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螺丝的强度等级(Strength grade of a screw)

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螺丝的强度等级(Strength grade of a screw)螺丝的强度等级(Strength grade of a screw) 螺丝的强度等级(Strength grade of a screw) Strength grade of bolts Steel structure connecting bolts 3.6, 4.6, performance grade 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9 and more than 10 levels, of which 8.8 or more bolt material for lo...

螺丝的强度等级(Strength grade of a screw)
螺丝的强度等级(Strength grade of a screw) 螺丝的强度等级(Strength grade of a screw) Strength grade of bolts Steel structure connecting bolts 3.6, 4.6, performance grade 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9 and more than 10 levels, of which 8.8 or more bolt material for low carbon alloy steel or carbon steel by heat treatment (quenching and tempering), known as the high strength bolts, known as the rest ordinary bolt. There are two parts in the performance grade of bolts. They are the nominal tensile strength of the bolt material and the ratio of the tensile strength. For example, a performance grade 4.6 bolt means "yes": 1. Nominal tensile strength of bolt material reaches 400MPa grade; 2, the bolt strength ratio is 0.6; 3. The nominal yield strength of bolt material is 400 * 0.6=240MPa class, and the performance grade 10.9 is high strength bolt. The material can be reached after heat treatment: 1. Nominal tensile strength of bolt material reaches 1000MPa grade; 2, the bolt strength ratio is 0.9; 3. The nominal yield strength of bolt material is 1000 * 0.9=900MPa class The meaning of the performance grade of a bolt is an international standard. The performance of the bolt of the same performance grade is the same regardless of the material and the place of origin. The performance grade can only be used in the design. Strength class, class 8.8 and 10.9 The shear stress grades of bolts are 8.8GPa and 10.9Gpa 8.8 nominal tensile strength 800N/MM2 nominal yield strength 640N/MM2 The general bolt is expressed with the strength of "X.Y", X*100= tensile strength of this bolt, X*100* (Y/10) = yield strength of this bolt (as specified by the mark: yield strength / tensile strength =Y/10) =============== Class 4.8 Of this bolt Tensile strength: 400MPa The yield strength is 400*8/10=320MPa Desolate Another: stainless steel bolts are usually labeled "A4-70", "A2-70" look, meaning otherwise explained measure There are two main types of one of the world's length measuring unit, a metric unit of measure for the meter (m), cm (CM), mm (mm), is widely used in Europe, China and Japan in Southeast Asia, the other one is British, mainly for units of measurement (inch), a. In our country the old rural, is widely used in the United States, Britain and other European countries. 1, metric measurement: (10 hexadecimal) 1m =100 cm=1000 mm 2, imperial measurement: (8 hexadecimal) 1 inch =8 1 inch =25.4 mm 3/8 British Phi Phi * 25.4 =9.52 3, 1/4 of the following products of designation for its name for size, such as: 4#, 5#, 6#, 7#, 8#, 10#, 12# Thread A thread is a solid outer surface or inner surface of the cross section, there is a uniform spiral line convex shape. According to its structure, characteristics and uses can be divided into three categories: (1) ordinary threads: the teeth are triangular in shape and are used for connecting or fastening parts. The ordinary thread is divided into two kinds of coarse and fine thread according to the pitch, and the connection strength of the fine thread is higher. (two) driving thread: tooth shape has ladder, rectangle, saw shape and triangle etc.. (three) sealing threads: used for sealing connections, mainly for threads, taper threads and taper pipe threads. Two, thread matching level: The thread matching is the loose or tight size between the screwed threads, The level of fit is a combination of deviations and tolerances on the inside and outside threads. (1) for unified inch threads, there are three kinds of thread: 1A, 2A and 3A, and there are three grades of internal thread: The 1B, 2B, and 3B levels are all gap fit. The higher the grade, the tighter the tie. In British threads, deviations are only specified for grades 1A and 2A, deviations from class 3A are zero, and class deviations for 1A and 2A are equal. The larger the grade, the less the tolerance. 1, 1A and 1B class, very loose tolerance level, which is suitable for internal and external thread tolerance match. 2, 2A and 2B class, is the British family of mechanical fasteners, the most common thread tolerance class. 3, 3A and 3B grade, spin forming the most tight fit, suitable for tight fasteners, for security critical design. 4, the external thread, 1A and 2A class has a matching tolerance, 3A class no.. The 1A tolerance is 50% larger than the 2A tolerance, 75% larger than the 3A grade, and the 2B tolerance is 30% greater than the 2A tolerance for internal threads. 1B is 50% larger than 2B, 75% larger than 3B. (two) metric thread, the external thread has three kinds of thread grades: 4h, 6h and 6G, the internal thread has three kinds of thread grades: 5H, 6, H, 7H. (Japan standard thread accuracy grade is divided into I, II and III three, usually under the II class) in metric thread, the basic deviation of H and H is zero. The basic deviation of G is positive, and the basic deviation of E, F and G is negative. As shown: 1 and H are common tolerances for internal threads. They are generally not used as surface coating or with extremely thin phosphating layers. The basic deviation of G position is used for special occasions, such as thicker coating, which is seldom used. 2 and G are often used for 6-9um plating of thin coating, such as product drawings require 6h bolt, its plating thread before using 6G tolerance zone. 3, screw with the best combination of H/g, H/h or G/h, for bolts, nuts and other refined fasteners thread, the standard recommended by the use of 6H/6g coordination (three) thread mark Four 、 the main geometric parameters of self drilling and self drilling thread: (1) big diameter / tooth outer diameter (D1), the diameter of the imaginary cylinder that coincides with the top of the thread. The large diameter of a screw, basically representing the size of the thread Nominal diameter. (two) path / tooth bottom diameter (D2): the imaginary cylinder diameter of the bottom of the screw thread. (three) the distance between teeth (P): the axial distance between adjacent teeth on the middle meridian corresponds to the two points. Inch (25.4 inches) in English The number of teeth in the MM indicates the distance between teeth. The following table lists the tooth distance (Metric) teeth (English) of the commonly used specifications 1, metric self tapping teeth: Specifications S T 1.5 S T 1.9 S T 2.2 S T 2.6 S T 2.9 S T 3.3 S T 3.5 S T 3.9 S T 4.2 S T 4.8 S T 5.5 S T 6.3 S T 8 S T Nine point five The range of teeth was 0.5, 0.6, 0.8, 0.9, 1.1, 1.3, 1.3, 1.3, 1.4, 1.6, 1.8, 1.8,, 2.1, 2.1 2, British self tapping teeth: Specifications 4#, 5#, 6#, 7#, 8#, 10#, 12#, 14# tooth Number AB teeth 2420201918161414 A teeth 2420181615121110 Material Science First, the current market standard parts are mainly carbon steel, stainless steel, copper three kinds of materials. (I) carbon steel. We distinguish between low carbon steel by carbon content in carbon steel, Medium carbon steel and high carbon steel and alloy steel. 1, low carbon steel C% is less than or equal to 0.25% domestic commonly known as A3 steel. Foreign countries are basically called "1008101510181022". Mainly used for 4.8 bolts and 4 nuts, small screws and other products without hardness requirements. (Note: the drill pin is mainly made of 1022 material.) In 2, 0.25%0.45%. At present, the market is basically no use 4, alloy steel: alloy elements in general carbon steel, increase some of the special properties of steel: such as 35, 40 chromium, molybdenum, SCM435, 10B38. Fang screws mainly use SCM435 chrome molybdenum alloy steel, the main components are C, Si, Mn, P, S, Cr, Mo. (two) stainless steel. Performance rating: 45, 50, 60, 70, 80 Mainly divided into austenite (18%Cr and 8%Ni), good heat resistance, good corrosion resistance, good weldability. A1, A2, A4 Martensite and 13%Cr have poor corrosion resistance, high strength and good wear resistance. C1, C2, C4 ferritic stainless steel. 18%Cr has better upsetting and better corrosion resistance than martensite. At present, the market is mainly imported Japanese products. According to the level of the main sub SUS302, SUS304, SUS316. (three) copper. Commonly used material is brass... Zinc copper alloy. The market mainly uses H62, H65 and H68 copper as standard parts. Disk elements used in carbon steel products: Serial number, type, optional material 14.8 stage six angle bolt 1008K 1010 1015K 26.8 stage six angle bolts 103210351040 CH38F 1039 38.8 stage six angle bolt 1035ACR (M10 below) 1040ACR (M12 above) CH38F 1045ACR 1039 10B21 10B33 10B38 48.8 stage six angle bolts CH38F, 1039, 10B21 (M10-M12), 10B33 (M14), 10B38 (M12-M24) 10B21 510.9 stage, six corner bolts, 1045ACR, 10B38 6 / 8 / 1010 level nut 1008K 78 level cap 1015 (M<16) CH38F (M = 16) 810 screw CH38F 1039 10B21 10B33 912 stage nut 1039 10B21 10B33 10B38 10 carriage screws 100810101015 11, six corner stud, CH38F 1039, 10B21, 10B33, 10B38 12 six angle wood screw 1008K 1010 13 self tapping nail, wallboard nail Drill pin, plywood pin 10181022, CH22A 14 machine screws, furniture screws 10081010 Three. The influence of various elements in the material on the properties of steel: 1, carbon (C): to improve the strength of the steel, especially its heat treatment performance, but with the increase of carbon content, plasticity and toughness decreased, and will affect the cold upsetting and weldability of the steel parts. 2, manganese (Mn): to improve the strength of steel parts, and to some extent, improve hardenability. That is, the strength of hardened infiltration is increased during quenching, and manganese can also improve surface quality, but too much manganese is detrimental to ductility and weldability. And it will affect the plating control. 3, nickel (Ni): to improve the strength of steel parts, improve the toughness at low temperature, improve atmospheric corrosion resistance, and can guarantee stable heat treatment effect, reduce the role of hydrogen embrittlement. 4, chromium (Cr): can improve hardenability, Improve wear resistance, improve corrosion resistance, and help maintain strength at high temperature. 5, molybdenum (Mo): can help control hardenability, reduce the sensitivity of steel to temper brittleness, to improve the tensile strength at high temperature has great influence. 6, boron (B): can improve hardenability, and help to make low carbon steel heat treatment to produce the expected response. 7, alum (V): refining austenite grain, improve toughness. 8, silicon (Si): to ensure the strength of steel parts, the appropriate content can improve the plasticity and toughness of steel parts. Four. Brief introduction to the characteristics of stainless steel (304, 316) (1) the three materials are austenitic stainless steel of the 300 series. The chemical composition is as follows: Name C, Si, Mn, P, S, Ni, Cr, Mo, Cu 304M = 0.06 = 1 = 2 = 0.045 = 0.03 8.91-10.0 18.0-20.0 00 316 = 0.03-0.06 = 1 = 2 = 0.045 = 0.03 10.0-14.0 16.0-18.0 2.0-3.0 0 304HC = 0.08 = 1 = 2 = 0.045 = 0.03 8.0-10.5 17.0-19.0 0 1.0-3.0 (two) relationship between main chemical composition and properties of stainless steel. 1, carbon C can increase hardness and strength, the content is too high will reduce its ductility and corrosion resistance 2, chromium Cr can increase corrosion resistance, oxidation resistance, make grain refinement, increase strength, hardness and wear resistance 3, nickel Ni can increase the high temperature strength, corrosion resistance, and reduce the rate of cold work hardening 4, molybdenum Mo increases strength, and has good corrosion resistance to oxides and sea water 5, copper Cu is advantageous to cold processing molding, reduces magnetism (three) other properties of material; 1 、 the material is in normal condition without magnetism. 304M after cold processing, slightly magnetic (about 1.6u-2.0u); 304HC magnetic for (1.01u-1.6u); 316 material after cold processing, magnetic less than 1.01u. 2, all materials have good ductility, easy cold processing molding, tensile strength, yield strength, can meet the requirements. (Ts tensile strength min700N/mm, Ys yield strength min, 450N/mm) (four) conclusion 1, 304M, 304HC, 316, three kinds of materials is currently the 300 series austenitic stainless steel is one of the most widely used materials. Each material obviously difference is: after cold processing, the material magnetism is 316<304HC<304M. 316, the material is resistant to chemical corrosion, corrosion resistance and sea water corrosion resistance, relative to 304M and 304HC to fine. 2, in short, stainless steel standard parts characteristics of corrosion resistance, beautiful appearance and sanitation, but its strength and hardness under normal circumstances is equivalent to the carbon steel (6.8) of the stainless steel products should not be hit, beat, pay attention to the maintenance of the surface roughness, accuracy, and can not use carbon steel products and force are not as readily. Application of force is too large, at the same time because stainless steel has good ductility, easy to produce steel chips stuck on the nut teeth at the level of use, increase the friction force, easy to cause the lock, and the use of carbon steel even if iron filings produced will drop, compared with stainless steel is not easy to lock. Major categories of products (1) six angle bolts (HEXAGON, HEAD, BOLTS); 1, inch bolt reference standard is ANSI/ASME B18.2.1, Japanese standard refers to JIS B1180 (Wei Shiya). British reference BSW916 (Wei Shiya). (1) HEX, MACHINE, BOLT: no division, with tail, half teeth, six angle bolts, (2) HEX, TAP, BOLT: no division, no tail, all teeth, six angle bolts, (3), HEX, CAP, SCREWS: there are Chinese company, with tail, half teeth, six angle bolts, 2. The metric bolt standard is as follows. The difference between them is shown in the table: Old GB, new national standard, ISO standard, DIN (German standard) GB30 GB5780 (half teeth) GB5781 (all teeth) GB5782 (half teeth) GB5783 (all teeth) ISO4016 ISO4018 ISO4014 ISO4017 DIN601 DIN558 DIN931 DIN933 (two) carriage screw / round head square neck bolt (Carriage, Bolts): ANSI/ASME B18.5; DIN603; ISO 8677; GB12; GB14 (three) inner angle bolts (Hexagon, Socket-Head, cap, screws,): DIN912; GB70; ISO4762; ANSI, /ASME, B18.3 (four) six angle wood screws (Hexagon, Head, Lag, Screws): ANSI/ASME B18.2.1 DIN 571 (five) furniture screw (Furniture, screws): according to customer standard (six) and six angle flange bolts (Hexagon, Flange, Bolt): IFI 111, GB 5787, DIN 92 Three, signs, performance grades (1) signs. Six hexagon head bolts and screws (thread diameter larger than 5mm). It should be marked with a convex or concave mark on the top of the head or with a concave sign on the side of the head. Including the performance level, standard. Carbon steel: strength grade marking code consisting of two parts separated by "" "". The "digital" part of the mark code indicates the nominal tensile strength, such as "4" for grade 4.8, and 1/100 for nominal tensile strength 400N/MM2. The meaning of "numbers" and "points after numbers" in a mark code indicates the ratio of yield to strength, that is to say, the nominal yield point or the ratio of nominal yield strength to nominal tensile strength. For example, the yield point of grade 4.8 product is 320 N/mm2. The strength grade mark of stainless steel is composed of two parts separated by "-". The sign of "-" in front of symbol code. Such as: "A2", "A4" and so on mark "-" after the intensity, such as: A2-70 (2) rank. Carbon steel: metric bolts, mechanical grade can be divided into: 3.6, 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9, 12.9, 10 performance levels. Stainless steel is divided into 60,70,80 (austenite), 50,70,80110 (martensite), 45,60 (ferrite) three
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