Smith makes medical equipment.

As a special material, it has been widely used in modern industrial construction, chemical equipment, medical care, national defense, even spacecraft and cutting-edge technology. So, how was the magical metal material stainless steel born? /kloc-one of the greatest discoveries of the 0/9th century is how to make steel. This metal is a mixture of iron and a certain amount of carbon. It's easy to produce and it's hard. Engineers have widely used steel in many new machines produced in the19th century. But steel has a big problem. It rusts easily. Tools that are repeatedly knocked and wetted will corrode quickly. As time goes by, scientists try to solve this problem by fusing other metals with steel to form various antirust alloys. On the eve of the First World War, the suffocating smell of war gunpowder has filled the land of Europe. For the need of actual combat, the British government decided to develop a kind of gun bore steel with wear resistance and high temperature resistance to improve weapons. So they gave the task of steelmaking to Harry buhrer, a metallurgical expert. We know that iron and steel smelting needs to add a certain chemical element, and according to its content ratio, various metal materials with mechanical properties, physical properties and chemical properties such as hardness, strength, toughness, plasticity, wear resistance, heat resistance and acid resistance can be obtained. Breier led an assistant to carry out smelting tests of various formulas, but the steel produced could not meet the requirements for manufacturing gun bore materials. Undaunted, Breier re-studied and revised the proportion of chemical elements added, and continued to smelt steel for gun bore. Brier's smelting test process was not smooth and failed again and again. They threw all these unqualified steel blocks into the open corner of the proving ground. With the passage of time, the scrap steel piled higher and higher, and became a hill-like scrap steel, which was rusty after exposure to the sun and rain. One day, the tester decided to clean up the abandoned specimens. During the handling process, it was found that several pieces of scrap steel were glowing in this pile of corroded steel parts. Why aren't these steel sheets rusted? After the investigation, Brill repeatedly observed and tested, and he was also puzzled. In order to solve the mystery of this strange thing, he decided to study these strange steel sheets. Breier carefully recalled and repeatedly consulted the steelmaking test records, but the exact smelting time and formula of these steel sheets could not be traced back after too many tests. In order to find out its chemical element content, Brill decided to test it. The test results show that it is an Fe-Cr alloy, containing 0.24% carbon and 0/2.8% chromium/kloc-. Brill was overjoyed. He continued his research and made corrosive tests, such as water, acid and alkali. The results show that the Fe-Cr alloy produced by his smelting test is not easy to rust at any time, and 19 12 stainless steel is found. Scientific exploration is a hard and boring job, but it is also full of interest and contingency. It is said that stainless steel was invented by Breier, a metallurgical expert, and was a by-product of the development of gun bore steel and metal materials. 19 15, Brier's stainless steel discovery was patented in the United States; 19 16 This achievement was granted a British patent. At this time, Breier and Moselle jointly built a factory to produce stainless steel tableware, which transformed scientific and technological achievements into productivity. This novel stainless steel tableware was very popular in Europe and later spread all over the world. Therefore, Brill also won a high reputation. He is known as the father of stainless steel. However, Breier was not the first discoverer of stainless steel. At the beginning of the 20th century, two French engineers, Gayer and Boruz, found that the metal doped with chromium in iron was bright and corrosion-resistant, because they didn't know what this alloy was for, so they threw it away rashly. 19 12 years, Hermes in the United States also made stainless steel. At the same time, German metallurgical experts Shutlaus and Maurer also found that adding chromium and nickel in smelting can make steel that won't rust. Their findings are almost on the same starting line as Brier in Britain, but they didn't ask any questions about the strange phenomena they observed. However, it stopped before stepping into the scientific gate of continuing research, thus passing the honor of discovering stainless steel for the first time and gaining huge economic benefits from its development and utilization. In metal materials science, stainless steel belongs to special performance steel, which is mainly used as product parts or working parts in special environment. So, where is the mystery of stainless steel? For stainless steel with special physical and chemical properties, alloying elements such as molybdenum, titanium, copper, diamond, nickel, niobium, manganese and carbon are added during smelting, but the chemical content of chromium must be kept within the range of 12.0%- 19.0%. According to the added alloying elements, stainless steel is divided into chromium stainless steel and nickel-chromium stainless steel; According to the metallographic characteristics of stainless steel, it can be divided into martensite type, ferrite type, austenite type and precipitation hardening type. With the rapid development of science and technology, the types and brands of stainless steel have exceeded 100. For example, this kind of stainless steel is not only corrosion-resistant in air, but also acid-resistant. This kind of stainless steel is called acid-resistant steel. Because all stainless steels are determined by the content of their constituent elements, not all stainless steels can resist the invasion and corrosion of various media: stainless steels can usually only resist atmospheric exposure corrosion (temperature, humidity, sunlight, rainfall and atmospheric pollutants, etc.). ), the surface will turn red or even rust after a long time. However, these defects cannot obliterate the brilliance of stainless steel performance, nor can they shake its position in a wide range of applications. People call it stainless steel, which is an important scientific discovery that changed the process of human civilization in the 20th century. In the future, other researchers found that in order to enhance the ductility and formability of stainless steel, nickel was added to all stainless steels to achieve this effect. In order to reduce the cost, researchers later obtained standard stainless steel, the chromium content of which can be lower than the original 14% but not lower than 10.5%. Finally, it is found that #304 (following the Japanese stainless steel product number) is 18- 10, 18 means that stainless steel contains 18% chromium, 10 means that stainless steel contains 10% nickel, and the rest. The invention of stainless steel is a great achievement in the world metallurgical history. At the beginning of the 20th century, L.B.Guillet was in France19041906a.m. Portevin was in 1909 19 1. W.Giesen discovered the corrosion resistance of Fe Cr and Fe Cr-Ni alloys in Britain at 1907 1909 respectively. In1908-1911,P.Monnartz put forward many views on German rust and passivation theory. Inventors of industrial stainless steel include: Martensite stainless steel with Cr121913% developed in Britain; In 2004, C. Dantsizen developed ferritic stainless steel containing Cr 14% 16% and C 0.07% 0. 15% in the United States. Maurer (E.Maurer) and Strauss (B. Strauss)19121914 years have developed a system containing C & 1%, chromium 15% 40%, nickel and cobalt. lt； 20% austenitic stainless steel. 1929, B.Strauss obtained the patent of low-carbon stainless steel (Cr- 18%, Ni-8%). In order to solve the sensitized intergranular corrosion of 18-8 steel, in 193 1 year, German E.Houdreuot invented Ti-containing 18-8 stainless steel (equivalent to 1Cr 18Ni9Ti. Almost at the same time, Unieux laboratory in France found that when ferrite is contained in austenitic stainless steel, its intergranular corrosion resistance will be obviously improved, so & gamma; +& amp； Alpha; Duplex stainless steel. 1946, the martensitic precipitation hardening stainless steel17-4ph was developed by R.Smithetal. Subsequently, semi-austenitic precipitation hardening stainless steel 17-7PH and PH 15-7Mo with high strength and cold formability came out one after another. Up to now, the main steels in the stainless steel family, namely martensite, ferrite, austenite,&; Alpha; +& amp； Gamma; Duplex stainless steel and precipitation hardening stainless steel are basically complete and have continued until now. Of course, in the 1940s and 1950s, nickel-saving Cr-Mn-N and Cr-Mn-Ni-N stainless steel, ultra-low carbon (C&L; 0.03%) austenitic stainless steel; In the 1960s,&; Gamma; : & alpha; Close to1&; alpha； +& amp； Gamma; Duplex stainless steel and C+N&; Music; Although the appearance of 150ppm high-purity ferritic stainless steel and maraging stainless steel is also a great progress in the field of stainless steel, these new steel grades still belong to the above five categories of stainless steel in essence, but some steel grades are new developments in specific steel grades. In stainless steel, in addition to C, Cr, Ni and other elements, Mo, Cu, Si, N, Mn, Nb, Ti and other elements are further alloyed or reduced according to the performance requirements of different applications, and many new steel grades are developed. For example, high-purity and high-chromium molybdenum ferritic stainless steels 00Cr25Ni4Mo4, 00Cr29Mo4Ni2, 00Cr30Mo2 and Cr-Ni duplex stainless steels 00Cr25Ni7Mo3N and 00cr25ni7mo3cun with high Mo content to solve chloride pitting corrosion and crevice corrosion; Nitrogen controlled stainless steel seems to improve the strength and corrosion resistance of low carbon and ultra-low carbon chromium-nickel austenitic stainless steel; In order to improve the local corrosion resistance of Cr-Ni austenitic stainless steel and inhibit the precipitation of intermetallic phases in steel, super austenitic stainless steels with high Cr, Mo and N contents were developed, such as 00Cr25Ni20Mo6CuN and 00Cr24Ni22Mo7Mn3CuN. High silicon (Si 6%) stainless steel was developed to resist fuming nitric acid and concentrated sulfuric acid (93% 98%). In addition, there are some special stainless steels, such as nuclear grade, nitric acid grade, urea grade and food grade stainless steel. According to statistics, there are more than 100 brands that have been included in various standards (including factory standards) in the world, and even more non-standard brands have not been accepted. Nevertheless, at present, stainless steel brands produced in large quantities and widely used in advanced industrial countries are limited to nearly a dozen brands such as martensite, ferrite and austenite. There are more than 100 kinds of stainless steel in use now, which contain chromium, nickel and other metals in different proportions. All these steels have unique properties, such as easy forming when cold, or the ability to resist impact and rust.