Hot Heading a Steel Wire to Create a Screw

Hot Heading a Steel Wire to Create a Screw

Objective: Preheating steel wire before hot heading to create a screw; they wanted to switch from cold heading to extend tool life.

Equipment: Ambrell EKOHEATⓇ 30 kW, 50-150 kHz solid state induction power supply with a workhead and coil specifically designed for this application.

Frequency: 94 kHz

Material: Steel wire (0.214” / 5.4 mm diameter)

Temperature: 350 °F (177 °C)

Testing:

• A custom-designed single position multiple-turn helical coil was built by THE LAB for this application. Initial tests were conducted to optimize the power delivered to the part. Temperature indicating paint was then applied to the part, which dissolves when it reaches the target temperature. A thermocouple was used for this application.
• The power was turned on for 0.5 seconds, which simulates the customer run rate. Temperature was monitored during heating as well as cooling. It was observed that the wire heated well to maintain the target temperature after 3 seconds, which is the time required for the wire to travel from the induction coil to the cutoff location.

Benefits:

• Speed: Induction met the client’s time requirements and is generally faster than other heating methods.
• Throughput: Induction’s fast heating is conducive to production lines like those in the fastener industry. 
• Repeatability: The client can expect the same result in the same amount of time every single time with induction heating.