High Precision Seamless Steel Pipe NBK 8mm Wall Thickness
High Precision Seamless Steel Pipe NBK 8mm Wall Thickness
OD:4-76mm
Wall thickness:0.5-8mm
Material:E215 E235 E355 ST35,ST37.4,ST45,ST52.4 etc
Chemical Composition
| Steel grade | C max. | Si max. | Mn max. | P max. | S max. | Altot min. | |
| Name | Number | ||||||
| E215 | 1.0212 | 0.10 | 0.05 | 0.7 | 0.025 | 0.015 | 0.025 |
| E235 | 1.0308 | 0.17 | 0.35 | 1.2 | 0.025 | 0.015 | -- |
| E355 | 1.0580 | 0.22 | 0.55 | 1.6 | 0.025 | 0.015 | -- |
Tolerance
| Outer Diameter | Allowable tolerance | special tolerance | ||
| GB/T3639 | DIN2391 | OD | WT | |
| 4mm-20mm | ±0.10mm | ±0.08mm | ±0.05mm | ±0.05mm |
| 20mm-30mm | ±0.10mm | ±0.08mm | ±0.08mm | ±0.08mm |
| 31mm-40mm | ±0.15mm | ±0.15mm | ±0.10mm | ±0.08mm |
| 41mm-60mm | ±0.20mm | ±0.20mm | ±0.15mm | ±0.15mm |
| 61mm-80mm | ±0.30mm | ±0.30mm | ±0.20mm | ±0.20mm |
| 81mm-120mm | ±0.45mm | ±0.45mm | ±0.30mm | ±0.30mm |
Delivery condition:
The tubes can be produced in the following delivery conditions:
BK (+C) Cold finished/hard (cold finished as drawn).
No heat treatment after the last cold forming process.
BKW (+LC) Cold finished/soft (lightly cold worked)
After the last heat treatment there is a light finishing pass (cold drawing).
BKS (+SR) Cold finished/stress relieve annealed.
After the final cold forming process the tubes are stress relieve annealed.
GBK (+A) Annealed.
After the final cold forming process the tubes are annealed in a controlled atmosphere.
NBK (+N) Normalized. (Mainly focus on)
After the final cold forming process the tubes are annealed above the upper transformation point in a controlled atmosphere
Production routing:
Quality carbon steel from bao steel etc big mill, cold drawing the heat treatment without oxidization , NBK condition. Do nondestructive testing ,HT tests and do dipping oil antirust protection, Packed tube in wooden boxes.
Main feature:
High precision
Excellent brightness
No oxidization on outer and inner walls after heat treatment
High cleanness of inside wall
High pressure
No deformation after clod bending
No crack after flaring and flattening
Color : Gray with white
Application:
Hydraulic system
Automobile
Tolerance
Name | Scope mm | DIN seriesmm |
| OD | 04-30 | ±0.08 |
| OD | 31-40 | ±0.15 |
| OD | 41-50 | ±0.20 |
| OD | 51-60 | ±0.25 |
| Wall | 0.5-7 | ±10% |
Key words
Precision Steel Tubes
Precision Seamless Steel Tubes
High Precision Seamless Steel Tubes/Pipe
Get in Touch
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