeycomb panel provides architects with rich choices from panel materials, shapes, joints, installation system to color and surface treatment, and can show rich roof performance effects. It has excellent design freedom. It is a new material with convenient construction, ideal comprehensive performance and remarkable thermal insulation effect, and its excellent performance has attracted people's attention. Aluminum honeycomb panels have no standard size, and all panels are made by the factory according to the design drawings, which are widely used in the fields of ceilings, partitions, doors, insulated carriages, billboards and so on. This product will inject environmental protection into China building materials market.

4. Aluminum honeycomb perforated sound-absorbing ceiling board

The structure of perforated sound-absorbing aluminum honeycomb ceiling board is perforated aluminum alloy panel and perforated back plate, which is directly bonded with aluminum honeycomb core by high-quality adhesive to form aluminum honeycomb sandwich structure, and a layer of sound-absorbing cloth is stuck between honeycomb core, panel and back plate. Because the honeycomb core in the honeycomb aluminum plate is divided into many closed cells, the air flow is prevented, the sound wave is hindered, the sound absorption coefficient is improved (up to more than 0.9), and the strength of the plate itself is improved. The size of the veneer can be made larger, which further increases the design freedom. According to the acoustic design of the room, we can design different perforation rates and control the sound absorption coefficient of the composite structure within a certain range, which not only achieves the design effect, but also controls the cost reasonably. By controlling the perforation aperture and spacing, the perforation rate and maximum perforation rate can be changed according to the customer's requirements.