| BK |
BKW |
BKS |
GBK |
NBK |
Q+T |
| +C |
+LC |
+SR |
+A |
+N |
| Cold rolled |
Cold drawn |
Stress relieved |
Annealed |
Normalized |
Quenched+Tempered |
7. Bore treatment: Honing, skiving&roller burnishing
8. Bore roughness control: Ra0.25um max or Ra0, 35um max for honed tubes, Ra0.25um max for skived&roller burnished tubes.
9. End finish: Plain ends with square cuts, free of burrs for honed tubes. Little bevelled ends for skived&roller burnished tubes.
10. Standard export packing: In bundles tied with steel strips. Int&ext oil coating. End plastic caps. External packing by PVC bags and knit bags.
11. Customized packing and marking can be provided upon request.
12. H8 tolerance:
| ID range |
Tolerance |
ID range |
Tolerance |
| 18< d ≤30 |
+0/+0.033 |
180< d ≤250 |
+0/+0.072 |
| 30< d ≤50 |
+0/+0.039 |
250< d ≤300 |
+0/+0.081 |
| 50< d ≤80 |
+0/+0.046 |
300< d ≤315 |
+0/+0.081 |
| 80< d ≤120 |
+0/+0.054 |
315< d ≤400 |
+0/+0.089 |
| 120< d ≤180 |
+0/+0.063 |
400< d ≤500 |
+0/+0.097 |
13. Difference between honed tube and skived&roller burnished tube: In hydraulic cylinder industry, there are 2 solutions for bore treatment: Honing, and skiving&roller burnishing. Honing or skiving&roller burnishing leads to different internal surface image, but both ensure good roughness.
14.FREQUENTLY ASKED QUESTIONS
1.) MOQ: Generally Min Order Quantity can be 2-3 tons/size for tubes with OD below 250mm, and 10 tons/size for tubes with OD above 250mm. Sometimes, it depends on steel grade you need. If you need special grade like E410, E470 or alloy steel tube, MOQ should be 10 tons/size at least.
2.) Delivery Time: Generally, our delivery time for honed tubes is around 40-60 days depending on the sizes and quantities. It will take us 15-30 days to get raw material. For example, if you need 3 tons of small size honed tubes 50mm*40mm with roughness of Ra0.25um max, it will take us at least 30 days to hone this size.
3.) Warranty&Guarantee: Warranty&guarantee period is 6 months since we deliver the tubes, and we are not responsible for quality problem caused by wrong unloading or storage after shipment. We welcome customer’s inspection before shipment.
4.) Quality Control: 90% of the tubes are made from hot rolled seamless pipes. So, quality of raw material determined quality of finished tubes. We purchase raw material from stable suppliers who are leading steel mills, and we inspect the raw material as per the specifications. During our production procedure, there is inspection and quality control in every stage.
