Everything You Need to Know About Controlling Your Kiln

Guide to Choosing a Heat Treating Controller Blog Header Image
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Scott Shannon

Guide to Choosing Heat Treating Controllers

When it comes to heat treatment, precision and stability are key. Heat treating controllers ensure that you’re able to precisely control the temperature of your oven or furnace throughout each stage of the heat treat process. 

Why is this important? Whether you’re making knives, swords, or industrial components, correct temperature and soak time determine whether your metalwork has the intended properties.

Definition of Heat Treatment

Before getting into the ins-and-outs of heat treating controllers, let’s define heat treatment and explore common types of heat treatments.

Heat treatment is a process of heating and cooling metals and alloys in a controlled manner to alter their physical and mechanical properties, such as hardness, ductility, malleability, temperature resistance, and material strength. Heat treatment has a wide range of applications and is used for everything from making knives or other simple tools to building aerospace components! 

Stages of Heat Treat

At an extremely high level, every type of heat treatment involves 3 main stages:

  • Heating: Heating the metal or alloy to a specific temperature, ensuring that it heats evenly.
  • Soaking (or Holding): Keeping the metal at temp for a specific period of time.
  • Cooling: Bringing the metal or alloy back to room temperature. 

Depending on the application and the desired properties of the metal, these stages may be repeated multiple times or may have specific requirements regarding Ramp Rate (how quickly the metal is brought to temp) or Cooling Rate (how quickly the metal is cooled to room temperature).

Common Methods of Heat Treatment

Below are common heat treating methods, as well as the effects they have on the metal:

  • Normalizing: The metal is heated to an extremely high temperature for a defined period of time and then air-cooled. Normalizing relieves internal stress and ensures uniformity, resulting in harder, stronger metals.
  • Annealing: The metal is heated beyond the upper critical temperature and then slowly cooled to soften it and increase its workability. Annealing increases ductility and toughness, while relieving stress, making the metal more resistant to fractures.
  • Hardening: The metal is heated until it forms an even solution and then allowed to cool to increase its hardness. 
  • Case Hardening: Only the outside of the metal is hardened, creating a durable outer layer while ensuring the metal retains flexibility and doesn’t become brittle.
  • Quench Hardening: After heating, the metal is cooled rapidly by dipping it into an oil, polymer, or water, resulting in very hard, very brittle metal.
  • Tempering: After hardening, the metal is heated to a lower temperature to reduce excessive hardness and relieve internal stress. Tempering makes metals less brittle.

What to Look for in a Heat Treating Controller

Regardless of the application, when choosing a heat treating controller for your kiln or oven it’s important to look for 3 main features:

  • Precision: Since temperature dictates the properties of the metal, it’s important to select a heat treating controller that precisely controls the temperature of your kiln or oven. PID (Proportional Integral-Derivative) controllers, such as the TAP Digital Controllers from SDS Industries, will result in the highest degree of precision, making them ideal for heat treatment.
  • Reliability: Consistency and stability are important considerations when buying a heat treating controller. High quality components, onboard diagnostics to verify input/output, energy-efficient design, and preventative maintenance alerts ensure reliability and consistent results.
  • Ease-of-Use: In 2023, heat treating controllers should make life easy for metalworkers, whether you do your heat treatments at home or in an industrial setting. The best digital controllers include touchscreen controls, mobile app integration, alerts, alarms, and the ability to create, name, and save unlimited schedules.
TAP II Heat Treating Controller
The TAP II Controller by SDS Industries is the most advanced, easy-to-use heat treating controller on the market today.



Single Setpoint vs Multi-Setpoint

Another consideration is whether you should purchase a Single Setpoint or a Multi-Setpoint controller. A Single Setpoint controller allows you to set your oven to a single temperature for an indefinite amount of time. For heat treatments that don’t require specific Ramp Rates, Single Setpoint controllers are often a more affordable option.

However, some heat treatments require specific Ramp Rates and multiple Setpoints, in which case you should choose a Multi-Setpoint controller. The TAP II Controller, which is the most advanced heat treating controller on the market, allows metal workers to create an unlimited number of Setpoints and Ramp Rates and save an unlimited number of schedules, making it ideal for complex heat treatments. (It’s also worth noting that Multi-Setpoint controllers are capable of Single Setpoint applications).

Coming Soon: TAP&Go

We at SDS Industries are excited to announce the TAP&Go Kiln Controller. Our most simplified control option yet, the TAP&Go is a Single Setpoint controller, making it ideal for heat treat, knife-making, or for users who don’t need to execute complex firings.

TAP&Go is built on a modular platform that will allow users to purchase add-ons like a 2.4” Capacitive Touchscreen, and Output Adapter, or an Input Power Adapter that snap right onto the Controller Board! TAP&Go is controlled almost entirely through the TAP Kiln Control Mobile app, making it a convenient and affordable heat treating controller.

With development and testing well underway, the TAP&Go is on track for release in the coming months. Make sure to subscribe to SDS Industries to learn more!

Choose the Heat Treating Controller That’s Right For You

If you’re in the market for a heat treating controller, the TAP and TAP II Controllers by SDS Industries are the most advanced, precise, and easy-to-use controllers on the market today. We invite you to explore our selection of digital controllers, standalones, and conversion kits on our online store. Or you can purchase TAP Digital Controllers or TAP-Controlled Heat Treat ovens through one of the following distributors:

CTA Choose TAP Controllers for Heat Treat


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