Working Principle of Long Bar Heat Treatment Machines

Long Bar Heat Treatment Machine is a specialized piece of equipment designed to enhance the mechanical properties of long metal bars through controlled heating and cooling processes. Typically, these machines are utilized in industries such as automotive manufacturing, machinery production, and aerospace, where components like shafts, rods, and bolts require precise heat treatment to achieve desired hardness, strength, and fatigue resistance.

Induction Heating Technology

Duolin’s machine uses electromagnetic induction heating, where alternating current flows through a coil to create a high-frequency electromagnetic field. When a conductive metal bar passes through this field, eddy currents are generated on its surface, producing rapid and localized heat.

Benefits:

Heating directly inside the material minimizes heat loss.

Precise temperature control avoids overheating and reduces deformation.

Heating speed can be adjusted to match material type and thickness.

Applicable materials: Carbon steel, alloy steel, stainless steel, and other ferrous metals suitable for induction heat treatment.

Automated Control System with PLC

Duolin equips its long bar heat treatment machines with advanced PLC (Programmable Logic Controller) systems to automate and optimize the heat treatment process:

Power Regulation: Dynamically adjusts induction power to maintain stable heating temperatures.

Speed Control: Controls the feed speed of the bars through the induction coil for uniform heat penetration.

Cooling Control: Manages the quenching water flow and pressure to ensure consistent and rapid cooling.

Process Monitoring: Real-time monitoring of temperature, power consumption, and system status to guarantee process stability and product quality.

This level of automation not only improves production efficiency but also significantly reduces operator error.

Quenching and Tempering Process

After induction heating, the metal bar undergoes quenching, typically via a water cooling system integrated into the machine. Rapid cooling locks the surface microstructure into a hardened state.

Quenching features:

Water cooling system with adjustable flow rates to optimize hardness and reduce thermal stress.

Optional polymer or oil quenching for specific material requirements.

Optionally, tempering can be performed afterward to relieve internal stresses and improve toughness.

Energy Efficiency and Environmental Advantages

Duolin’s machines use electricity exclusively, avoiding combustion fuels like coal or gas, resulting in:

Lower emissions and reduced environmental impact.

Minimal oxidation and decarburization due to controlled heating atmosphere.

High energy utilization efficiency because induction heating directly heats the workpiece without warming surrounding air.

Technical Specifications and Product Range

Diameter Range: Capable of processing bars from 6 mm up to 45 mm.

Heating Frequency: Machines are available with medium-frequency (MF) or high-frequency (HF) power supplies depending on application.

Power Options: Customizable induction power ranging from 40 kW to over 200 kW.

Automation: Optional motorized coil adjustment, temperature feedback sensors, and touch screen control interface.

Applications

Duolin’s Long Bar Heat Treatment Machines serve a wide range of industrial sectors:

Automotive: Shafts, axles, steering rods, and other critical components.

Machinery: Hardened bars, shafts, and tooling components.

Construction: Reinforcement bars and metal rods requiring enhanced strength.

Aerospace: Specialized components with strict hardness and wear resistance requirements.

The machines improve hardness, wear resistance, and fatigue life, contributing to better product performance and longer service life.

Duolin’s Industry Experience

Founded in 1994, Duolin has become a global leader in induction heating technology, with:

Over 30 years of research and development experience.

Thousands of installations worldwide, covering diverse heat treatment applications.

Strong focus on innovation, quality assurance, and customer service.

Duolin’s Long Bar Heat Treatment Machine is a reliable, efficient, and environmentally friendly solution for continuous heat treatment of long metal bars. Its advanced induction heating technology combined with automated control systems ensures high product quality, energy savings, and operational flexibility.