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Chuanghe Fastener Co., Ltd.

  • Address:No. 2 buildings, Lizhou industrial Park,Shangshanqi, Zhushan District, Dongcheng Town, Dongguan City, China.
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Company News
Company News

How to tighten threaded fasteners with three main ways you use

Views: 26Date: 2013-09-12Typeface: Big Small
I believe people in the industry understand that we are in the fastener , choose the method of tightening threaded connections , tighten its also understand various ways according to the design characteristics of the degree of dispersion of the initial preload to carry out the requirements preload size , conditions of use , etc. , a reasonable choice tightening method . Fastening screw tightening factor is to choose the method is an important condition . Threaded fasteners tightened its laws are torque method , the slope of the torque angle method and the method of three commonly used methods typically tighten .

1 , corner method

Angle method that when the bolts are tightened relative rotation of the nut at an angle , called the fastening angle , a fastening to a certain angle as an index to the initial preload force control method. The method can tighten the elastic and plastic zones use . According fastening corners and shows the relationship between preload , QF dramatic changes in the slope of the curve , with the tightening angle setting error , preload dispersion becomes larger . Thus , the self -tapping screw is a rigid connecting member and the bolt of the occasion , the elastic fastening region is detrimental ; fastening the plastic zone , the initial dispersion of the preload depends on the yield point of the bolt , while the angular error has little influence , so that the fastening method can maximize the advantages of strength bolts ( you can get a higher preload ) .

It should be noted that the method of tightening tightening the plastic zone causes the bolt shank portion and the threaded shaft portion is plastically deformed , therefore, the poor ductility of the bolt and the screw should be considered the case of repeated use of its applicability. In addition, preload is too large , it will cause damage to the connected parts of the case , it must yield point of the bolt and the upper limit for the tensile strength requirements .

2 , the torque slope method

QF torque curve slope method is the slope of the torque value changes as an index of the initial preload force control method. This method is usually to tighten the bolts fastening axial force yield as a control target value of the initial preload . The bolt tightening method is generally an initial preload in the dispersion is small and the requirements to maximize the strength of the bolt circumstances. However, since the method of the initial preload clamping force control and the corner of the plastic zone basically the same , so the yield point of the bolt to be strictly controlled. The method and the plastic zone tightening Compared corner , bolts and other aspects of plastic that is used repeatedly fewer problems arise , there are certain advantages, but , fastening tools more complicated , but also more expensive.

3, the torque method

Torque and torque method is the use of the linear relationship between preload and fastened in the elastic zone control method. This method is tightened, only a certain tightening torque control , therefore , because the method is simple, is a general tightening conventional methods . However, because about 90% of the tightening torque acting on the thread friction and the friction bearing surfaces consumption , real role in the axial preload force had only about 10%, the dispersion of the initial preload , with the friction during tightening changing the degree of control factors , and thus the degree of tightening the larger discrete method suitable for one fastening part , is not suitable for important and critical parts of the connection .