1. Classification of Non-ferrous Metal Casting and Representation Method of Product Grades
I. Classification of Non-ferrous Metal Casting
(1) Non-ferrous metal casting is divided into five categories: heavy metals, light metals, precious metals, semi-metals, and rare metals.
(2) Non-ferrous metal casting can be classified by alloy system: heavy non-ferrous metal alloys, light non-ferrous metal alloys, precious metal alloys, rare metal alloys, etc. By the use of alloys, it can be further divided into: deformation (pressure processing alloys), casting alloys, bearing alloys, printing alloys, hard alloys, soldering materials, intermediate alloys, metal powders, etc.
(3) Non-ferrous materials can be classified by chemical composition: copper and copper alloys, aluminum and aluminum alloys, lead and lead alloys, nickel and nickel alloys, titanium and titanium alloys. When classified by shape, they can be divided into: plates, strips, bands, foils, tubes, rods, wires, profiles, etc.
II. Representation Method of Product Grades
(1) Naming Principle The naming of product grades for non-ferrous metal casting and alloy products stipulates that Chinese pinyin letters or international elemental symbols are used as theme word codes to indicate their major categories, such as using L or AL to represent aluminum, T or Cu to represent copper. After the theme word, the order of component numbers combined with product categories is used to indicate. That is, the code after the theme word can represent the state, characteristics, or main components of the product, such as LF representing rust-proof (F) aluminum alloy; LD representing forging (D) aluminum alloy; LY representing hard (Y) aluminum alloy, all three of which have the theme word aluminum alloy (L). For example, QSn represents a class of brass where the main added element is tin (Sn); QAL9-4 represents brass containing aluminum (AL), with 9% aluminum in the composition and other added elements at 4%. The theme word for both these alloys is bronze (Q). Therefore, the product code is represented by a combination of Chinese pinyin letters, chemical element symbols, and Arabic numerals as specified by the standard (GB340-78).
The state, processing method, and characteristic codes of non-ferrous metal casting and alloy products are indicated by specified Chinese pinyin letters, such as R (hot) for hot working, C (quench) for quenching, B (not) for not being coated with aluminum, X (fine) for fine particles, etc. However, there are some exceptions, such as O (perfect) for superior surface quality.
§2 Copper and Copper Alloys
I. Pure Copper
Pure copper is a rose-red metal that appears purple when an oxide copper film forms on its surface, hence industrial pure copper is often referred to as purple copper or electrolytic copper. Its density is 8-9g/cm3, and its melting point is 1083°C. Pure copper has excellent electrical conductivity and is widely used in the manufacture of wires, cables, and brushes; it also has good thermal conductivity and is commonly used in magnetic instruments and meters that need to prevent magnetic interference, such as compasses and aviation instruments. It has extremely good plasticity, making it easy to process through hot pressing and cold pressure processing, producing copper materials such as tubes, rods, wires, strips, bands, plates, and foils. Pure copper products come in two types: smelting products and processed products.
II. Copper Alloys
(1) Brass
Brass is an alloy of copper and zinc. The simplest brass is a binary alloy of copper-zinc, called simple brass or ordinary brass. Changing the zinc content in brass can yield brass with different mechanical properties. The higher the zinc content in brass, the higher its strength, but its plasticity decreases slightly. Industrially used brass contains no more than 45% zinc; any higher zinc content would result in brittleness, degrading the alloy's performance.
To improve certain properties of brass, adding other alloying elements to unary brass results in special brass. Commonly used alloying elements include silicon, aluminum, tin, lead, manganese, iron, and nickel. Adding aluminum to brass improves its yield strength and corrosion resistance while slightly reducing its plasticity. Brass containing less than 4% aluminum has good overall processing and casting properties. Adding 1% tin to brass significantly enhances its resistance to seawater and marine atmospheric corrosion, thus it is called "naval brass." Tin also improves the machinability of brass. Adding lead to brass mainly aims to enhance its machinability and wear resistance; lead has little effect on the strength of brass. Manganese brass has good mechanical properties, thermal stability, and corrosion resistance; adding aluminum to manganese brass can further improve its properties, yielding castings with smooth surfaces. Brass can be divided into two categories: casting and pressure processing products. Common chemical compositions of processed brass.
(2) Bronze
Bronze is one of the earliest alloys historically applied, originally referring to copper-tin alloys. Due to its bluish-gray color, it is called bronze. To improve the technological and mechanical properties of the alloy, most bronzes also contain other alloying elements such as lead, zinc, phosphorus, etc. Since tin is a scarce element, many tin-free bronzes are also used in industry, not only because they are cheaper but also because they possess required special properties. Tin-free bronze mainly includes aluminum bronze, beryllium bronze, manganese bronze, silicon bronze, etc. There are also more complex ternary or quaternary bronzes. Now, except for brass and white copper (copper-nickel alloy), all other copper alloys are referred to as bronze.
Tin bronze has high mechanical properties, good corrosion resistance, low friction properties, and good casting properties; it is less sensitive to overheating and gases, has good welding properties, no ferromagnetism, and a small contraction coefficient. Tin bronze has better corrosion resistance in air, seawater, freshwater, and steam than brass. Aluminum bronze has higher mechanical properties, wear resistance, corrosion resistance, cold resistance, heat resistance, no ferromagnetism, good fluidity, no segregation tendency, and can produce dense castings. Adding iron, nickel, and manganese to aluminum bronze can further improve the various properties of the alloy.
Bronze is also divided into two major categories: pressure processing and casting products.
(3) White Copper
Copper-based alloys with nickel as the main additive element appear silvery white, called white copper. Copper-nickel binary alloys are called ordinary white copper, while copper-nickel alloys with additions of manganese, iron, zinc, and aluminum are called complex white copper. Adding nickel to pure copper significantly increases strength, corrosion resistance, electrical resistance, and thermoelectric properties. Industrial white copper is divided into structural white copper and electrical white copper based on performance characteristics and uses, each satisfying various corrosion-resistant and special electrical and thermal properties.
III. Copper Materials
Materials made from pure copper or copper alloys in various shapes, including rods, wires, plates, bands, strips, tubes, foils, etc., are collectively referred to as copper materials. Copper material processing methods include rolling, extrusion, and drawing. In copper materials, plates and strips can be either hot-rolled or cold-rolled; bands and foils are always cold-rolled; tubes and rods are divided into extruded and drawn products; wires are all drawn.
§3 Aluminum and Aluminum Alloys
Aluminum is a lightweight metal with a low density (2.79/Cm3), possessing good strength and plasticity. Aluminum alloys exhibit good strength, with ultra-hard aluminum alloys reaching a strength of up to 600Mpa, and ordinary hard aluminum alloys having tensile strengths of 200-450Mpa. Their specific stiffness far exceeds that of steel, making them widely used in machinery manufacturing. Aluminum's electrical conductivity ranks third, behind silver and copper, and it is used to make various conductors. Aluminum has good thermal conductivity and can be used as various heat dissipation materials. Aluminum also has good corrosion resistance and plasticity, suitable for various pressure processing.
Aluminum alloys can be classified by processing methods into deformable aluminum alloys and casting aluminum alloys. Deformable aluminum alloys are further divided into non-heat treatable strengthening type aluminum alloys and heat treatable strengthening type aluminum alloys. Non-heat treatable strengthening type aluminum alloys cannot improve mechanical properties through heat treatment and can only achieve strengthening through cold working deformation. They mainly include high-purity aluminum, industrial high-purity aluminum, industrial pure aluminum, and rust-proof aluminum. Heat treatable strengthening type aluminum alloys can improve mechanical properties through quenching and aging heat treatments and are divided into hard aluminum, forged aluminum, ultra-hard aluminum, and special aluminum alloys.
Aluminum alloys can achieve good mechanical properties, physical properties, and corrosion resistance through heat treatment.
Casting aluminum alloys can be classified by chemical composition into aluminum-silicon alloys, aluminum-copper alloys, aluminum-magnesium alloys, and aluminum-zinc alloys.
I. Pure Aluminum Products
Pure aluminum is divided into two categories: smelting products and pressure processing products. The former is represented by the chemical composition Al, and the latter is indicated by the Chinese pinyin LG (aluminum, industrial use).
II. Pressure Processing Aluminum Alloys
Pressure processing aluminum alloy products are divided into seven categories: rust-proof (LF), hard (LY), forging (LD), superhard (LC), cladding (LB), special (LT), and brazing (LQ). The common states of aluminum alloy materials are annealing (M slow fire), hardening (Y), and hot rolling (R).
III. Aluminum Materials
Materials processed from aluminum and aluminum alloys into specific shapes are collectively referred to as aluminum materials, including plates, bands, foils, tubes, rods, wires, and profiles.
IV. Casting Aluminum Alloys
Casting aluminum alloys (ZL) are divided into four categories based on the main elements silicon, copper, magnesium, and zinc in the composition, with code numbers 100, 200, 300, and 400 respectively.
V. High-Strength Aluminum Alloys
High-strength aluminum alloys refer to those with tensile strength greater than 480MPa, mainly including hard aluminum alloys, superhard aluminum alloys, and casting alloys in the category of pressure processing aluminum alloys.
Source: Non-ferrous Metal Casting Professional Service Network http://www.zhongshengweiye.com.cn