Q355B Electric Welded Pipe
Q355B Submerged Arc Welded Pipe Product Introduction
Q355B electric welded pipe is a straight seam welded steel pipe manufactured using electric arc welding (mainly submerged arc welding). Its base material is Q355B low-alloy high-strength structural steel, as specified in Chinese standard GB/T 1591-2018. This product is renowned for its excellent structural strength, good low-temperature toughness, reliable welding quality, and ability to manufacture large-diameter, thick-walled pipes, making it one of the preferred materials for heavy structures and pressure pipelines.
Mechanical Properties Table of Q355B Electric Welded Pipe
| Performance Indicators | 钢材厚度 (t) / 直径 (d) (mm) | 规定值 |
|---|---|---|
| Yield Strength (ReH) | t ≤ 16 | ≥ 355 MPa |
| 16 < t ≤ 40 | ≥ 345 MPa | |
| 40 < t ≤ 63 | ≥ 335 MPa | |
| 63 < t ≤ 80 | ≥ 325 MPa | |
| 80 < t ≤ 100 | ≥ 315 MPa | |
| 100 < t ≤ 150 | ≥ 295 MPa | |
| Tensile Strength (Rm) | t ≤ 40 | 470 - 630 MPa |
| 40 < t ≤ 100 | 470 - 630 MPa | |
| 100 < t ≤ 150 | 450 - 600 MPa | |
| Elongation after Fracture (A) | t ≤ 40 | ≥ 20 % |
| 40 < t ≤ 63 | ≥ 20 % | |
| 63 < t ≤ 100 | ≥ 19 % | |
| 100 < t ≤ 150 | ≥ 18 % | |
| Impact Energy (kV₂) | ≥ 34 J | 试验温度： +20°C |
Manufacturing Process of Q355B Electric Welded Pipe (Submerged Arc Welding)
The core process of Q355B electric welded pipe begins with high-quality steel plates. After milling pretreatment, the plates are gradually pressed into open "O"-shaped pipes using JCOE-type cold bending forming technology. Subsequently, the pipes are pre-welded using gas shielded welding to firmly connect the closed longitudinal seams. Next comes the crucial internal and external double-sided submerged arc welding, where the high temperature of the electric arc under the flux layer fuses the weld seam with the base material, forming a dense, high-strength main weld seam. After welding, the steel pipe must undergo the essential process of mechanical diameter expansion to relieve stress, accurately shape, and inspect the overall quality of the weld seam. Finally, through fixed-length cutting, rigorous non-destructive testing, and hydrostatic testing, the performance and reliability of each Q355B electric welded pipe are ensured.
About us
As a professional steel exporter, we understand the key applications of Q355B welded pipe in high-end projects worldwide. Through strategic partnerships with top domestic steel mills, we can not only reliably supply a full range of products, from thin-walled high-frequency welded pipes to thick-walled submerged arc welded pipes, but also provide precise material matching and customized processing services based on the standards and working conditions of your project location, ensuring seamless product integration with your needs.
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