This week we finish up our introduction to the basic questions you need to answer when designing your heat treating solution. Once you have your material, your hardness level, and the geometric requirements, now you need to look at materials handling and facilities.

Parts that are typically flame hardened tend to weigh hundreds of pounds. People aren’t going to pick them up to load and unload them from the machine. They often use a crane to do so. Also, when using flame hardening, the positioning of the part in the machine is absolutely critical. The part is designed for a specific area to receive the heat, and if it’s positioned incorrectly you are going to introduce quality issues. Cycle time needs to include all these handling factors, plus the heating time it takes to reach the desired Austenizing temperature, and the quench time to obtain the right hardness (martensite).

For clients who want to maximize cycle time and minimize positioning errors, we often help design automatic loading and positioning solutions. Otherwise you need skilled operators willing to be trained.

When designing inhouse applications, or analyzing the cost-benefit of inhouse versus outsourcing, you need to know the size of the footprint of the heat treating equipment. The size of the parts being hardened is the largest determinant of the machine’s footprint, as is the production rate of the hardening line. It’s also determined by your procedural sensibilities. Some clients want machines siphoned off into a separate room. Others want the machines in the same room as the other production line equipment. Our flame hardening machines have fit in a ten by ten space, and others required a space twenty by twenty. Since our machines do not produce carbon monoxide or any poisonous gas, they don’t require any outside venting. A hood can be installed to pull any secondary heat out of the room, or to pull away any steam that might be generated during the quench.

Flame hardening machines use fuel gas and oxygen to produce the heat; induction uses electricity. Fuel gases include natural gas, propane, and an industrial gas such as propylene. For operation, flame hardening machines require natural gas at pressures of 20 psi and higher. You can ask utility companies to provide this pressure for you, or use a booster pump to boost the pressure at the machine. For propane and industrial gases, getting the delivery pressure @20 psi or higher is not an issue.

The delivery system of oxygen depends on the type of application. You can get oxygen in cylinders, liquid, or liquid bulk. The volume of parts run through the machine will determine which delivery system makes sense for your application.

Flame hardening machines also often require compressed air, but a standard air compressor is usually sufficient. The electrical requirements are usually typical standard industrial levels of 480, three phase. The electrical is used mainly for controls and pumps, so your actual amperage is not that high (as opposed to induction, which uses much more electricity to generate heat treating and therefore that utility cost needs to be factored into the budget). Oxygen and fuel gas make up the bulk of the operating costs for flame hardening equipment.

Next week we’ll talk more about how to determine whether to send your parts to a flame hardening shop or bring the process inhouse. As always, if you have any questions about designing your heat treating solution, email me at mark@flametreatingsystems.com or call 919-956-5208.

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