Induction Bending Elbow

Induction Bending Elbow is a high-precision pipe fitting that utilizes electromagnetic induction heating technology to achieve pipe bending. Through the synergistic effect of local heating and mechanical thrust, the pipe is bent into shape under controlled conditions, and is widely used in medium and high pressure pipeline systems in industries such as petroleum, natural gas, and power. Its core advantage lies in stable bending quality, especially suitable for forming large-diameter and thick walled pipelines.

1、 Process principle

The manufacturing process of induction bending tube reflects precise thermal mechanical synergistic control:

Induction heating: Install an induction coil on the bent part of the pipe and apply high-frequency current to generate an alternating magnetic field, causing the pipe to rapidly heat up locally to the plastic range (carbon steel about 850-1000 ℃, stainless steel 1050-1200 ℃). The heating area is precisely controllable (usually 1-1.5 times the diameter of the pipe).

Mechanical bending: At the same time, axial thrust is applied to the pipe through the propulsion device, and with the guidance of the mold, the hot zone is gradually bent to a preset angle (90 °, 45 °, etc.), and the bending radius can be adjusted according to the needs (1.5D to 10D).

Cooling and shaping: After bending, it is quickly cooled by spraying water or air cooling to avoid coarse grains and ensure the mechanical properties of the bent part.

This process does not require overall heating and can minimize material oxidation and deformation. The wall thickness reduction rate at the bending part can be controlled within 10%, which is much better than traditional hot press bending.

2、 Core advantages

Excellent accuracy: bending angle deviation ≤ 0.5 °, curvature radius tolerance ≤ ± 1%, suitable for systems with strict requirements for pipeline routing (such as subsea pipelines and nuclear power plant pipelines).

Stable mechanical properties: Local heating avoids overall performance degradation, and the difference in tensile strength and impact toughness between curved parts and straight pipe sections is less than 5%. It can be directly used for high-pressure (≥ 20MPa) working conditions.

High efficiency: The molding time for a single bent pipe is only a few minutes to half an hour, suitable for mass production, especially for large-diameter (DN600 and above) pipes with significant advantages.

Wide applicability: It can process various materials such as carbon steel, stainless steel, alloy steel pipes, and even bend composite pipes welded with dissimilar steels.

3、 Specifications and Applications

The common specifications of induction bending pipes should comply with standards such as ASME B16.9 and GB/T 12459, with angles ranging from 15 ° to 180 °, bending radii from 1.5D (long radius) to 10D (customized long radius), and wall thicknesses suitable for Sch40 to XXS grades.

Typical application scenarios include:

The turning section of natural gas long-distance pipelines (large-diameter induction bends to reduce the number of welds and lower the risk of leakage);

High temperature steam pipeline of power plant boiler (12Cr1MoV material induction bend can withstand high temperature of 540 ℃);

Shallow section of submarine oil and gas pipeline (316L stainless steel induction bend pipe resistant to seawater corrosion).