Pre-welding precautions
Saemin, a manufacturer of butt welding machines with over 35 years of experience, has consistently developed and upgraded its equipment to the highest international standards. Based on the DVS2207-1 standard and numerous tests, we share the following information with all butt welding machine users:
If the semi-finished product is unevenly heated under sunlight, temperature compensation in the weld joint area can be achieved through covering. Cooling through ventilation should be avoided during welding; for example, the pipe ends should be closed during welding.
Pipes from colls are oval immediately after uncoiling. The pipe end must be prepared before welding,
e. g. by careful heating upwith a hot-air equipment and use of a suitable clamping and/or rerounding device.
The connection zones of the components to be welded must beundamaged and have to be free of contaminations.
The centering gap before pipe welding is shown in the table below
| Pipe outer diameter (mm) | Centering Gap(mm) |
|
≤355 |
0.5 |
|
400~630(excluding) |
1.0 |
|
630~800(excluding) |
1.3 |
|
800~1000(inclusive) |
1.5 |
|
＞1000 |
2.0 |
Heating Plate Temperature (HDPE100 material)
Welding Process Diagram
Wall Thicknes(mm) |
Interface Pressure Coefficient(calculated at 0.15 N/mm² ± 0.01)(mm) |
Heat Absorption Time
|
Switching Time(S) |
Pressure Increase Time(S) |
Cooling Time(Min) |
|
＜4.5 |
0.5 |
＜45 |
5 |
5 |
6 |
|
4.5~7 |
1.0 |
45~70 |
5~6 |
5~6 |
6~10 |
|
7~12 |
1.5 |
70~120 |
6~8 |
6~8 |
10~16 |
|
12~19 |
2.0 |
120~190 |
8~10 |
8~11 |
16~24 |
|
19~26 |
2.5 |
190~260 |
10~12 |
11~14 |
24~32 |
|
26~37 |
3.0 |
260~370 |
12~16 |
14~19 |
32~45 |
|
37~50 |
3.5 |
370~500 |
16~20 |
19~25 |
45~60 |
|
50~70 |
4.0 |
500~700 |
20~25 |
25~35 |
60~80 |
Note
Flanging pressure, butt joint pressure, and cooling pressure are all calculated at 0.15 N/mm² ± 0.01.
Heat absorption pressure is calculated at less than 0.01 N/mm² but not equal to 0.
All pressure values should include drag pressure.
years experience
Utility model patent
Global customers
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Conclusion The core of HDPE fusion is "equipment adapted to operating conditions and parameters conforming to standards. " Saemin's full range of equipment, combined with standardized processes and in accordance with ISO, DVS, and ASTM standards, enables high-quality fusion of multiple fields and materials, providing long-term support for engineering piping systems. |
In the next chapter, we will share PP pipe Welding Times