用什么方法代表什么不銹鋼螺栓的性能等級?

　　在我們的日常生活中常常會遇到一些不銹鋼螺栓的一些情況,像其螺絲頭部都有打上字母或數字的印記,你知道這些字母和數字代表什么嗎?

　　不銹鋼緊固件的表示方法有兩部分組成。第一部分標記鋼的組別;第二部分標記性能等級 例如標記:AB-CD 1. 第一部分由字母和數字組成,字母A表示鋼的類別,數字B表示該類鋼的化學成分(含碳量低于0.03%的不銹鋼,可在數字后面標記L,如A4L-80,常見的表示316L同理) 2. 第二部分標記由兩個數字CD組成,并代表緊固件抗拉強度的1/10

　　不銹鋼螺栓的性能等級8.8指材料的抗拉強度極限800MPa，屈服極限640MPa。

　　不銹鋼螺栓、螺柱、螺柱的性能等級共分10個等級：自3.6至12.9。小數點前面的數字代表材料的拉強度極限的1/100，小數點后面的代表材料的屈服極限與抗拉強度極限之比的10倍。

　　螺母的性能等級分7個等級，從4到12。數字粗略表示不銹鋼螺母保證能承受的最小應力的1/100。

　　對統一英制螺紋，外螺紋有三種螺紋等級：1A、2A和3A級，內螺紋有三種等級：1B、2B和3B級，全部都是間隙配合。等級數字越高，配合越緊。

　　1、1A和1B級，非常松的公差等級，其適用于內外螺紋的允差配合。

　　2、2A和2B級，是英制系列機械不銹鋼緊固件規定最通用的螺紋公差等級。

　　3、3A和3B級，旋合形成最緊的配合，適用于公差緊的不銹鋼標準件，用于安全性的關鍵設計。

　　公制螺紋，外螺紋有三種螺紋等級：4h、6h和6g，內螺紋有三種螺紋等級：5H、6H、7H。螺紋配合最好組合成H/g、H/h或G/h，對于螺栓、不銹鋼螺母等精制緊固件螺紋，標準推薦采用6H/6g的配合.

　　碳鋼：強度等級標記代號由“?”隔開的兩部分數字組成。標記代號中“?”前數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級產品的屈服點為320N/mm2。

　　不銹鋼產品強度等級標志由“—”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

　　碳鋼：公制不銹鋼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。

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　　What method represents the performance level of stainless steel bolts?

　　In our daily life, we often encounter some situations of stainless steel bolts, such as the screw heads are marked with letters or numbers. Do you know what these letters and numbers represent?

　　stainless steel screw

　　The representation method of stainless steel fasteners consists of two parts. The first part marks the steel group; the second part marks the performance level. For example: AB-CD 1. The first part consists of letters and numbers, the letter A indicates the type of steel, and the number B indicates the chemical composition of the steel (carbon For stainless steel less than 0.03%, L can be marked after the number, such as A4L-80, the common meaning is 316L) 2. The second part of the mark is composed of two numbers CD and represents 1/100 10

　　Stainless steel screw performance level

　　Stainless steel bolt performance level 8.8 refers to the material's tensile strength limit 800MPa, yield limit 640MPa.

　　Stainless steel bolts, studs, stud performance levels are divided into 10 levels: from 3.6 to 12.9. The number before the decimal point represents 1/100 of the material's tensile strength limit, and the number after the decimal point represents 10 times the ratio of the material's yield limit to the tensile strength limit.

　　Nut performance grades are divided into 7 grades, from 4 to 12. The number roughly indicates 1/100 of the minimum stress that the stainless steel nut is guaranteed to withstand.

　　For unified inch threads, there are three thread grades for external threads: 1A, 2A and 3A, and three grades for internal threads: 1B, 2B and 3B, all of which are clearance fit. The higher the level number, the tighter the fit.

　　Class 1, 1A and 1B, very loose tolerance class, which is suitable for tolerance matching of internal and external threads.

　　Grades 2, 2A and 2B are the most common thread tolerance grades specified for mechanical stainless steel fasteners in the British series.

　　Grades 3, 3A and 3B, screwed together to form the tightest fit, suitable for tight tolerance stainless steel standard parts, used for critical design of safety.

　　Metric thread, external thread has three thread grades: 4h, 6h and 6g, internal thread has three thread grades: 5H, 6H, 7H. The thread fit is best combined into H / g, H / h or G / h. For bolts, stainless steel nuts and other refined fastener threads, the standard recommends 6H / 6g fit.

　　Carbon steel: The code of strength grade mark is composed of two parts separated by “?”. The meaning of the number part before the "?" In the mark code indicates the nominal tensile strength. For example, "4" in grade 4.8 indicates 1/100 of the nominal tensile strength 400N / MM2. The “?” In the mark code and the number part after the point indicate the yield strength ratio, that is, the ratio of the nominal yield point or the nominal yield strength to the nominal tensile strength. For example, the yield point of grade 4.8 products is 320N / mm2.

　　Stainless steel product strength grade mark consists of two parts separated by "-". The symbol before the "-" in the sign code indicates the material. Such as: A2, A4 and other signs "-" after the intensity, such as: A2-70

　　Carbon steel: Metric stainless steel bolts can be divided into mechanical performance levels: 3.6, 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9, 12.9 a total of 10 performance levels.