J524B vs J525B hydraulic tubing

[Lathiew]

Does anyone know when and where to use J524B or J525B hydraulic line ?

I know that J524B is seamless tubing and J525B is welded tubing but they seem to have same yield and burst pressure....

Why should I use seamless tubing since it is more expensive than welded....

Thank you !

 

[kcj]

Are your connections bite type or flared?

We have had two issues with flare quality with certain welded tubes:
-weld flash on the inside of tube causes a defect in flare surface.
-hardness of tube at the weld causes defect in flare surface.

Our applications are routine hydraulic systems with oil or water glycol at pressures to 5000 psi, not process or instrumentation.

Both problems have been rampant with offshore china sourced tubing. It is becoming very hard to control the source from the vendors.

37 degree flare and ORFS both have similar issues

Problems are worse with stainless tubing than with carbon steel. Material hardness, ductility, and springback are factors.

Hydraulic cone & push type of 37 degree flare machine has the most problems.

The Parker ParFlange rolled/impacted method of flaring provides much better flare quality, but still has some issues with tubing ID quality.

Tubing specs apply more to material and OD dimensions and finish, and ID specs are rather vague and loose.

We are looking for a better specification for tubing. Any input appreciated.

kcj