As demand for high-strength rectangular and square structural tubes continues to grow in construction, machinery, and steel fabrication industries, manufacturers are seeking more stable and efficient heat-treatment solutions. To address these needs, Yuantuo Electromechanical Equipment Manufacturing Co., Ltd. has introduced a fully customized Rectangular & Square Tube Quenching Line, designed specifically to overcome the unique heating challenges associated with non-round tube profiles.

1. Technical Challenges of Heat-Treating Rectangular Tubes

Due to their asymmetric geometry and varying surface widths, rectangular and square tubes are prone to multiple heat-treatment issues:

• Uneven heating leading to hardness variation

• Faster temperature rise at corners

• Higher risk of bending during quenching

• Inconsistent movement causing positional drift

• Difficulty maintaining stable production rhythm

These challenges require a dedicated solution — not simply adapting round-tube heat-treatment equipment.

2. Yuantuo’s Rectangular Tube Quenching Line: Engineered for Precision and Stability

Yuantuo’s new system implements a modular and fully customized design, covering material feeding, uniform induction heating, controlled quenching, and shape-stabilizing cooling.

• Dual-Pinch-Roll Synchronous Drive Ensures Straight and Stable Movement

Rectangular tubes often change posture or tilt on conventional roller tables.
Yuantuo solves this with:

• Dual pinch rolls

• Strong clamping force

• Synchronous drive control

This stabilizes tube movement, prevents runout, and minimizes deformation during quenching.

• Custom Induction Coils for Uniform Four-Side Heating

Because the four sides of a rectangular tube differ in width, magnetic-field distribution tends to be uneven.
Yuantuo addresses this through:

• Custom rectangular induction coils

• Corner-field compensation design

• Optimized magnetic-yoke structure

• Improved thermal uniformity and energy efficiency

Temperature deviation can be controlled within ±5–10°C, ensuring stable mechanical properties.

• High-Precision Quenching System to Maintain Shape and Metallurgical Structure

The quenching module features:

• Adjustable spray-cooling layout

• Multi-zone flow-pressure control

• Reduced thermal shock to prevent local distortion

• Controlled cooling rates for metallurgical stability

This ensures consistent hardness and improved toughness.

• PLC + Infrared Closed-Loop Temperature Control

The entire line integrates:

• PLC automatic control

• Infrared temperature measurement

• Data logging & recipe management

• Real-time power adjustment

Ensuring repeatable, traceable, and highly automated process control.

3. Broad Application Range Across Industries

The system is suitable for:

• Rectangular structural tubes

• Square tubes

• Machinery arms and boom structures

• Conveyor frame tubes

• Special steel sections

Compatible with carbon steel, alloy steel, and high-strength low-alloy steels such as Q355 and Q460.

4. Proven Improvements in Customer Production Lines

Manufacturers using Yuantuo’s rectangular tube quenching line report:

• More uniform hardness distribution

• Reduced corner overheating and scale formation

• Lower bending rate after quenching

• More stable production cycle

• Better control of product quality and repeatability

These improvements significantly reduce rework and improve overall efficiency.

Rectangular and square tubes require heat-treatment equipment specifically engineered for non-round profiles.
With dual-pinch-roll drive, customized coil design, magnetic-field optimization, and intelligent control, Yuantuo provides a mature, reliable, and high-performance quenching solution for structural tube manufacturing.

Yuantuo remains committed to advancing induction-heating technology and delivering stable, efficient, and automated heat-treatment solutions for global metal-processing industries.