EN10219 S235 straight seam welded steel pipe passes the process performance test

The EN10219 standard, the core European specification for cold-formed welded hollow sections for structural use, sets stringent requirements for the process performance testing of S235 straight seam welded steel pipe. From flattening tests to bend tests, from flaring tests to hydraulic tests, each inspection step focuses on "safe load-bearing" and "stable operation," ensuring the welded steel pipe's reliable performance in applications such as construction, bridges, and machinery manufacturing.

According to the EN10219 standard, S235 straight seam welded steel pipe with an outer diameter greater than 60.3mm must undergo a flattening test. During this test, the specimen is placed between two parallel platens and gradually compressed to a specific distance (for example, welded steel pipes with a yield strength ≥345 MPa must be compressed to 3/4 of the outer diameter). During this process, the weld seam is positioned at both 90° and 0° relative to the direction of force, respectively, to fully test the crack resistance of the weld and the parent material.

In one project, a batch of S235 straight-seam welded steel pipes performed exceptionally well in a flattening test: when the compression plate distance was compressed to two-thirds of the outer diameter, no cracks or delamination were observed. Further compression to one-third of the outer diameter resulted in only slight deformation of the base metal on either side of the weld, which did not affect the overall structural integrity. This result demonstrates that the welded steel pipes meet the ductility testing requirements of EN10219 and can withstand deformation under extreme operating conditions without failure.

For S235 straight-seam welded steel pipes with an outer diameter of 60.3 mm or less, a bend test is an effective alternative to the flattening test. In this test, the pipes are cold-bent through a 90° angle with a bend radius of six times the outer diameter, with the weld located on the outer side of the bend. This design simulates actual bending scenarios encountered during pipe installation, such as localized deformation when passing through walls or equipment.

In a bridge construction project, S235 straight-seam welded steel pipes were used as support structures. In a bending test, a 50mm diameter welded steel pipe was bent to a 300mm radius with a continuous weld seam without any fractures. Only slight wrinkles appeared on the parent material surface, which did not affect the tightness of the fluid transport within the pipe. This performance demonstrates the adaptability of the welded steel pipe in complex installation environments and provides a double guarantee for project safety.

According to customer requirements, S235 straight seam welded steel pipe can also undergo flaring tests. During this test, a flaring tool with a top taper of 30°, 45°, or 60° expands the outer diameter of the welded steel pipe end by 6% to test the ductility of the end material and the weld's crack resistance.

The process performance testing of EN10219 S235 straight seam welded steel pipe is a comprehensive quality control campaign, encompassing materials and structures, from local to overall quality control. Each welded steel pipe undergoes five levels of testing before entering the market: ductility verification through flattening tests, flexibility assessment through bending tests, end strength testing through flaring tests, sealing assessment through hydraulic tests, and internal defect screening through non-destructive testing. This rigorous inspection system is not only a faithful implementation of European standards, but also a solemn commitment to project safety and life and property.