Q235B DN250 Large Diameter Spiral Welded Pipe

DN250 spiral steel pipe will send the strip into the welding pipe unit, roll through the multi-channel roll, the strip gradually rolled up to form a circular tube blank with an open gap, adjust the pressure of the extrusion roll, so that the weld gap is controlled in 1~3mm, and make the welding ends flush. If the gap is too large, the proximity effect is reduced, the eddy heat is insufficient, and the weld crystal is not fused or cracked indirectly. If the gap is too small, the proximity effect will increase, and the welding heat will be too large, resulting in burning of the weld. Or the weld formed deep pits after extrusion and rolling, affecting the surface quality of the weld. After the two edges of the tube blank are heated to the welding temperature, under the extrusion roll, the common metal grains penetrate and crystallize with each other, and finally form a firm weld.

If the extrusion pressure of the DN250 spiral steel pipe is too small, the number of common crystals will be small, the strength of the weld metal will decrease, and the cracking will occur after the stress. If the extrusion pressure is too large, the molten metal will be extruded from the weld, which will not only reduce the strength of the weld, but also produce a large number of internal and external burrs, and even cause defects such as welding joints.

FAQ：

1.Can I get samples before order?
Yes, of course. Usually, our samples are free. we can produce your samples or technical drawings, all you need to pay is the shipping cost to you. We can build moulds and fixtures so we can customize our products based on your demand.

2. what is your delivery time?
It mainly depends on your location and demanded volume. The time of delivery is usually around 2 weeks.
We can send it out in 2 days if it has stock.

3.What is your payment terms?
Our usual payment term is 30% deposit and the rest against B/L. L/C is also acceptable. And the shipping terms are EXW, FOB, CFR, CIF and DDU. Whichever you like.

4. How can you guarantee the quality of my goods?
We are a factory with 100% pre-delivery inspection which guarantee the quality.

5. How do you make our business long-term and good relationship?
1. We keep good quality and competitive price to ensure our customers benefit ;
2. We respect every customer and we sincerely do business with them, sustain our service level before and after every deal.

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