Ovens and Kilns
Shop Area: Metal Shop
Requires in-person training: No
UG 130-08, Rev. 0
KH 418 Evenheat Kiln
Chamber Dimensions: 18" Deep x 6.5" Wide x 4.25" High Max Temperature: 2200°F
Heat Treat Oven – Kiln (Evenheat) for the heat treating of metals for knife making, gunsmithing, automotive and general machine shop work.
Evenheat Knife/Heat Treat Ovens are a controlled heat source designed for the sole purpose of heat treating metals
- Never place anything under or above the oven for storage.
- Nothing should be propped against the oven.
- The surface of the oven is hot and burn injuries are possible.
- Protective clothing should be worn when operating the oven and includes, but is not limited to, cotton clothing, heat resistant gloves and eyewear capable of filtering Infrared and Ultraviolet light.
- Turn the oven’s power switch to the OFF position before accessing the oven chamber.
- Do not access the oven chamber if the ovens power switch is at the ON position.
- Never fire an oven unattended beyond its anticipated firing time. Do not operate the oven over the maximum temperature rating printed on the nameplate.
- Do not operate the oven with the door open.
- Never allow the power cord to touch the oven. If the power cord, plug or receptacle becomes damaged discontinue use and replace immediately.
- Keep the oven door closed when not in use.
- When firing is complete, and during periods of non-use, remove power from the oven by unplugging or by throwing the disconnect or breakers to the OFF position.
- KH 418 Manual (https://a9843d05-6c8c-4a08-9cea-92539c11e7e9.filesusr.com/ugd/3a9418_7aa08ef009c542e48e4d68c5958e86bb.pdf)
- KH 418 Control Interface Manual (https://a9843d05-6c8c-4a08-9cea-92539c11e7e9.filesusr.com/ugd/3a9418_1b2e140c52df4b2cbb9c5b7fdcc93439.pdf)
- KH 418 Control Video Tutorial (https://www.youtube.com/watch?v=j8ebBTuwL5w)
Oven is equipped with Set-Pro temperature controls.
- Before loading (or unloading) the oven, throw the power switch to the OFF position.
- Preferably load the oven cold so that the placement of materials to be heat treated is much easier.
- Blades / material to be heat treated should be placed in a fixture to hold the material vertically. Vertical placement is necessary to bathe the parts in heat which helps to prevent warping.
- When placing the blade fixture into the oven center it from left to right.
- When placing any material into the oven avoid contact with the heating elements and thermocouples.
- Once the parts are properly loaded and positioned, close the oven door and latch it.
- Throw the power switch to the ON position and perform the heat-treating operation.
- Do not enter the oven chamber while the heat-treating program is in process.
- Enter the oven chamber at the very end of the process which means the chamber can be very hot (up to 2400°F).
- Before entering the oven throw the power switch to the OFF position.
- Operate the latching action of the door handle and slowly open the oven door.
- Approach the oven slowly, high heat escapes quickly.
- Use tongs to remove the parts for quenching.
- Throw the oven power switch to the OFF position when the oven is not in use.
- Keep the oven door latched closed when oven is not in use.
- The rate (°F/hour) of heating can be As-Fast-As-Possible.
- Slowing the rate of temperature increase for the tempering process will avoid overshooting the lower temperatures involved (500°F/hour is a good place to start).
- To achieve As-Fast-As-Possible with Set-Pro control, choose a rate of Full.
- 1 segment firing: Heat treat firings are up to temperature, hold for a period of time and then shut off.
- With Set-Pro controls determine how many SEGS you want to use. Typically 1 is needed.
- In the event that your heat-treating program requires more than 1 segment. Refer to the data in the following tables.
- Tables are set-up in the order in which you will program the controls: number of segments first, then rate, then temperature, then hold time.
- Before removing any of your work from the oven, throw the power switch to the off position.
- Heat-Treating generally involves both hardening and tempering.
- Harden first then Temper. These are two separate processes and require different temperatures and different hold times.
- The following tables are labeled as Hardening and Tempering.
- Hardening is typically a one-time firing process.
- Tempering is often a repeated process. It’s not always the case, see in the following tables that some steels require up to 3 tempering firings.
Quick Steps for Custom Mode Programming:
1. Throw the power switch on the oven control panel to the On position.
2. The Set-Pro begins its initialization process and the display will illuminate.
3. The Set-Pro will finish its initialization process and then display IdLE (Idle).
4. Press the Enter key one time to begin the programming process. The display will read either, GLAS, ALAr, M-C, CEr or CUSt.
5. Use the Up or Down arrow keys to make the display read CUSt (Custom Mode) if it does not already.
6. Press the Enter key. USr is displayed along with some number.
7. Use the Up arrow key to choose. Choose which of the 4User program numbers will be used to store your program. Choices are 1 thru 4.
8. Press the Enter key. SEG is displayed along with some number.
9. Use the Up or Down arrow keys to choose. Choose the total number of segments used in the program. Your choices are 1 thru 8. Typically heat-treat programs usually use only 1 segment.
10. Press the Enter key. rA 1 is displayed along with some number.
11. Use the Up and Down arrow keys to choose. Program the temperature rate (°/hr.) for this segment. Heat-treat programs usually go As-Fast-As-Possible up to temperature.
12. Press the Enter key. °F 1 is displayed along with some number.
13. Use the Up and Down arrow keys to choose. Program the temperature set point for this segment.
14. Press the Enter key. HLd 1 is displayed along with some number.
15. Use the Up and Down arrow keys to choose. Program the hold time for this segment.
16. Press the Enter key. rA 2 is displayed. Repeat steps 11 thru 14 for all remaining segments.
17. Once all remaining segments have been programmed the display will read rEdI (Ready).
18. Press the Enter key to begin the heat-treating process.
The Set-Pro is now running your Custom heat-treat program. When the process is complete the display alternates between CPLt and total process time. Press the Start/Stop key at this point will cause the display to briefly read StOP and then IdLE.
Start/Stop Enter - the Start/Stop key starts and stops the heat treat process. It is also used to enter or store heat-treat program information during the programming process.
UP Arrow – VIEW SEG – SKIP SEG are used to select values when programming and allows for Viewing the current running segment as well as performing the Skip Ahead feature.
Down Arrow – REVIEW used to select values when programming and allows for the Review program feature.
Listed below are some of the more probable oven problems encounter along with the most common cause and repair advice.
- Check to see that the oven is plugged in.
- Check the circuit protection (breakers or fuses) to see that they are not tripped or open.
Oven Will Not Reach Temperature:
- Low voltage will slow heat up of the oven and, if the drop is low enough, it may cause failure to reach temperature.
- A failed element reduces the heat produced. Failed elements tend to be very visual and are easily seen. With the oven off (not running and unplugged) look at the elements for any breaks. If no breaks in the heating element then suspect a relay problem.
- A failed relay (fails to close) reduces the heat produced. While a relay failure acts like an element failure, a relay is not visible. If the heating elements appear to be intact replace the relay.
Oven will not stop firing (will noy shut off):
- Most likely a failed relay (failed closed). A failed relay may cause the oven temperature to increase when it should be decreasing. Identifying the failed relay is fairly simple as the element connected to it will remain on.
- Unplug the oven and remove the oven control panel. Follow the element leads to the relay to identify it.
- Relays are maintenance items, replace all of them when needing to replace one.
- Check the program. If tC/Fail is Displayed the thermocouple (temperature sensor) circuit is faulty. The thermocouple circuit is broken at some point, usually the thermocouple itself. The thermocouple circuit consists of the thermocouple, any connecting blocks and the thermocouple lead wire connecting to the Set-Pro.
Circuit Protection Opens (“Blown” Breaker or Fuse):
- Circuit protection can open for various reasons such as a short circuit and overheating.
- Short circuits occur when line voltage finds its way to another line or ground. They are usually violent occurrences with lots of noise, flashes of light and maybe a bit of smoke! During a short circuit the amperage goes very high. This increase in amperage exceeds the breaker/fuse rating which causes them to open (“blow”). Short circuits generally happen immediately upon plugging the oven in or running the firing. They generally do NOT happen after the oven has been on for some time.
- Overheating of the breakers/fuses can cause them to open (“blow”). Overheating needs time to happen. If the oven is running fine for a while and then the breakers or the fuses open most likely the problem is overheating and not a short circuit. Overheating reduces the amount of amperage a breaker/fuse will allow to pass before it opens. Overheating is caused by many factors, the most common are: loose wire connections at the breakers/fuses, the size of the wire “feeding” the oven is too small, the electrical receptacle is faulty or breaker/fuse is faulty.
Reasons for a Failed Heating Element:
- Heat-Treat oven elements rarely fail on their own. When they do fail its usually from contamination. If an element failure, double check the groove at the point of failure. Remove any debris from the groove with a sharp tool. Not doing so may allow the debris to destroy the replacement element.
Reasons for a Failed Relay:
- Relays are the switches that turn the heating elements on and off. They are moving parts and working all the time. Long, slow heat-treat processes make the relays work more which shortens their overall lifespan. Relay replacement is expected at some point.
END OF THE PROCEDURE