How to correctly prepay stainless steel bolts and nuts to thread galling
Publish Time: 2019-03-01 Origin: Site
Because stainless steel 304 have good ductility, if you use it misemploy, it will be thread galling, and if you still use electric wrench after thread galling, the bolt will be broken.
there are below advice way to avoid the thread galling,
1. chose right bolts,
a, chose suitable bolt length and diameter, the bolt is better to come out nut 1-3 thread after finish assembly.
b. to make sure the mechanical capacity full fit the requirement.
2. reduces the friction coefficient,
a, make it clear of the thread surface,
b, coating wax or lubricating oil ( such as Grease, 40# engine oil)
3. correct way to use
a, nut should be vertical with the bolt , no incline.
b, when you assembly, please make the force is stable, the torque should not more than safe torque,( please see below safe torque list)
c , please try your best to use torque wrench or socket spanner, do not use electric wrench or monkey wrench.
d. do not use in high temperature, please do not rotation too fast, to avoid thread galling becasue of temperature go up very fast. ( such as electric wrench)
4. safe torque list ( unit N.m, for your reference)
| size | M4*0.7 | M5*0.8 | M6*1.0 | M8*1.25 | M10*1.5 | M12*1.75 | M14*2.0 | M16*2.0 | M18*2.5 | M20*2.5 | M22*2.5 | M24*3.0 |
| safe torque | 2.5 | 5 | 9 | 20 | 40 | 55 | 100 | 150 | 180 | 220 | 400 | 510 |
5.We advance using Goshen shen wax prepay lock nuts to thread galling