Recently we received an inquiry of the large-dimension line steel pipe from an old client,he ordered once the same steel pipe last year.
The size of the steel pipe from 24″ to 42″ in the inquiry,the pipe welding methods given by the client include submerged arc welding length(SAWL),submerged arc welding helix(SAWH),High Frequency Welding(HFW).
Then compare the difference between these three welding methods below:
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Compare HFW / SAWH / SAWL |
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| ITEM | HFW | SAWH | SAWL | |
| Process of producing | Raw material | Hot rolled steel coil | Hot rolled steel coil | Hot rolled plate cutting |
| The width of the steel plate | 3.14D+allowance | 0.8~3D | 3.14D+allowance | |
| Process of producing pipes | continuous | continuous | Discontinuous | |
| The way of welded | HFW Pressure Welding | SAW fusion welding | SAW fusion welding | |
| Welding metal | No filler | filler | filler | |
| Treatment of welds | Heat treatment | Welded state | Welded state | |
| Fix the dimension | Full length fixed dimension | Generally no fixed/expand dimension | Full length fixed dimension | |
| Repair welding | Generally not allowed | Welds allow repair welding | Welds allow repair welding | |
| Production | chemical composition | higher alloy content | Lower alloy content | Lower alloy content |
| strength | Really reflect the pressure ability | Form an angle with the hoop stress | Really reflect the pressure ability | |
| toughness | good | Heat affected area will be low | Heat affected area will be low | |
| Dimensional accuracy | excellent | OK | Good | |
| surface | excellent | Good | Good | |
| Weld length | L | 1.047~3.925L | L | |
| Weld height | Within 0.5mm | Within 3mm | Within 3mm | |
| Residual stress | Small | large | Small | |
| Using | Hot and cold bends | Optional | Usually not used | prior choice |
| coating | Very convenient | convenient | convenient | |
| Ring welding | Very convenient | convenient | Very convenient | |
| Weld seam pressure | Actual hoop stress | Actual hoop stress component + shear stress component | Actual hoop stress | |
| Hydromechanics | excellent | good | excellent | |
| OD range | 219.1~559mm | 457~1626 mm | 457~1422 mm | |
| Wall thickness range | 4.0~19.1 mm | 6.4~22.2 mm | 6.4~38.1 mm | |
| Highest grade | X70 | X80 | X80 | |
| Supply ability | Very strong | Weaker | Stronger | |
| Note:
The type of steel pipe used in the pipeline should be determined according to the characteristics of the steel pipe,working conditions and use environment; Bends usually use seamless(SMLS) HFW or SAWL. |
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We can supply all welding types steel pipes,if you are interested in our products,please feel free to contact us,Email:sales@haihaogroup.com
