Honing Technology in Honed Tubes: A Closer Look

Honing is a traditional technology and method used in ID treatment of metal parts, especially for steel tubes. 

Honing is done through rotation of honing stones inside the parts, and the internal surface of parts will be as smooth as polished surface. While honing is more than polishing, because it removes excessive material/allowance to ensure the tight tolerance of ID. 

One typical usage of honing is hydraulic cylinder barrel. The hydraulic cylinder barrel must have very tight ID tolerance like H8 or H9 and perfect roughness like Ra0.4um max, because a piston rod with seals will move back and forth inside the barrel. 

Honed tubes are always honed by honing stones first to ensure the ID tolerance like H8 or H9, and then polished to ensure the roughness of internal surface like Ra0.4um max.