Mechanical properties of steel introduced 1. Yield point (ss) tensile steel or specimen, when the stress exceeds the elastic limit, even if the stress is no longer increasing, while steel or continue to sample the apparent plastic deformation , called this phenomenon, yield, yield phenomena arevolution when the yield point shall be the minimum stress. set Ps yield point s Office for the external coerces into, Fo basal area for the sample, then the yield point ss = Ps / Fo ( MPa), MPa called MPa is equal to N (N) / mm2, (MPa = 106Pa, Pa: Pascal = N/m2) 2. yield strength (s0.2) yield some metallic materials point very apparent, the arduousies in Celiang on You, so to measure the material's yield characteristics of the residual plastic deformation Guiding produce Yongjiu Dengyuyiding value (typically 0.2% original length) when stress, or simply known as Tiao Jian Qiang Du yield strength yield s0.2. 3. tensile strength (sb) material in the drawing process, from start to fracture when the maximum stress reached. It is said that the ability of steel to resist fracture size. and tensile intensity of the corresponding still compressive strength, flexural strength. set Pb reached before the material is pulled off the massivegest rally, Fo-fragmental area for the sample, then the tensile strength sb = Pb / Fo (MPa). 4. elongation rate (ds) material pulled up the rear, the plastic elongation of the length and the length of the birthal sample is called elongation size or the percentage of elongation. 5. yield ratio (ss / sb) steel yield point (yield strength) and tensile strength ratio, known as the yield ratio. the greater the yield ratio, the higher the relicapacity of structural components, the general carbon steel yield ratio of 0.6 -0.65, low-alloy structural steel is 0.65-0.75 alloy structural steel is 0.84-0.86. 6. hardness that material hardness against a hard object pressed into the surface of ability. It is an crucial performance index of metal materials for 1. generally higher hardness, better wear resistance. commonly used indicators Brinell hardness, Rockwell hardness and Vickers hardness. ⑴ Brinell hardness (HB) to a certain load (usually 3000kg ) to a certain size (diameter usually 10mm) hardened steel ball pressed into the surface, maintaining a period of time to set, the load is the ratio of indentation area, namely, Brinell hardness (HB), in units of kilograms of compel / mm2 (N/mm2). ⑵ Rockwell hardness (HR) when HB> 450 or the sample is too minuscule and can not be replaced by Brinell hardness test Rockwell hardness measurement. It is a support angle of 120.'s diamond cone or steel ball 1.59,3.18 mm diameter, to a certain load onto the measured surface, the depth obtained by the indentation hardness of the material. According to the different hardness tests at three levels different scale to that: HRA: a diamond cone with 60kg load and indentation hardness obtained device for high hardness materials (such as carbide, etc.). HRB: is the use of 100kg load and diameter of 1.58mm hardened steel ball, the hardness obtained for the lower hardness of the material (such as annealed steel, cast iron, etc.). HRC: a diamond cone with 150kg load and pressure into the device sought by hardness, high hardness materials used (such as hardened steel, etc.). ⑶ Vickers hardness (HV) to 120kg of load and support within the angle of 136.'s diamond cone pressed into the square indentation device materials surface, with material divided by the surface area of indentation load value pit, that is, Vickers hardness (HV) steel product knowledge (1 )---- Steel Section Steel Category Category 1, ferrous and nonferrous metals 1, black metal is iron and iron alloy. such as steel, pig iron, ferroalloy, iron and so on. steel and pig iron are iron-based, carbon- principal alloy elements added, collectively known as the iron carbon alloy. refers to the iron ore into pig iron in the smelting furnace formed products, mainly used for steel making and manufacturing of castings. the cast iron on the melting Melting cupola, which are cast iron (liquid, carbon is higher than 2.11% of the iron carbon alloy), the liquid cast iron into the casting, this cast iron is called cast iron. alloy is made of iron and silicon, manganese, chromium, titanium and other elements of the alloy, iron alloy is one of steelmaking raw materials, made the steel in the steel oxygen additive agents and alloying elements used. carbon content of less than 2.11% of the iron carbon steel alloy called , the steel making pig iron into steel melting furnace by a certain process, which are steel. steel products, steel ingot, actet and cast all kinds of steel castings and so on directly. usually about the steel, generally refers to rolling abnormale of various steel products steel. 2, non-ferrous metals called non-ferrous metals, ferrous metals than that outside the metals and alloys, such as copper, tin, lead, zinc, aluminum and brass, bronze, aluminum and bearing alloys. Also in the business also uses chrome, nickel, manganese, molybdenum, cobalt, vanadium, tungsten, titanium, alloys of these metals is mainly used for attachment to improve the performance of metal, including tungsten, titanium, molybdenum and many other tools used for the production of carbide. These are known as non-ferrous metal industry, in addition to precious metals: platinum, gold, silver and rare metals, including radioactive uranium, radium and so on. Second, the classification of steel major elements except iron steel, carbon, there are silicon, manganese, sulfur and phosphorus. the positionification of a wide range of steel, the main method have the following seven: 1, by Quality Classification (1) mundane steel (Pl0.045%, Sl0.050%) (2) high quality steel (P, S are l0.035%) (3) High quality steel ( Pl0.035%, Sl0.030%) 2, classified by chemical composition (1) Carbon steel: a. low carbon steel (Cl0.25%); b. medium carbon steel ( Cl0.25 ~ 0.60%); c. High carbon steel (Cl0.60%). (2) Steel: a. low-alloy steel (the total content of alloying elements l5%); b. in the alloy steel (the total content of alloying elements> 5 ~ 10%); c. high-alloy steel (alloy element contents> 10%). 3, by forming methods Category: (1) forged steel; ( 2) steel; (3) hot-rolled steel; (4) cold-drawn steel. 4, according to the microstructure Category (1) annealed state: a. sub-eutectoid steel (ferrite pearl body); b. eutectoid steel (pearlite); c. hypereutectoid steel (pearlite + cementite); d. ledeburite steel (pearlite + cementite). (2) is Fire state: a. pearlite steel; b. bainitic steel; c. martensitic steel; d. austenitic steel. (3) no phase deviate or part of the phase transition of 5 by use classification (1) construction and engineering steel: a. ordinary carbon structural steel; b. low alloy steel; c. steel. (2) structural steel a. Mechanical manufacture of steel: (a) quenched and tempered structural steel; (b) hardening structural steel: including case-hardened steel, ammonia permeability of steel, surface hardening steel; (c) easy to cut structural steel; (d) cold forming steel : including cold stamping steel, cold heading steel. b. spring steel c. bearing steel (3) tool steel: a. carbon tool steel; b. alloy tool steel; c. high-speed tool steel. (4) special properties of steel: a. stainless steel acid; b. heat-resistant steel: steel, including oxidation, heat resistant steel, valve steel; c. electric steel; d. wear steel; e. cold steel; f. electrical steel. (5) mm, such as specialized steel bridge steel, ship steel, boiler steel, pressure vessel steel, steel and other farm machinery. 6, overall classification (1) ordindiffer steel a. carbon steel: (a) Q195; (b) Q215 (A, B); (c) Q235 (A, B, C); ( d) Q255 (A, B); (e) Q275. b. low alloy steel c. specific uses ordinary structural steel (2) high quality steel (including high quality steel) a. Structural Steel: (a) high-quality carbon structural steel; (b) alloy steel; (c) spring steel; (d) easy to cut steel; (e) bearing steel; (f) for a particular purpose of quality structural steel. b. tool steel: (a) carbon tool steel; (b) alloy tool steel; (c) high-speed tool steel. c. special properties of steel: (a) acid-resistant stainless steel; (b) heat-resistant steel; (c) electric steel; (d) electrical steel; (e) high wear-resistant manganese steel. 7, by smelting method of classification (1) by seed a furnace . BOF steel: (a) acid converter steel; (b) basic converter steel. or (a) bottom blown converter steel; (b) side-blown converter steel; (c) support the blown converter steel. b. Furnace steel: (a) electric arc furnace steel; (b) electroslag furnace steel; (c) induction furnace steel; (d) consumable vacuum furnace steel; (e) electron-beam furnace steel. (2) by oxygen levels and the system of sub- a. pouring boiling steel; b. semi-killed steel; c. killed steel; d. special killed steel. steel body of knowledge (2) II, said China's steel method 1, China Steel said the method outlined steel grade steel for fleeting, is a concrete and steel for each product to take the name of the people to understand the steel is a universal language. China's steel, said method According to the standard \method of combining said. that is: ① steel chemical elements in the interstateal chemical symbols used, such as Si, Mn, Crhh so. mixed infrequent earth elements with the \> ② product name, purpose, smelting and casting methods, ubiquitously used abbreviation of Pinyin letters, ③ the main chemical elements in steel content (%) using Arabic numerals. that product name using Chinese phonetic alphabet , uses, properties and process methods, usually from the representative product name, select the first letter of the Pinyin. When used with another product repeated letters, the letters could be replaced by the second or third letter, or both Select the first two characters in the alphabet. no Chinese characters and Pinyin can be used, the use of symbols for the letters. Second, China Steel said the method of Classification Description 1, carbon prime structural steel and low alloy high strength structural steel grades that step more common steel and is usually divided into two major categories of special steel. brands that method, the steel yield point or yield strength of the Chinese phonetic alphabet, yield point or yield strength value, quality and grade of steel and other components, as well as the steel oxygen level increases are actually 4 parts. ① general structural steel with yield point representative of the phonetic alphabet \units of MPa) and Table 1 provides the quality grade (A, B, C, D, E), deoxy method (F, b, Z, TZ) symbols, composed of grades in order. For example: carbon structural steel grades expressed as: Q235AF, Q235BZ; low alloy high strength structural steel grades expressed as: Q345C, Q345D. Q235BZ said the yield point value g235MPa, quality level of sedation for the B grade carbon steel. Q235 and Q345 which Two steel grades are the most typical engineering, production and use of the largest, most versatile grade. The two brands almost all countries in the world. carbon structural steel grade dissertation, killed steel symbol \and special killed steel symbol \strength structural steel have killed steel and special killed steel, but the grade oxygen tail method without express written symbols. ② special structural steel yield point of steel is quintessentially used on behalf of the symbol \required use of symbols representative of said products, such as: pressure vessel steel grade is expressed as \grade. ③ needed, common high-strength low-alloy structural steel grades can also be used by two Arabic numerals (that the average carbon content, have much of a few dollars) and the chemical element symbols, in order that; special low-alloy high-strength structural steel grades can also be used by two Arabic numerals (that the average carbon content, have much of a few dollars) and the chemical element symbols, as well as representatives of products specified in Table 1 uses the symbol, according to the order said. 2, high-quality carbon structural steel and quality carbon steel grades that way quality carbon structural steel with two Arabic numerals (in the extreme that the average carbon content of a few dollars) or Arabic numbers and element symbols, Table 1 to form the symbols prescribed grades. ① boiling steel and semi-killed steel, the rear were added in Grade symbol \expressed as \: The average carbon content of 0.45% of the killed steel, the grade is expressed as \symbol. For example: The average carbon content of 0.50%, manganese content was 0.70% to 1.00% of the steel, the grade is expressed as \030%), added symbols in Grade \Steel (Sl0.020%, Pl0.025%), in Grade added symbol \ high-quality carbon steel grades that methods and quality carbon structural steel grades that the same way (65,70,85,65 Mn steel in GB/T1222 and GB / T 699 also exist between the two standards). 3, alloy steel and spring steel alloy, said method ① grade alloy steel grades using Arabic numerals and standard chemical element symbols. with the average carbon content of the two Arabic numerals (in the extreme a few dollars), on the head grade. alloying elements, said avenue: the average content of less than 1.50%, the grade, distinctive; marked elements, generally do not indicate the content; average alloy content of 1.50% and 2.49%, 2.50 % ~ 3.49%, 3.50% ~ 4.49%, 4.50% ~ 5.49%, hh, the elements in the alloy after the corresponding written 2,3,4,5 hh. example: carbon, chromium, manganese, silicon, the average content were 0.30%, 0.95%, 0.85%, 1.05% of the alloy structural steel, when the S, P contents were l0.035%, its grade is expressed as \P content l0.025%), tail plus sign in Grade \tail plus symbol \The 30CrMnSi steel, steel that is ML30CrMnSi. ② grade alloy spring steel and alloy steel representation of the same. example: carbon, silicon, manganese, the average content of 0.60%, 1.75%, 0.75% The spring steel, the grade is expressed as \> free cutting steel using standard chemical element symbols, the symbols specified in Table 1 and Arabic numerals. Arabic, said the average carbon content (in a few extreme of total). ① Sulfur cutting steel and modeing of sulfur, phosphorus Easy cutting steel, the symbol \higher manganese content increases in sulfur or add sulfur, phosphorus free cutting steel in the symbol \The free cutting steel, the rank is expressed as \; Y15Pb \cutting non-quenched and tempered structural steel and boiling forging machines with non-mechanical structure of quenched steel, station representation of other alloy steel with the same content. For example: \representation tool steel into carbon tool steel, alloy tool steel and high-speed tool steel categories. ① carbon tool steel using standard chemical element symbols, Table 1 provides the symbols and Arabic numerals. Arabic that the average carbon content (in thousandths of dollars). a. normal manganese content of carbon tool steel, tool steel symbol in the \Carbon tool steel, the grade is expressed as \\, said the way high-speed tool steel grades and alloy steel grades that the same way. alloying elements required by the standard symbols and Arabic numerals, but generally do not indicate the average number of carbon content, such as: The average carbon content of 1.60%, chromium , molybdenum, vanadium content was 11.75%, 0.50%, 0.22% of the alloy tool steel, the grade is expressed as \, 5.00%, 4.00%, 2.00% of the high-speed tool steel, the grade is expressed as \a few parts per meter). For example: The average carbon content of 0.80%, manganese content was 0.95%, 0.45% silicon content of alloy tool steel, the grade is expressed as \chromium content