Hydraulic Cylinder Tubes from China: Honed and SRB

A mill-type hydraulic cylinder. Its barrel is a finished cylinder tube like the ones described here. Photo: Rstom03, CC BY-SA 3.0, via Wikimedia Commons.

Honed and skived and roller burnished hydraulic cylinder tubes from China: base tubes, bore tolerance, surface finish and what to check before shipment.

Hydraulic cylinder tubes are steel tubes whose inside surface is finished so a piston and its seals can run in them: smooth, round, straight and held to a close inside diameter tolerance. Two ways of finishing the bore are common:

Typical specification

• Base tube: cold drawn seamless tube, for example EN 10305-1 E355 +SR (ST52 BKS under the old DIN name).
• Inside diameter tolerance: commonly H8 or H9.
• Bore roughness: commonly Ra 0.4 µm or better.
• Straightness, wall thickness and length as your cylinder design requires.

What to check before shipment

• Measure the bore at several points along each tube, not only at the ends.
• Check bore roughness with a surface roughness tester, and look inside for scratches and chatter marks.
• Confirm that the base tube certificate (grade and heat number) matches the tubes.
• The bore must be oiled and both ends capped, so it does not rust at sea.

How to order through SinoAli

Send us the inside diameter, wall thickness, length, tolerance, finish and quantity. Ask us which mill the material comes from and which certificate it carries. When your contract is with SinoAli, you pay the deposit only to the company account named in your contract, you choose the inspection company, and you pay the balance after you have seen the inspection report. Buying from a new supplier for the first time? Read How to buy steel from China without getting scammed.

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Send your cylinder tube specification