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Hebei haihao high pressure flange & pipe fitting group was established in 1982, located in Mengcun County the hometown of pipe fittings in China.

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Comparison of SAWL / SAWH / HFW Welding Methods

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:

Compare 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

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.

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


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