The Growing Demand to Bend P91 Pipe for New Power Plants
By the end of this decade, an estimated 300 to 400 new power plants will be built worldwide. Much of the pipe carrying high-pressure steam to turbines is now made from a newer-grade chromium-molybdenum alloy, 9% Cr-1Mo-V (P91) steel. This advanced material offers a better strength-to-weight ratio than the older 2¼% Cr-1Mo (P22) steel. Due to its higher chrome content, P91 is stronger and more wear-resistant than P22, making it ideal for projects that require precise bending solutions to bend P91 pipe effectively.
A 26-inch-diameter main steam line made from P91 can have a wall thickness of 2¼ in. With P22, you’d be looking at a product almost 5 in thick. Therefore, designers choose this material.
With the Inductaflex machine it is specifically designed to handle this material and guarantee a quality bend every time to the standards imposed by the power generation industry.
Advanced Temperature Monitoring for Precise Bends
Features like a third pyrometer read the inside temperature of the pipe during the critical “soak through period” before starting the bend. This is crucial because the bend temperature throughout the wall thickness of P91 material must be precisely controlled. Most induction bending machines operate at a preferred frequency of 1000 Hz. At this frequency, the “reference depth” — how deeply the electromagnetic field penetrates the material — is about 0.7” (17.8mm). Beyond that depth, the machine relies on thermal conductivity during the soak through period to evenly heat the pipe.
3-Axis Control to Minimize Wall Thinning
Moreover, the 3-axis control of the inductor coil ensures the tangent area of the pipe undergoes consistent heating throughout the bend. The coil’s movement in the X and Y axes helps minimize wall thinning, while maintaining the pipe’s ovality within industry standards.
Inductaflex also offers accurate pipe temperature control throughout the bend via 2 additional pyrometers. This ensure the material chemical properties are controlled and a constant temperature over the full length of the bend. All-important records are stored in the machine so that the customer gets full documentation of the bending process.
“With Inductaflex, you get more than just a machine, you get our expertise in handling & bending and any kind of material to customer’s specifications”
Data Sheets
We can provide procedures for an array of materials through our years of experience and testing. Our data sheets include;
- Storage of the material
- Record keeping and full tractability of Induction Bent pipe.
- Handling material
- Contamination procedure for induction bending machines.
- Pre-bending checks
- Bending the material
- Post bending checks, none destructive testing procedures
- Post bending Heat treatment P91
- Packaging
- Supporting documentation
