One of the greatest discoveries of the 19th century was how to make steel. This metal is a mixture of iron and a controlled amount of carbon. It was easy to produce and very hard. Engineers used steel extensively in many of the new machines produced in the 19th century. But steel had one big problem: it rusted easily. Tools that were subjected to constant hammering and exposure to moisture would quickly corrode. Over time, scientists tried to find a way around this problem by fusing other metals with steel to form various rust-resistant alloys.
On the eve of World War I, the choking smell of gunpowder has filled the land of Europe, the British government for the needs of the war, decided to develop a wear-resistant, high-temperature-resistant gun chamber steel
to improve weapons. So, they will smelt steel task to the metallurgist Henry. Harry Brearley, a metallurgist.
We know that smelting steel needs to be added to a certain chemical element, based on the proportion of its content, in order to obtain a variety of hardness, strength, toughness, plasticity and wear-resistant, heat-resistant, acid-resistant and other mechanical properties, physical properties and chemical properties of the metal materials that people need. Brier led assistants, smelting tests for a variety of formulas, but the steel produced by the test test failed to meet the requirements of the provisions of the manufacture of gun barrel materials. Brier is not discouraged, re-examine and amend the ratio of added chemical elements, and continue to manufacture the steel smelting for the gun barrel.
Breier's smelting experiments did not go well, failing again and again, and they threw the non-compliant steel into the open corner of the test site. With the passage of time, the waste steel is piled higher and higher, into a small mountain of waste steel through the sun and rain, become rusty. One day, the test personnel decided to clean up this batch of abandoned test pieces. In the handling, people found in this pile of corroded steel pieces but there are a few pieces of scrap steel shining. Why these pieces of steel did not appear rust? Brier check up after repeated observation and inspection, but also feel surprised and puzzled. In order to unravel the mystery of this strange thing, he decided to research on these pieces of strange steel.
Breier carefully recalled, and repeatedly access to the steelmaking test records, but too many tests have been unable to trace the exact smelting time and formula of these pieces of steel. In order to find out its chemical element composition content, Brier decided to carry out laboratory tests on it. After testing and analyzing the results of this is a piece of iron-chromium alloy, which contains carbon 0.24%, chromium 12.8%. Brier was overjoyed, he continued to study, water, acid, alkali and other corrosive tests. The results proved that he had produced in the smelting test of iron and chromium alloy but has any time are not easy to rust characteristics, 1912 stainless steel was discovered.
Scientific exploration is full of hard and tedious work, but also full of fun and serendipity. People say that stainless steel is a metallurgist Briere crooked invention, is the development of the metal material of the rifle bore steel and get out of the by-products. 1915, Briere stainless steel discovery results in the United States patented; 1916 the results of the British patent. At this time, Brier and Mosler partnership founded a production of stainless steel tableware factory, the scientific and technological achievements into productivity. Because of the novel stainless steel tableware popular with people and popular in Europe, and later spread around the world. As a result, Brier also won a high reputation, he is honored as the father of stainless steel.
However, Brier is not the first discoverer of stainless steel. in the early 20th century, France, Gueye and Porouz two engineers have found that iron doped with chromium after the metal has a bright and corrosion resistant, because at that time, do not know this alloy has a use, it will be recklessly thrown away. 1912, the United States of America, Hermes also came up with a stainless steel. The same period of German metallurgical experts Schuttler and Mauer also found in the smelting of chromium, nickel can be made into steel will not rust. Their discovery is almost the same starting line with the British Brill, but the observation of the strange phenomenon, they did not ask a why? But in the step into the scientific door to continue the research stopped in front of the footsteps, and thus with the first discovery of stainless steel honor laurels and to develop and utilize the huge economic benefits of the brush.
In metal materials science, stainless steel is a special performance steel, it is mainly used in special environments as a product component or work parts. So, where is the mystery of stainless steel? The original has special physical and chemical properties of stainless steel, in the smelting of alloying elements, such as molybdenum, titanium, copper, drilling, nickel, niobium, manganese and carbon and other elements, but the chromium content of the chemical composition must ensure that the 12.0% - 19.0% range. According to the alloying elements added, stainless steel is divided into chromium stainless steel and nickel-chromium stainless steel; in accordance with the characteristics of the stainless steel metallurgical organization can be divided into martensitic, ferrite, austenitic and precipitation hardening type. With the rapid development of science and technology, so far, the type of stainless steel has reached more than 100 kinds of grades, for example, not only has the ability to resist rust and corrosion in the air, but also has the function of acid resistance, this kind of stainless steel is called acid-resistant steel.
Because all stainless steel is composed of the elemental composition of the content of the decision, so not any kind of stainless steel can resist a variety of media attack corrosion: usually referred to as stainless steel can only defend against atmospheric exposure corrosion (temperature, humidity, sunlight, rainfall and atmospheric dirt, etc., corrosion), and over time there will be a surface discoloration, and even appear rust stains. But these flaws can not erase the glory of stainless steel performance, but also can not shake the status of being laid a broad range of uses. People called stainless steel, it is the 20th century to change the course of human civilization, a major scientific discovery.
And later other researchers found that in order to enhance the ductility and formability of stainless steel, stainless steel are added nickel to achieve this effect. And in order to reduce the cost of researchers and then get the standard stainless steel its chromium content can be less than the original 14% but not less than 10.5%. Finally, the study of its quality and purity, surface brightness good # 304 (along the Japanese stainless steel product number) is 18-10, 18 that is to say that this stainless steel containing chromium 18%, 10 that is to say that this stainless steel containing nickel 10%, and the remaining 72% that is the content of iron.
The invention of stainless steel is a major achievement in the history of metallurgy in the world.
In the early twentieth century, Gier (L.B. Guillet) in 1904 1906 and Portevan (A.M. Portevin) in France in 1909 1911; Giesen (W. Giesen) in 1907 1909 in the United Kingdom respectively, discovered the resistance of Fe Cr and Fe Cr-Ni alloys for their corrosion resistance. Monnartz (P. Monnartz) put forward many ideas of stainlessness and passivation theory in Germany in 1908-1911. The inventors of stainless steel for industrial use are: Brierley (H. Brearly) 1912 1913 in the United Kingdom developed a martensitic stainless steel containing Cr12% 13%; Danzizen (C. Dantsizen) 1911 1914 in the United States developed a ferritic stainless steel containing Cr14% 16%, C 0.07% 0.15%; Maurer (E. Maurer (E. Maurer) and Strauss (B. Strauss) 1912 1914 in Germany developed austenitic stainless steel containing C & lt; 1%, Cr 15% 40%, Ni & lt; 20% In 1929, Strauss (B. Strauss) obtained a patent for low-carbon 18-8 (Cr-18%, Ni-8%) stainless steel. In order to solve the 18-8 steel sensitized state intergranular corrosion, in 1931 Germany's Houdreuot (E. Houdreuot) invented the 18-8 stainless steel containing Ti (equivalent to the current 1Cr18Ni9Ti or AISI 321). Almost at the same time, the Unieux Laboratory in France found that the austenitic stainless steel containing ferrite, the steel's resistance to intergranular corrosion will be significantly improved, and thus developed ? +? In 1946, the U.S. Smith Ettar (R. Smithetal) developed a martensitic precipitation hardening stainless steel 17-4PH; followed by both high-strength and cold forming semi-austenitic precipitation hardening stainless steel 17-7PH and PH15-7Mo and other phases came out. So far, the stainless steel family in the main steel categories, namely martensite, ferritic, austenitic, ? +? Duplex and precipitation hardening type stainless steel species will be basically complete, and has continued to the present. Of course, 40-50 years, section Ni Cr-Mn-N and Cr-Mn-Ni-N stainless steel, ultra-low carbon (C? 0.03%) austenitic stainless steel; 60 years, ? :? Nearly 1? +? Duplex stainless steel and C + N ?150ppm high-purity ferritic stainless steel and martensitic aging stainless steel, although also belongs to the stainless steel field of major advances, but these new steel still belongs to the aforementioned five categories of stainless steel in essence, is only specific to certain types of steel in the new development of the steel. Stainless steel, in addition to C, Cr, Ni and other elements, according to the performance requirements of different uses, further Mo, Cu, Si, N, Mn, Nb, Ti and other elements of alloying or further reducing the steel C, Si, Mn, S, P and other elements, and developed many new steel. For example, in order to solve the chloride pitting corrosion, crevice corrosion with high purity, high chromium and molybdenum ferritic stainless steel 00Cr25Ni4Mo4,,00Cr29Mo4Ni2, 00Cr30Mo2 and high Mo containing N Cr-Ni dual-phase stainless steel 00Cr25Ni7Mo3N, 00Cr25Ni7Mo3CuN, etc.; in order to improve the strength and resistance of the low-carbon, ultra-low carbon Cr-Ni In order to improve the strength and corrosion resistance of low carbon, ultra-low carbon Cr-Ni austenitic stainless steel and the emergence of nitrogen-controlled stainless steel; in order to improve the Cr-Ni austenitic stainless steel resistance to local corrosion and inhibit the precipitation of intermetallic phases in the steel and the development of high-Cr, Mo and nitrogen super austenitic stainless steels, such as 00Cr25Ni20Mo6CuN, 00Cr24Ni22Mo7Mn3CuN; in order to withstand the fuming of nitric acid, as well as resistance to concentrated sulfuric acid (93% 98%) and the development of high silicon (Si 6%) stainless steel. In addition, there are a number of specialized stainless steel, such as nuclear grade, nitric acid grade, urea grade, food grade stainless steel and so on. According to statistics, the world has been included in a variety of standards (including factory standards) has more than 100 kinds of grades, and not standardized non-standard grades are more. Nevertheless, the current mass production of advanced industrial countries and widely used stainless steel grades, limited to martensite, ferritic and austenitic class of nearly a dozen grades.
There are more than 100 types of various stainless steels in use today, with varying proportions of chromium, nickel and other metals. All of these steels have unique properties, such as being easy to shape even when cold or being resistant to impact and rust.