Induction heating for hot forging of stainless steel

Application: Forging & Hot Forming 

Application Objectives: A manufacturing company is looking to replace an old induction generator with a new one for better efficiency, productivity, and safety.  They are heating big range of parts and materials – from 1 ½ up to 4”. 

Goals: 

• Achieve a maximum temperature of 2000°F. 

• Ensure temperature uniformity and quality in a continuous duty cycle. 

• Verify results with application tests using the SmartPower™ modular system. 

Industry: Manufacturing 

Equipment: SmartPower™: 2 modules, 25kW each, Heat station model: HS100M, Fixtures, Temperature controllers, IR pyrometers 

Materials: stainless steel cylinder 4” outer diameter and 4” height 

Time range: from 40 sec up to 3-4 min in a continuous duty

Process: 

For meeting the requirement of temperature uniformity and limitations two temperature controllers were used to track temperature on the surface of the sample and the temperature on the middle of the sample are controlled correctly during the heating process. The system is finely tuned with a set point of 2000°F. It’s designed to modulate the power output intelligently. Once the part’s outer diameter hits this high temperature, the system dials back the power, allowing the inner core of the part to catch up and reach the same temperature. The test progress was observed via the temperature graph. This graph should serve as a visual representation of the time it takes for the part to achieve a uniform temperature of 2000°F throughout.  

About six minutes into the cycle, we’ve observed that the temperature rise is plateauing, suggesting that the part is nearing a state of thermal equilibrium. To reach our target temperature of 2000°F right at the heart of the part, it’s clear we need to inject more power into the system. 

Results and Conclusions:  

• A 50kW SmartPower™ system can heat the surface to 2000°F in 1 minute and 40 seconds at 81% power. 

• If the power is increased to 100%, the heating time decreases to 1 minute and 25 seconds. 

• The center of the part reaches 2000°F in approximately 6 minutes if the surface temperature is limited to 2000°F, and about 5 minutes if the surface temperature is allowed to reach 2200°F. 

 Reference Info: AR 3463-7553