Cast iron – fluidity
Sewer covers are an inconspicuous part of our daily environment, and few people pay attention to them. The reason why cast iron has such a large number and wide range of uses is mainly due to its excellent fluidity and its ease of pouring into various complex shapes. Cast iron is actually the name given to a mixture of elements including carbon, silicon, and iron. The higher the carbon content, the better its flow characteristics during pouring. Carbon occurs here in the form of graphite and iron carbide.
The presence of graphite in cast iron gives sewer covers excellent wear resistance. Rust usually only appears on the top layer, so it is usually polished off. Even so, there are still special measures to prevent rust during the pouring process, that is, a layer of asphalt coating is applied to the surface of the casting. The asphalt penetrates into the pores on the surface of the cast iron to prevent rust. The traditional process of producing sand casting materials is now used by many designers in other newer and more interesting fields.
Material properties: excellent fluidity, low cost, good wear resistance, low solidification shrinkage, very brittle, high compressive strength, good machinability.
Typical uses: Cast iron has been used for hundreds of years in construction, bridges, engineering components, homes, and kitchen appliances.
Stainless steel – stainless love
Stainless steel is an alloy made by incorporating chromium, nickel and other metal elements into steel. Its rust-free property comes from the chromium component in the alloy. Chromium forms a strong, self-healing chromium oxide film on the surface of the alloy. This film is invisible to our naked eyes. The ratio of stainless steel to nickel we usually mention is generally 18:10. The word “stainless steel” does not simply refer to one kind of stainless steel, but refers to more than one hundred industrial stainless steels, each of which is developed to have good performance in its specific application field.
At the beginning of the 20th century, stainless steel was introduced into the field of product design. Designers developed many new products around its toughness and corrosion resistance, covering many areas that had never been touched before. This series of design attempts is very revolutionary: for example, equipment that can be reused after sterilization appears in the medical industry for the first time.
Stainless steel is divided into four main types: austenite, ferrite, ferrite-austenite (composite), and martensite. The stainless steel used in household products is basically austenitic.
Material properties: health care, anti-corrosion, fine surface treatment possible, high rigidity, can be formed by various processing techniques, difficult to cold process.
Typical uses: Among commonly used primary color stainless steels, austenitic stainless steel is the most suitable coloring material, which can obtain satisfactory color appearance and shape. Austenitic stainless steel is mainly used in decorative building materials, household products, industrial pipes and building structures; martensitic stainless steel is mainly used to make knives and turbine blades; ferritic stainless steel is anti-corrosive and is mainly used in durable washing machines and Among boiler parts, composite stainless steel has stronger anti-corrosion properties, so it is often used in corrosive environments.
Zinc – 730 lbs in a lifetime
Zinc, shiny silver and slightly bluish-gray, is the third most widely used non-ferrous metal after aluminum and copper. A statistic from the U.S. Bureau of Mines shows that an average person consumes a total of 331 kilograms of zinc in their lifetime. Zinc has a very low melting point, so it is also an ideal casting material
Zinc castings are very common in our daily lives: materials under the surface of door handles, faucets, electronic components, etc. Zinc has extremely high anti-corrosion properties. This characteristic enables it to have another most basic function, namely As a surface coating material for steel. In addition to the above functions, zinc is also an alloy material used together with copper to synthesize brass. Its corrosion resistance doesn’t just apply to steel surface coatings – it also helps strengthen our immune systems.
Material properties: health care, anti-corrosion, excellent castability, excellent anti-corrosion, high strength, high hardness, cheap raw materials, low melting point, creep resistance, easy to form alloys with other metals, health-care properties, at room temperature Fragile and ductile at around 100 degrees Celsius.
Typical uses: electronic product components. Zinc is one of the alloying materials that forms bronze. Zinc also has hygienic and anti-corrosion properties. In addition, zinc is used in roofing materials, photo engraving plates, mobile phone antennas and shutter mechanisms in cameras.
Aluminum (AL) – a modern material
Compared with gold, which has a history of 9,000 years of use, aluminum, a white metal with a slight bluish light, can really only be regarded as a baby among metal materials. Aluminum was introduced and named in the early 18th century. Unlike other metallic elements, aluminum does not exist in nature as a direct metallic element, but is extracted from bauxite containing 50% alumina (also known as alumina). Aluminum, which exists in this form in minerals, is also one of the most abundant metallic elements on our planet.
When aluminum first appeared, it was not immediately used in people’s lives. Later, a number of new products targeting its unique functions and characteristics gradually came out, and this high-tech material gradually gained a wider and wider market. Although the application history of aluminum is relatively short, the output of aluminum products on the market now far exceeds the sum of other non-ferrous metal products.
Material properties: flexible and malleable, easy to make into alloys, high strength-to-weight ratio, excellent corrosion resistance, easy to conduct electricity and heat, recyclable.
Typical uses: vehicle frames, aircraft parts, kitchen utensils, packaging and furniture. Aluminum is also often used to reinforce some large building structures, such as the Cupid statue in London’s Piccadilly Circus and the top of the Chrysler Automotive Building in New York. Aluminum reinforcement materials have been used.
Magnesium alloy – ultra-thin aesthetic design
Magnesium is an extremely important non-ferrous metal. It is lighter than aluminum and can form high-strength alloys with other metals. Magnesium alloys have light specific gravity, high specific strength and specific stiffness, good thermal and electrical conductivity, and good damping reduction properties. It has the advantages of shock and electromagnetic shielding performance, easy processing and molding, and easy recycling. However, for a long time, due to high price and technical limitations, magnesium and magnesium alloys have only been used in a small amount in aviation, aerospace and military industries, so they are called “noble metals”. Today, magnesium is the third largest metal engineering material after steel and aluminum, and is widely used in aerospace, automobiles, electronics, mobile communications, metallurgy and other fields. It can be expected that magnesium metal will become even more important in the future due to the increase in the production costs of other structural metals.
The proportion of magnesium alloy is 68% of aluminum alloy, 27% of zinc alloy, and 23% of steel. It is commonly used in automobile parts, 3C product casings, building materials, etc. Most ultra-thin laptops and mobile phone casings are made of magnesium alloy. Since the last century, humans have still had an indelible love for metal texture and luster. Although plastic products can have a metal-like appearance, their luster, hardness, temperature, and texture are still different from metals. As a new type of metal raw material, magnesium alloy gives people the feeling of high-tech products.
The corrosion resistance of magnesium alloy is 8 times that of carbon steel, 4 times that of aluminum alloy, and more than 10 times that of plastic. Its anti-corrosion ability is the best among alloys. Commonly used magnesium alloys are non-flammable and are especially used in automobile and motorcycle parts and building materials to avoid instantaneous combustion. Magnesium ranks eighth in terms of reserves in the earth’s crust. Most of the magnesium raw materials are extracted from seawater, so its resources are stable and sufficient.
Material properties: lightweight structure, high rigidity and impact resistance, excellent corrosion resistance, good thermal conductivity and electromagnetic shielding, good non-flammability, poor heat resistance, easy to recycle.
Copper – Man’s Partner
Copper is simply an incredibly versatile metal that is so closely related to our lives. Many of mankind’s early tools and weapons were made of copper. Its Latin name “cuprum” originated from a place called Cyprus, an island rich in copper resources. People used the abbreviation Cu of the island’s name to name this metal material, so copper got its current code name.
Copper plays a very important role in modern society: it is widely used in building structures as a carrier for transmitting electricity. In addition, it has been used as a raw material for body decoration by people of many different cultural backgrounds for thousands of years. . This malleable, orange-red metal has evolved with us all the way from its humble beginnings in decoding transmissions to its critical role in complex modern communications applications. Copper is an excellent electrical conductor, its electrical conductivity is second only to silver. From the perspective of the time history of people using metal materials, copper is the oldest metal used by humans after gold. This is largely because copper is easy to mine and relatively easy to separate from copper.
Material properties: good corrosion resistance, excellent thermal conductivity, electrical conductivity, hardness, flexibility, ductility, unique effect after polishing.
Typical uses: wires, engine coils, printed circuits, roofing materials, pipe materials, heating materials, jewelry, cookware. It is also one of the main alloy components used in making bronze.
Chrome – a high-gloss finish
The most common form of chromium is as an alloying element used in stainless steel to enhance the hardness of stainless steel. Chrome plating processes are generally divided into three types: decorative plating, hard chrome plating, and black chrome plating. Chromium plating is widely used in the engineering field. Decorative chromium plating is usually plated on the outside of the nickel layer as the top layer. The plating has a delicate and mirror-like polishing effect. As a decorative post-processing step, the thickness of the chrome plating is only 0.006 mm. When planning to use chromium plating process, the dangers of this process must be fully considered. In the past ten years, the trend of replacing hexavalent decorative chromium water by trivalent chromium water has become increasingly obvious, because the former is very carcinogenic, while the latter is considered to be relatively less toxic.
Material characteristics: very high smoothness, excellent anti-corrosion performance, hard and durable, easy to clean, low friction coefficient.
Typical uses: Decorative chrome plating is the plating material for many automotive components, including door handles and bumpers. In addition, chromium is also used in bicycle parts, bathroom faucets, furniture, kitchen utensils, tableware, etc. Hard chrome plating is used more in industrial fields, including random memories in job control blocks, jet engine components, plastic molds, and shock absorbers. Black chrome plating is mainly used for musical instrument decoration and solar energy utilization.
Titanium – light and strong
Titanium is a very special metal. It is very light in texture, yet very tough and corrosion-resistant. It maintains its color tone for life at room temperature. The melting point of titanium is similar to that of platinum, so it is often used in aerospace and military precision components. Different colors are produced by adding electric current and chemical treatment. Titanium has excellent resistance to acid and alkali corrosion. Titanium that has been soaked in “Aqua Regia” for several years is still shiny and radiant. If titanium is added to stainless steel, only about one percent is added, which greatly improves the rust resistance.
Titanium has excellent properties such as low density, high temperature resistance, and corrosion resistance. The density of titanium alloy is half that of steel and its strength is similar to steel; titanium is resistant to both high temperature and low temperature. It can maintain high strength in a wide temperature range of -253℃~500℃. These advantages are exactly what space metal is necessary for. Titanium alloy is a good material for making rocket engine casings, artificial satellites and spacecrafts, and is known as “space metal”. Because of these advantages, titanium has become a prominent rare metal since the 1950s.
