Quality Assurance
Quality on
every tube.
Every tube we supply is verified before it ships — produced at an API & IATF-certified mill with German ASSEL hot-rolling, full cold-finishing and heat-treatment, 100% non-destructive testing, and a complete metallurgical lab.
01 / Hot Rolling
ASSEL φ180
German Meer ASSEL φ180 hot-rolling technology.
Hot-finished OD 3½–9⅝ in
02 / Cold Work
Draw & Roll
Three cold-drawing lines and φ90 cold-rolling.
±5% wall tolerance
03 / Heat Treatment
Quench & Temper
Dedicated Q&T line for API drilling and high-strength alloy grades.
API drilling & high-strength grades
04 / Precision Finish
Hone & Burnish
Skive and roller-burnishing for ready-to-assemble hydraulic cylinder bores.
ID 2.5–11 in · H7–H9 · Ra 2–8 μin
05 / Inspection
100% NDT
Per customer requirements and product spec: ultrasonic (UT) for internal/external defects, magnetic particle (MPI) for surface, magnetic flux leakage (MFL) for longitudinal/transverse defects, plus dimensional, straightness, and visual inspection.
UT · MPI · MFL · dimensional · straightness · visual · hydrostatic
06 / Metallurgy
Full Lab
Mechanical testing (tensile, yield, elongation, impact), chemical composition verified by heat/lot, hardness on Q&T product, and microstructure examination — grain size per ASTM E112.
Tensile · chemistry · hardness · microstructure
