In mid-March, our company received an urgent procurement request from an equipment manufacturer. Due to maintenance work on Great Wall Energy’s recirculating gas cooler, 40 U-tubes were urgently needed, complying with the GB/T6479-2013 & NB/T47019-2021 standards. The requirements included:

• Material: Q345D

• Specifications: 19×5×L=4400mm

• Wall thickness tolerance: 0~+0.5mm

• Minimum bending radius: R°=40mm

• Each U-tube had to undergo a 52MPa/10S hydrostatic test

• Post-processing: Cutting 200mm blind zones from both ends

• Delivery deadline: Only 20 days

This order posed multiple challenges:

• Small batch size (difficult heat treatment)

• Tight bend radius (R≈2D)

• Small-diameter, ultra-thick-walled tubes (wall thickness-to-outer diameter ratio exceeding 0.28)

• Ultra-high pressure resistance (52MPa)

To meet these demands, we conducted a comprehensive assessment of technical specifications, standard requirements, and equipment limitations. We meticulously reviewed and confirmed every step—from piercing and heat treatment processes to mold design and trial bending—overcoming numerous difficulties in small-batch customization.

The final U-bend tubes met all performance and testing requirements, and we successfully delivered them within the 20-day deadline, helping the customer secure more time for equipment manufacturing.