GB/T9808 STM-R780 High Straightness Seamless Cold Drawn Steel Tube For Drilling
GB/T9808 STM-R780 High Straightness Seamless Steel Tubes for Drilling
our products apply to geological core drilling,water well drilling,hydrogeoligical drill,casing material for engineering drilling,core tube material and casing coupling Seamless Steel Tubes,ordinary drill pipe material and drill pipe joint Seamless Steel Tubes,rope coring drill pipe material and drill pipe joint Seammless Steel Tubes,drill collar material and drill collar lock joint Seamless Steel Tubes.
Size:
OD:33-340mm WT:2-28mm L:4000mm-12500mm
Steel Grade:
ZT380,ZT490,ZT520,ZT540,ZT590,ZT640,ZT740
The Production method:
Hot rolling(extrusion) or cold drawing(rolling) seamless method.
Delivery State:
Hot rolling(extrusion)steel tubes should be delivered with hot rolling condition or hot finished.Cold drawn(rolling) steel tubes should be delivered with hot finished.
Surface quality
There is no visual visible cracks,rolling, folding,scarring and abscission layer in the internal and external surfaces of the steel pipe.
Test:
Tensile tast
Ultrasonic inspection
Eddy current inspection
Magnetic flux leakage inspection
Tolerance of Outer Diameter and Wall Thickness
| Standard | Production Method | Tube Size | Tolerance | |
| GB/T 9808-2008 | Hot rolled | OD | (+1.0%D) or +0.65 (-0.5%D) -0.35 | |
| WT | ≤10 | (+15%S)or +0.45 (-10%S) -0.35 | ||
| >10 | (+12.5%S, -10%S) | |||
| Cold Drawn(rolled) | OD | ±0.50%D or ±0.20 | ||
| WT | ±8%S or ±0.15 | |||
| Q(N)/ T118-2010 | Cold Drawn | OD | OD | ±0.40%D or ±0.20 |
| WT | WT | ±7%S or ±0.15 | ||
Mechanical Property
| No. | Grade | Tensile Strangth Rm/MPa | Specifies the non-proportional extension strength Rp0.2/MPa | Percentage elongation after fracture A/% |
| No less than | ||||
| 1 | ZT380 | 640 | 380 | 14 |
| 2 | ZT490 | 690 | 490 | 12 |
| 3 | ZT520 | 780 | 520a | 15b |
| 4 | ZT540 | 740 | 540 | 12 |
| 5 | ZT590 | 770 | 590 | 12 |
| 6 | ZT640 | 790 | 640 | 12 |
| 7 | ZT740 | 840 | 740 | 10 |
| a Grade ZT520 measure RP0.5 bGrade ZT520 use tensile sample S4 S5 or S6 in GB/T 228 | ||||
Application:
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