1、 Bolt overview

螺栓，機械零件，配用螺母的圓柱形帶螺紋的緊固件。螺栓：由頭部和螺桿（帶有外螺紋的圓柱體）兩部分組成的一類緊固件，需與螺母配合，用于緊固連接兩個帶有通孔的零件。這種連接形式稱螺栓連接。如把螺母從螺栓上旋下，又可以使這兩個零件分開，故螺栓連接是屬于可拆卸連接。

Bolts, mechanical parts, cylindrical threaded fasteners with nuts. Bolt: a kind of fastener composed of head and screw (cylinder with external thread), which needs to be matched with nut to fasten and connect two parts with through holes. This type of connection is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection belongs to removable connection.

按連接的受力方式分：分普通的和有鉸制孔用的。按頭部形狀分：有T形的，六角頭的，圓頭的，方形頭的，沉頭的等等。其中六角頭是常用的。一般沉頭用在要求連接的地方。應(yīng)用非常廣泛。

According to the stress mode of connection, it is divided into ordinary and reamed holes. According to the head shape: T-shaped, hexagonal, round, square, countersunk, etc. Hexagon head is commonly used. Generally, countersunk head is used where connection is required. It is widely used.

螺栓有很多叫法，每個人的叫法可能都不同，有人叫成螺釘，有人叫成螺栓釘，有人叫成標準件，有人叫成緊固件。雖然有這么多叫法，但意思都是一樣的，都是螺栓。螺栓是緊固件的通用說法。螺栓的原理是利用物體的斜面圓形旋轉(zhuǎn)和摩擦力的物理學和數(shù)學原理，循序漸進地緊固器物機件的工具。

There are many names for bolts, and everyone may have different names. Some are called screws, some are called bolt nails, some are called standard parts, and some are called fasteners. Although there are so many names, they all mean the same. They are all bolts. Bolt is a common term for fasteners. The principle of bolt is a tool for fastening utensils and mechanical parts step by step by using the physical and mathematical principles of inclined circular rotation and friction of objects.

螺栓在日常生活當中和工業(yè)生產(chǎn)制造當中，是少不了的，螺栓也被稱為工業(yè)之米?？梢娐菟ǖ倪\用之廣泛。螺栓的運用范圍有：電子產(chǎn)品，機械產(chǎn)品，數(shù)碼產(chǎn)品，電力設(shè)備，機電機械產(chǎn)品。船舶，車輛，水利工程，甚化學實驗上也有用到螺栓。反正是超多地方都有用到螺栓的。特如數(shù)碼產(chǎn)品上面用到的精密螺栓。DVD，照相機、眼鏡、鐘表、電子等使用的微型螺栓;電視、電氣制品、樂器、家具等之一般螺栓;于工程、建筑、橋梁則使用大型螺栓、螺帽;交通器具、飛機、電車、汽車等則為大小螺栓并用。螺栓在工業(yè)上負有重要任務(wù)，只要地球上存在著工業(yè)，則螺栓之功能永遠重要。

Bolts are indispensable in daily life and industrial production and manufacturing. Bolts are also known as the rice of industry. It can be seen that bolts are widely used. The application scope of bolts includes: electronic products, mechanical products, digital products, power equipment, electromechanical mechanical products. Bolts are also used in ships, vehicles, hydraulic engineering, and even chemical experiments. Anyway, bolts are used in many places. Such as precision bolts used in digital products. Micro bolts for DVD, camera, glasses, clocks, electronics, etc; General bolts for TV, electrical products, musical instruments, furniture, etc; As for engineering, construction and bridges, large bolts and nuts are used; Transportation equipment, aircraft, trams, automobiles, etc. are both large and small bolts. Bolts have important tasks in industry. As long as there is industry on the earth, the function of bolts will always be important.

二、螺栓標志、性能等級

2、 Bolt mark and performance grade

（1）、標志。六角頭螺栓和螺釘（螺紋直徑≥5mm）。需在頭部頂面用凸字或凹字標志，或在頭部側(cè)面用凹字標志。包括性能等級、廠標。碳鋼：強度等級標記代號由“·”隔開的兩部分數(shù)字組成。標記代號中“·”前數(shù)字部分的含義表示公稱抗拉強度，如4.8級的“4”表示公稱抗拉強度400N/MM2的1/100。標記代號中“·”和點后數(shù)字部分的含義表示屈強比，即公稱屈服點或公稱屈服強度與公稱抗拉強度之比。如4.8級產(chǎn)品的屈服點為320N/mm2。不銹鋼產(chǎn)品強度等級標志由“—”隔開的兩部分組成。標志代號中“—”前符號表示材料。如：A2，A4等標志“—”后表示強度，如：A2-70

(1) . signs. Hexagon head bolts and screws (thread diameter ≥ 5mm). It is necessary to mark the head with convex or concave characters on the top surface or concave characters on the side of the head. Including performance grade and factory standard. Carbon steel: the strength grade marking code consists of two parts separated by "·". The meaning of the number before "·" in the marking code indicates the nominal tensile strength. For example, "4" in grade 4.8 indicates 1 / 100 of the nominal tensile strength of 400N / mm2. The meaning of "·" and the number after the point in the marking code indicates the yield ratio, that is, the nominal yield point or the ratio of nominal yield strength to nominal tensile strength. For example, the yield point of grade 4.8 products is 320n / mm2. The strength grade mark of stainless steel products consists of two parts separated by "-". The symbol before "-" in the sign code indicates the material. For example, A2, A4 and other signs indicate strength after "-", such as A2-70

（2）、等級。碳鋼：公制螺栓機械性能等級可分為：3.6、4.6、4.8、5.6、5.8、6.8、8.8、9.8、10.9、12.9共10個性能等級。不銹鋼分為60,70,80(奧氏體)；50,70,80,110(馬氏體)；45,60（鐵氏體）三類。

(2) , grade. Carbon steel: the mechanical property grade of metric bolt can be divided into 10 performance grades: 3.6, 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9 and 12.9. Stainless steel is divided into 60, 70 and 80 (austenite); 50,70,80110 (martensite); 45,60 (ferrite) three types.

三、目前市場螺栓標準件主要有碳鋼、不銹鋼、銅三種材料。

3、 At present, the bolt standard parts in the market mainly include carbon steel, stainless steel and copper.

（一）碳鋼。我們以碳鋼料中碳的含量區(qū)分低碳鋼，中碳鋼和高碳鋼以及合金鋼。

（1） Carbon steel. We distinguish low carbon steel, medium carbon steel, high carbon steel and alloy steel by the content of carbon in carbon steel.

1、低碳鋼C%≤0.25%國內(nèi)通常稱為A3鋼。國外基本稱為1008，1015，1018，1022等。主要用于4.8級螺栓及4級螺母、小螺栓等無硬度要求的產(chǎn)品。（注：鉆尾釘主要用1022材料。）

1. Low carbon steel C% ≤ 0.25% is commonly referred to as A3 steel in China. It is basically called 1008101510181022 abroad. It is mainly used for grade 4.8 bolts, grade 4 nuts, small bolts and other products without hardness requirements（ Note: the drill tail nail is mainly made of 1022 material.)

2、中碳鋼0.25%

2. Medium carbon steel 0.25% < C% ≤ 0.45%   It is generally called No. 35 and No. 45 steel in China and 1035, ch38f, 1039, 40ACr, etc. in foreign countries. It is mainly used for Grade 8 nuts, grade 8.8 bolts and grade 8.8 hexagon socket products.

3、高碳鋼C%>0.45%。目前市場上基本沒使用

3. High carbon steel C% > 0.45%. It is basically not used in the market at present

4、合金鋼：在普碳鋼中加入合金元素，增加鋼材的一些特殊性能：如35、40鉻鉬、SCM435，10B38。芳生螺絲主要使用SCM435鉻鉬合金鋼，主要成分有C、Si、Mn、P、S、Cr、Mo。

4. Alloy steel: alloy elements are added to ordinary carbon steel to increase some special properties of steel, such as 35, 40 chromium molybdenum, SCM435, 10b38. The aromatic screw mainly uses SCM435 chromium molybdenum alloy steel, and the main components are C, Si, Mn, P, s, Cr and mo.

（二）不銹鋼。

（2） Stainless steel.

主要分奧氏體（18%Cr、8%Ni）耐熱性好，耐腐蝕性好，可焊性好。A1，A2，A4

It is mainly divided into austenite (18% Cr, 8% Ni) with good heat resistance, corrosion resistance and weldability. A1，A2，A4

馬氏體、13%Cr耐腐蝕性較差，強度高，耐磨性好。C1，C2，C4鐵素體不銹鋼。18%Cr鐓鍛性較好，耐腐蝕性強于馬氏體。目前市場上進口材料主要是日本產(chǎn)品。按級別主要分SUS302、SUS304、SUS316。

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 property and stronger corrosion resistance than martensite. At present, the imported materials on the market are mainly Japanese products. It is mainly divided into SUS302, SUS304 and SUS316 by level.

（三）銅。常用材料為黃銅…鋅銅合金。市場上主要用H62、H65、H68銅做標準件。

（3） Copper. Common materials are brass... Zinc copper alloy. H62, H65 and H68 copper are mainly used as standard parts in the market.

螺栓按照材料分：碳鋼的級別與不銹鋼的級別不一樣。

Bolts are divided according to material: the grade of carbon steel is different from that of stainless steel.

碳鋼常用的有：3.6級，4.6級，4.8級，5.6級5.8級6.8級8.8級9.8級10.9級12.9級，可以查GB/T3098.1-2000版。

Commonly used carbon steels are: grade 3.6, grade 4.6, grade 4.8, grade 5.6, grade 5.8, grade 6.8, grade 8.8, grade 9.8, grade 10.9 and grade 12.9. You can refer to GB / t3098.1-2000.

每種級別都有自己的規(guī)定，包括材料牌號，產(chǎn)品硬度，抗拉強度，屈服強度，破壞扭力等。

Each grade has its own regulations, including material grade, product hardness, tensile strength, yield strength, failure torque, etc.

比如以9.8級螺栓為例：9指材料的公稱抗拉強度為900N/mm2，8指屈服強度與抗拉強度的比值0.8（取小數(shù)點后的一位8），這兩個數(shù)中間加點就表示9.8。其硬度HV290-360.

For example, take grade 9.8 bolt as an example: 9 refers to the nominal tensile strength of the material is 900N / mm2, and 8 refers to the ratio of yield strength to tensile strength of 0.8 (take the eighth place after the decimal point). The addition of a point between these two numbers means 9.8. Its hardness is hv290-360

四、各種螺栓技術(shù)參數(shù)

4、 Technical parameters of various bolts

依相關(guān)標準，螺栓性能等級分3.6、4.6、4.8、5.6、6.8、8.8、9.8、10.9、12.9等10余個等級，其中8.8級及以上螺栓材質(zhì)為低碳合金鋼或中碳鋼并經(jīng)熱處理（淬火、回火），通稱為高強度螺栓，其余通稱為普通螺栓。螺栓性能等級標號有兩部分數(shù)字組成，分別表示螺栓材料的公稱抗拉強度值和

According to relevant standards, the performance grades of bolts are divided into more than 10 grades, such as 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9 and 12.9. Among them, bolts of grade 8.8 and above are made of low-carbon alloy steel or medium carbon steel and are generally called high-strength bolts after heat treatment (quenching and tempering), and the rest are generally called ordinary bolts. The bolt performance grade is composed of two numbers, which respectively represent the nominal tensile strength value and