4.2.2 Piston rod chromating and surface hardness .
Eternal company ensure that every piece piston rod would be surface hardened before chromating ,
surface hardness is HRC55~60 , Chromating film thickness is 0.03~0.04mm if there is no other specific
4.3 Seal ring and O ring
According to the customers’ requirements and working condition , eternal company would choose suitable
seal ring kit , seal ring brand include :Parker , Merkel , NOK , Guangzhou Rubber institute , Taiwan brand etc . Eternal company would supply suitable seal solution for their customer so that hydraulic cylinder has more
lifetime , easy maintenance and simple repairing .
4.4 Tube and flange welding
The welding on cylinder tube and flange would be Ultrasonic tested every time , the welding seam would be
cleaned before machining .Eternal company ensure that every welding seam has no any leak during lifetime
4.5 Assembly and pressure test
Before hydraulic cylinder is assemblied , every spare parts would be measured and cleaned .After hydraulic
cylinder is assemblied , pressure test would be carried out one By one , eternal company ensure that testing
pressure is higher 30%-50% than working pressure , and pressure holding time 30~60 minutes is necessary . Every piece hydraulic cylinder must be tested completely without any leak .
4.6 Painting and storage .
After hydraulic cylinder pass through pressure test , painting is necessary .