TORICH INTERNATIONAL LIMITED
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GB/T 14291 Welded Q235A/Q235B Steel Tubes for Mine Liquid Service
Application:Mine wind, drainage, drainage gas pressure and the pulp conveying with straight seam welded steel pipe
Size:L--4~12m
OD--21.3-660mm
WT--2.5-14mm
Grade:Q235A,Q235B,Q295A,Q295B,Q345A,Q345B
Manufacture method:High-frequency resistance welding
Delivery state:Steel pipe should be straight seam tube flat end light delivery.The supply and demand both sides talks things over, can also according to the weld heat treatment delivery status or other status.
TABLE 1 Allowable deviation of outer diameter and wall thickness
Unit: millimeter
| Nominal outside diameter D | Allowable deviation of outer diameter | Permissible deviation of wall thickness |
| D≤48.3 | ±0.50 | ±10%S |
| 48.3<D≤273 | ±1%D | |
| D>273 | ±0.75%D |
TABLE 2 Mechanical Property
| Grade | Tensile strength
| Lower yield strength | Elongation A% Not less than | |
| D≤168.3 | D>168.3 | |||
| Q235A,Q235B | 375 | 235 | 15 | 20 |
| Q295A,Q295B | 390 | 295 | 13 | 18 |
| Q345A,Q345B | 470 | 345 | 13 | 18 |
| Note : Tensile test arbitration time is based on longitudinal sample. | ||||
TABLE 3 Inspection items, test methods and sampling number of steel pipes
| NO | Inspection project | Sampling method and test method | Sampling quantity |
| 1 | chemical composition | GB/T 20066,GB/T 223,GB/T 4336 | One each furnace(canister) |
| 2 | Tensile test | GB/T 228,GB/T 2975 | One each batch |
| 3 | Tensile test | GB/T 241 | One by one |
| 4 | Ultrasonic examination | GB/T18256 | One by one |
| 5 | Eddy current flaw detection | GB/T 7735 | One by one |
| 6 | Bending test | GB/T 244 | Two per batch |
| 7 | Flattening test | GB/T 246 | Four each roll |
Table4 Outer Diameter,Wall Thicknes,Theoretical Weight and Test Pressure
| Norminal Outer Diameter(D)/mm | Norminal Wall Thickness(S)/mm | Theoretical Weight/(kg/m) | Test Pressure/MPa | ||
| Q235A,Q235B | Q295A,Q295B | Q345A,Q345B | |||
| 21.3 | 2.5 | 1.16 | 15 | 15 | 15 |
| 21.3 | 3 | 1.35 | 15 | 15 | 15 |
| 21.3 | 3.5 | 1.54 | 15 | 15 | 15 |
| 25 | 2.5 | 1.39 | 15 | 15 | 15 |
| 25 | 3 | 1.63 | 15 | 15 | 15 |
| 25 | 3.5 | 1.86 | 15 | 15 | 15 |
| 25 | 4 | 2.07 | 15 | 15 | 15 |
| 26.9 | 2.5 | 1.50 | 15 | 15 | 15 |
| 26.9 | 3 | 1.77 | 15 | 15 | 15 |
| 26.9 | 3.5 | 2.02 | 15 | 15 | 15 |
| 26.9 | 4 | 2.26 | 15 | 15 | 15 |
| 31.8 | 2.5 | 1.81 | 15 | 15 | 15 |
| 31.8 | 3 | 2.13 | 15 | 15 | 15 |
| 31.8 | 3.5 | 2.44 | 15 | 15 | 15 |
| 31.8 | 4 | 2.74 | 15 | 15 | 15 |
| 33.7 | 2.5 | 1.92 | 15 | 15 | 15 |
| 33.7 | 3 | 2.27 | 15 | 15 | 15 |
| 33.7 | 3.5 | 2.61 | 15 | 15 | 15 |
| 33.7 | 4 | 2.93 | 15 | 15 | 15 |
| 38 | 2.5 | 2.19 | 15 | 15 | 15 |
| 38 | 3 | 2.59 | 15 | 15 | 15 |
| 38 | 3.5 | 2.98 | 15 | 15 | 15 |
| 38 | 4 | 3.35 | 15 | 15 | 15 |
| 40 | 2.5 | 2.31 | 15 | 15 | 15 |
| 40 | 3 | 2.74 | 15 | 15 | 15 |
| 40 | 3.5 | 3.15 | 15 | 15 | 15 |
| 40 | 4 | 3.55 | 15 | 15 | 15 |
| 42.4 | 2.5 | 2.46 | 15 | 15 | 15 |
| 42.4 | 3 | 2.91 | 15 | 15 | 15 |
| 42.4 | 3.5 | 3.36 | 15 | 15 | 15 |
| 42.4 | 4 | 3.79 | 15 | 15 | 15 |
| 48.3 | 2.5 | 2.82 | 14.6 | 15 | 15 |
| 48.3 | 3 | 3.35 | 15 | 15 | 15 |
| 48.3 | 3.5 | 3.87 | 15 | 15 | 15 |
| 48.3 | 4 | 4.37 | 15 | 15 | 15 |
| 51 | 2.5 | 2.99 | 13.8 | 15 | 15 |
