關于擰螺栓這件事，用什么方法擰?擰緊需要遵守怎么的流程?不是裝配工人自己定的，而是設計師定義好的，用什么工具?怎么操作?都是有標準規(guī)范的。
How to screw the bolt? What process should be followed for tightening? It is not determined by the assembler himself, but defined by the designer. What tools are used? How? There are standards and specifications.
擰螺栓這么簡單的事情，怎么還定一個操作規(guī)范呢?其實擰螺栓沒有想象的那么簡單，擰螺栓是為了使螺栓獲得一個初始的預緊力，這個預緊是起什么作用的呢?
How can an operation specification be set for such a simple thing as tightening bolts? In fact, screwing the bolt is not as simple as expected. Screwing the bolt is to obtain an initial preload. What role does this preload play?
1、傳遞橫向力或扭矩
1. Transfer lateral force or torque
螺栓預緊力使被連接件接觸面之間產生壓力，接觸面之間壓力越大，可傳遞橫向力就越大。當接觸面壓力足夠大時，橫向力就全部由摩擦力傳遞了，螺栓僅承受預緊力，不再受剪應力和壓應力了，螺栓的性就增加了很多。
The bolt preload generates pressure between the contact surfaces of the connected parts. The greater the pressure between the contact surfaces, the greater the transverse force that can be transmitted. When the pressure on the contact surface is large enough, the transverse force is transmitted by friction. The bolt only bears the preload and is no longer subject to shear stress and compressive stress, and the safety of the bolt is increased a lot.

2、密封作用
2. Sealing action
當螺栓連接用于壓力管道或壓力容器時，螺栓需要有足夠的預緊力，起到密封作用，總的螺栓預緊力不能小于接觸面間流體的壓力。
When the bolt connection is used for pressure pipes or pressure vessels, the bolt shall have sufficient preload to seal. The total bolt preload shall not be less than the fluid pressure between the contact surfaces.
3、防止結構開裂
3. Prevent structural cracking
一般受疲勞載荷的螺栓連接是不允許被連接件開縫的，一旦被連接件之間產生縫隙，螺栓拉力就會隨著外拉力載荷的增加而快速增加，下圖為螺栓拉力與外載荷的曲線圖，我們可以看到，在曲線的前半部分，被連接件之間還沒有開縫，螺栓拉力增長緩慢，被連接件開縫之后，螺栓拉力快速增加。
Generally, the bolted connections subject to fatigue load are not allowed to be jointed. Once there is a gap between the connected parts, the bolt tension will increase rapidly with the increase of external tension load. The following figure is the curve of bolt tension and external load. We can see that there is no slit between the connected parts in the first half of the curve, and the bolt tension increases slowly, After being slotted by the connector, the bolt tension increases rapidly.
螺栓的分類
Classification of bolts
螺栓按照性能等級分為3.6、4.8、5.6、6.8、8.8、9.8、10.9、12.9八個等級，其中8.8級以上(含8.8級)螺栓材質為低碳合金鋼或中碳鋼并經熱處理(淬火+回火)，通稱高強度螺栓，8.8級以下(不含8.8級)通稱普通螺栓。
Bolts are divided into 8 grades according to performance grades: 3.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9 and 12.9. Bolts above grade 8.8 (including grade 8.8) are made of low-carbon alloy steel or medium carbon steel and heat treated (quenching + tempering), which are generally referred to as high-strength bolts, and bolts below grade 8.8 (excluding grade 8.8) are generally referred to as ordinary bolts.
螺栓按照性能等級分為3.6、4.8、5.6、6.8、8.8、9.8、10.9、12.9八個等級，其中8.8級以上(含8.8級)螺栓材質為低碳合金鋼或中碳鋼并經熱處理(淬火+回火)，通稱高強度螺栓，8.8級以下(不含8.8級)通稱普通螺栓。
Bolts are divided into 8 grades according to performance grades: 3.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9 and 12.9. Bolts above grade 8.8 (including grade 8.8) are made of low-carbon alloy steel or medium carbon steel and heat treated (quenching + tempering), which are generally referred to as high-strength bolts, and bolts below grade 8.8 (excluding grade 8.8) are generally referred to as ordinary bolts.
用于緊固高強度扭剪螺栓，并且在緊固完成后將剪斷的梅花頭保留在套筒內部不掉落，隨后扣動扳機將梅花頭彈出，動力為220V或110V交流電源，相比較與傳統(tǒng)六角螺栓，扭剪螺栓配合電動電動扭剪扳手，施工方便快捷，扭矩控制準確并且方便檢查。
It is used to fasten the high-strength torsion shear bolt, and keep the cut plum blossom head inside the sleeve after fastening, and then pull the trigger to pop up the plum blossom head. The power is 220V or 110V AC power supply. Compared with the traditional hexagonal bolt, the torsion shear bolt is matched with the electric torsion shear wrench, which is convenient and fast in construction, accurate in torque control and convenient for inspection.
電動扭矩扳手專用于緊固有扭力要求的六角螺栓，動力為220v或110v交流電源，帶有扭矩控制器，在一定范圍內輸出扭矩可調。且控制精度高，重復精度高可達±3%，摒棄電機反正轉，采用更加機械式反正轉，減少電機損耗，提高可靠性。
Electric torque wrench is specially used to fasten hexagon bolts with torque requirements. The power is 220V or 110V AC power supply, with torque controller, and the output torque is adjustable within a certain range. The control precision is high, and the repetition precision can reach ± 3%. Instead of the motor reverse rotation, the more advanced mechanical reverse rotation is adopted to reduce the motor loss and improve the reliability.