Welded 3D Pipe Bend Manufacturer

 Welded 3D Pipe Bend Manufacturer

As a professional welded 3D pipe bend manufacturer, Hebei Longrun Pipeline Group Company provides engineered solutions designed for fluid transportation systems that require smooth directional changes, reliable pressure performance, and stable long-term operation. Welded 3D pipe bends are widely used in industries including petrochemical processing, thermal power generation, shipbuilding, and large-scale water distribution. Their 3D geometry—where the centerline bend radius is three times the nominal pipe diameter—offers optimized flow behavior and reduced turbulence, making them a preferred choice for high-efficiency piping systems.

Raw Material Standards and Metallurgical Requirements

The production of welded 3D pipe bends begins with the selection of high-quality steel plates or pipes that conform to ASTM, ASME, GB, and EN specifications. Materials typically include carbon steel, low-alloy steel, and stainless steel grades, depending on the service medium and operating environment. Before fabrication, materials undergo chemical composition testing to verify carbon, manganese, silicon, sulfur, and phosphorus contents. Ensuring proper metallurgy is essential for achieving required mechanical properties such as tensile strength, elongation, impact resistance, and weldability.

Nondestructive testing—including ultrasonic inspection and magnetic particle testing—is conducted on raw materials to detect inclusions, laminations, and surface imperfections. Only materials that pass these evaluations progress to the bending and welding stages.

Forming Process of 3D Pipe Bends

Welded 3D pipe bends can be produced using different forming methods depending on diameter, wall thickness, and project specifications. Hebei Longrun Pipeline Group Company primarily uses two techniques:

Induction Heating and Bending

High-frequency induction coils heat a localized section of pipe to the required forging temperature.

As the pipe advances through the induction zone, bending equipment gradually forms the 3D radius.

The process ensures continuous fiber structure and uniform deformation.

Segmented Pipe Welding and Fabrication

For large diameters or special wall thicknesses, multiple pipe segments are cut at precise angles.

Each segment is welded using qualified welding procedures (SMAW, GTAW, FCAW, or SAW).

This method ensures dimensional accuracy for bends where single-piece induction bending is impractical.

Throughout forming, parameters such as heating rate, bending speed, and mandrel support are controlled electronically to ensure a smooth internal surface and consistent wall thickness.

Welding, Heat Treatment, and Stress Relieving

Welding procedures for 3D pipe bends are qualified according to ASME IX, ISO 15614, or relevant standards. Welders are certified and experienced in handling carbon steel, alloy steel, and stainless steel materials. Welding joints undergo root pass inspection and interpass cleaning to prevent slag inclusion or porosity.

After forming and welding, heat treatment is applied when required:

Normalizing improves uniformity for carbon steel.

Quenching and Tempering enhances yield strength and toughness for alloy steels.

Solution Annealing stabilizes stainless steel microstructure and prevents sensitization.

Post-weld heat treatment reduces residual stresses to increase structural reliability under pressure cycling.

Dimensional Accuracy and Machining

Precision machining ensures that all bends meet strict tolerances for:

Ovality

Wall thinning

Centerline radius accuracy

End-to-end alignment

Bevel dimensions for welding installation

Automated measurement systems record all geometric data, contributing to complete documentation for end users.

Surface Treatment and Corrosion Protection

Welded 3D pipe bends can be finished with:

Shot blasting to SA 2.5 cleanliness level

Epoxy primer coatings

High-temperature coatings for refinery applications

Polyurethane or FBE coatings for buried pipelines

Pickling and passivation for stainless steel

These surface protections extend service life in corrosive and high-humidity environments.

Quality Control and Inspection Protocols

Quality control follows ISO 9001 quality management requirements. Inspection includes:

Dimensional checks using laser and caliper systems

Radiographic or ultrasonic testing on welds

Hardness measurement

Hydrostatic pressure tests

Positive material identification (PMI)

Visual examination according to ASME B31.3 or B16.49 requirements

All products include traceability files, heat numbers, test certificates, and inspection reports.

Application Fields and Performance Characteristics

Welded 3D pipe bends manufactured by Hebei Longrun Pipeline Group Company serve in:

Petrochemical pipelines

Refined product transport systems

Chemical processing plants

Thermal power stations

Offshore and marine piping

Long-distance water transmission

Their smooth curvature minimizes pressure drops, protects pump efficiency, and reduces erosion effects caused by turbulent flow.