How to Select the Proper Induction Hardening & Tempering Line for Steel Plates of Different Sizes and Materials

1. Selection Standards Based on Steel Plate Specifications (Thickness, Width, Length & Production Capacity)

1.1 Plate Thickness (Determines Power Supply and Inductor Structure)

1. Thin plates (2–12 mm)Adopt low-to-medium power IGBT medium-frequency power supplies and open flat transverse flux inductors. A single coil delivers uniform heating, paired with light-duty chain roller conveyors. Integrated compact QT lines feature small footprint and low investment, ideal for thin wear-resistant plates and lightweight structural steel plates used in construction machinery.
2. Medium plates (12–80 mm)Standard heavy-duty continuous QT lines with multi-section segmented induction coils and graded power ranging from 500 kW to 3000 kW. Equipped with multi-layer segmented spray quenching boxes to eliminate temperature gaps between plate surface and core. This model is the mainstream choice for shipbuilding and pressure vessel manufacturing.
   Steel plate induction hardening and tempering line
3. 
4. Extra-thick plates (80–120 mm and above)Multi-unit parallel high-power power systems with double-layer composite flux inductors and extended heating & holding sections. Reinforced load-bearing roller frames and heavy-duty transmission structures are adopted to extend tempering channels, avoiding uneven hardness and internal stress deformation inside thick plates.

1.2 Plate Width & Single Piece Length

• Narrow plates (≤1500 mm): Standard integrated universal inductors with one single coil covering the whole plate width.

• Wide plates (1500–3000 mm): Multi-group independent temperature-controlled coils with separate power adjustment for left and right zones to prevent insufficient heating on plate edges.

• Extra-long plates (＞6 m): Extended continuous roller conveying lines and segmented heating chambers to maintain stable temperature during plate transportation.

1.3 Hourly & Annual Output

• Annual output below 50,000 tons: Semi-automatic basic QT lines with single power supply and simple cooling circulation systems.

• Annual output 100,000–150,000 tons: Fully automatic 24-hour continuous production lines with dual power units, closed-loop water circulation and online hardness detection modules.

• Annual output over 200,000 tons: Dual parallel heating channels and double-station quenching & tempering units with split conveying design for high throughput.

2. Matching Equipment Configurations by Steel Material Grade

2.1 Ordinary Carbon Structural Steel (Q235, Q355)

2.2 Wear-resistant Steel Plates (NM400 / NM450 / NM500)

2.3 High-strength Alloy Steel Plates (42CrMo, 16MnDR pressure vessel steel, EH36 ship steel)

2.4 Special Alloy Thin Plates (Titanium Alloy, Low-alloy Ultra-high Strength Steel)

3. Differentiated Supporting Configuration Selection

1. Induction Power Supply

• Thin plates & ordinary carbon steel: Single standard IGBT power unit.

• Thick plates & alloy wear-resistant steel: Multi-parallel SiC energy-saving power supplies with low harmonic distortion and fast temperature response.

2. Induction Coil

• Ordinary carbon steel: Single-layer water-cooled universal coils.

• Wide & thick alloy plates: Multi-layer composite water-cooled coils with independent power regulation for each zone.

3. Quenching Cooling System

• Thin plates: Low-pressure spray cooling system.

• Thick & wear-resistant plates: Segmented adjustable high & low-pressure spray system, compatible with water-based quenching liquid switching.

4. Automation Grade

• Rough processing of carbon steel: Semi-automatic model with manual loading & unloading.

• High-end alloy plates for shipbuilding & pressure vessels: Fully automatic integrated line with auto feeding, straightening, hardness inspection and blanking.

4. Standard Selection Workflow of Forever Electromechanical

1. Submit core parameters: Plate thickness range, maximum width, single piece length and hourly processing tonnage.

2. Provide steel grade, target hardness allowable deformation and factory power supply voltage.

3. Our technical team designs matched power capacity, inductor structure and overall line length.

4. Select optional auxiliary systems including closed water circulation and waste heat recovery based on local environmental protection standards.

5. Offer three tiered solutions: Economy basic model, standard fully automatic model and high-end digital customized model with corresponding quotations.

6. 
   

5. Common Selection Mistakes to Avoid

1. Equipping thick plates with low-power single power supply: Insufficient core heating leads to layered hardness and rejected finished plates.

2. Using single-section coils for wide wear-resistant plates: Poor heating on plate edges causes excessive hardness deviation.

3. Open water circulation for alloy pressure vessel steel: Severe oxidation and decarburization fail flaw detection standards.

4. Unnecessarily low automation for alloy steel production: Manual temperature control brings large errors and unstable batch quality.