Induction Annealing of Steel Parts

Objective: A new customer who works in the manufacturing industry wants to start using induction heating technology. They are interested in the combination of induction preheating and following induction annealing applications.

The client sent us two metal tubes for application testing. The large tube is mild steel (L150mm, OD16mm, ID10mm), and the small one is a nickel alloy (L 121mm, OD8mm, ID 4mm). The tubes are made of two parts split through the middle of the length.

We must preheat 20mm from the total length of tubes to 450°C for 7-8 seconds and then hold the temperature for 20 seconds. This cycle will repeat approx once per minute.

The main goal is to achieve uniformity in the zone of heating and good temperature control during the temperature hold. We also have to test is it possible to heat both tubes with one inductor.

Industry: Manufacturing & Automation

Equipment: For this application test was used UltraHeat S – 2kW Induction Heater with two different C-shape induction coils.

Process: During the tests, we confirmed that the 2kW system is suitable for the application and we were able to reach the desired heating cycles. For the smaller tube, a heating profile was prepared for repeatable processes. The preheating was for ~7 seconds separate on two steps. A heating profile can be made for the bigger tube too. For this part, we successfully reached 8 seconds for preheating.

We used a tempilaq pain to confirm the required temperature. The temperature hold was established by keeping the paint in its liquid form, which means that the temperature was at least 427°C.

Our conclusion and strong recommendation are to use different coils for each tube. A more suitable coil can be designed that will complement the uniform heating.

Benefits: With induction heating is much easier to reach and hold power, temperature, and time that need for the applications. Increasing energy efficiency, productivity rate, and future automation are some of the other advantages.

Reference Info: Application Note 3464-7184

Read more about other induction annealing applications.

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