Thirteen new manufacturing jobs will open up with the $23.5 million expansion of an Alabama heat containment refractory production facility. The Ohio-based company supplies products used in a variety of industrial applications, including heat treating operations.
Paul Jamieson President & CEO Allied Mineral Products
Allied Mineral Products, an Ohio-based producer of monolithic refractory ceramics, recently broke ground on the major expansion at its Pell City, Alabama, location. The growth project will add a 200,000-square-foot production facility on the company’s current site and expand the workforce with thirteen new manufacturing jobs added to the company’s current workforce of 81 full-time employees. The project is expected to be completed in late 2025, increasing the facility’s production capacity and improve efficiency. State and local officials joined executives and employees of Allied Mineral Products, LLC (Allied) at the groundbreaking ceremonies marking the investment.
“Our partnership with Alabama is strengthened yet again with the expansion of this plant which we originally built in 2019,” said Paul Jamieson, president and CEO of Allied Mineral Products. “Locating our facility in Alabama was part of a long-term strategy to expand our manufacturing presence in the south to be closer to our customers. Because of the quality of this workforce and the local support here, our growth in Alabama has been faster than we planned. We are excited to be expanding our facility so soon and are confident this will help us to continue that growth.”
The press release is available in its original form here.
During the day-to-day operation of heat treat departments, many habits are formed and procedures followed that sometimes are done simply because that’s the way they’ve always been done. One of the great benefits of having a community of heat treaters is to challenge those habits and look at new ways of doing things. Heat TreatToday‘s 101 Heat TreatTips, tips and tricks that come from some of the industry’s foremost experts, were initially published in the FNA 2018 Special Print Edition, as a way to make the benefits of that community available to as many people as possible. This special edition is available in a digital format here.
Today, we begin an intermittent series of Technical Tuesday posts of the 101 tips by category, starting with Atmosphere Control.
Atmosphere Control
Heat TreatTip 5
Out of Control Carburizing? Try This 11-Step Test
When your carburizing atmosphere cannot be controlled, perform this test:
Empty the furnace of all work.
Heat to 1700°F (926°C).
Allow endo gas to continue.
Disable the CP setpoint control loop.
Set generator DP to +35°F (1.7°C).
Run a shim test.
The CP should settle out near 0.4% CP.
If CP settles out substantially lower and the CO2 and DP higher, there’s an oxidation leak, either air, water or CO2 from a leaking radiant tube.
If the leak is small the CP loop will compensate, resulting in more enriching gas usage than normal.
Sometimes but not always a leaking radiant tube can be found by isolating each tube.
To try and find a leaking radiant tube, not only the gas must be shut off but combustion air as well.
So you just ran a batch and the parts are bad. Now what? According to Jim Oakes at Super Systems Inc., here is a good checklist to use to start isolating the problem. While not exhaustive, this list can at least take you through a progression of steps to help start identifying the culprit.
Step 1: Review the process data for abnormalities. Did the setpoint for temperature and atmosphere get set properly? Does the process chart show good control of the temperature and atmosphere? Was the time at heat correct? Was the quench and temper processes run properly?
Step 2: Check the generator to make sure it was pumping out the right atmosphere.
Step 3: Check the furnace atmosphere. Even if the generator is working, there may be leaks in the furnace.
Step 4: Check carbon controller to make sure it matches furnace atmosphere reading. Verify probe accuracy and adjust carbon controller.
Step 5: Do probe troubleshooting. And if all else fails . . .
Step 6: Replace the probe or call Super Systems for help.
Many factors can contribute to why parts are not meeting the correct hardness readings. According to Super Systems Inc., here is a quick checklist of how to start narrowing down the culprit:
Review process data for abnormalities: The first thing to do is make sure the parts were exposed to the right recipe. Check the recorders to make sure the temperature profile and atmosphere composition were correct. Make sure all fans and baffles were working correctly. Determine if any zones were out of scope and that quench times were acceptable. If any red flags appear, hunt down the culprit to see if it may have contributed to soft parts.
Check the generator. Next, check the generator to make sure it is producing the gas composition desired for the process. If available, check the recorders to make sure the gas composition was on target. If not, check the generator inputs and then the internal workings of the generator.
Check the furnace atmosphere. If the generator appears to be working correctly, the next step would be to check the furnace itself for atmosphere leaks. Depending on what type of furnace you have, common leak points will vary; for continuous furnaces, common leak points are a door, fan, T/C, or atmosphere inlet seals. Other sources of atmosphere contamination may be leaking water cooling lines in water-cooled jackets or water-cooled bearings. More than likely, if the generator is providing the correct atmosphere but parts are still soft, there is a leak into the furnace. This will often be accompanied by discolored parts.
Check carbon controller to make sure it matches furnace atmosphere reading (verify probe accuracy and adjust carbon controller). This can be done using a number of different methods: dew point, shim stock, carbon bar, 3 gas analysis, coil (resistance), etc. Each of these methods provides a verification of the furnace atmosphere which can be compared to the reading on the carbon controller. If the atmosphere on the carbon controller is higher than the reading on the alternate atmosphere check, that would indicate the amount of carbon available to the parts is not as perceived. The COF/PF on the carbon controller should be modified to adjust the carbon controller reading to the appropriate carbon atmosphere. If the reading is way off, it may require the probe to be replaced.
Configuring your atmosphere controller to ensure the correct carbon potential readings can sometimes be tricky. We suggest you double check your atmosphere control settings to make sure they are set up correctly. Before making a change to the carbon controller, make sure the atmosphere that the carbon probe and carbon controller are reading is matching up to an alternate method of atmosphere. This can be done using a number of different methods: dew point, shim stock, carbon bar, 3 gas analysis, coil (resistance), etc. Each of these methods provides a verification of the furnace atmosphere which can be compared to the reading on the carbon controller. The COF/PF on the carbon controller should be modified to adjust the carbon controller reading to the appropriate carbon atmosphere.
It is important to make sure that the alternate method of verifying atmosphere is done properly (sampling ports, time for atmosphere exposure, sample prep, etc).
The calculation of carbon in the atmosphere using a carbon/oxygen probe is based on the output millivolts — created based on the partial pressure of oxygen in the reference air versus partial pressure of oxygen in the furnace, the temperature of the furnace, and a calculation factor referred to as COF (CO Factor), PF (Process Factor), or Gas Factor.
The carbon controller can be modified so the COF/PF value can be changed to match up with the alternate reading. A furnace calculator on the SSI website or mobile app can help determine what these settings should be. It is important to note that you should not change these values to the point where you are masking another issue such as a bad probe or a furnace/generator issue.
Again, if the reading is way off (a setting of a COF below 130, for example), it may require the probe to be replaced.
If you’re having atmosphere problems with a furnace that has been operating normally for some time, avoid the temptation to remove the carbon probe. There are several tests you can run on nearly all carbon probes while the probe is still in the furnace, at temperature, in a reducing atmosphere. Super Systems Inc. provides an 11-step diagnostic procedure in a white paper on their website, in a paper titled, “Carbon Sensor Troubleshooting” by Stephen Thompson.
Atmosphere furnace pressure should be only slightly above ambient. The range should be between 0.25 – 0.35 inches water column. Higher pressures in multiple zone pusher furnaces will cause carbon control issues. High pressures in batch furnaces will cause high swings when doors and elevators move.
Wisdom dictates a trust-but-verify approach to your endothermic generator. Although your generator is supposed to crank out a consistent endo atmosphere, we suggest periodically verifying the integrity of that atmosphere with a dewpoint analyzer or a 3-gas analyzer. Generator control systems provide control of air gas ratio and possibly a trim system, used to maintain a dew point that could be rich (too much gas) or lean (too much air). The dew point range could typically be between 30°F and 50°F. Flowmeters are provided to maintain a base ratio (2.7 : 1) for the air/gas mixture supplied to a retort filled with nickel-coated catalyst. The gas is then passed through an air cooler (some older systems used water) to freeze the reaction so the gas can be transported through a header system to furnaces. The ratio at which the gas is generated offers a dew point that can be measured. The makeup of the endothermic gas provided by a generator is typically 40% hydrogen, 40% nitrogen, and 20% carbon monoxide. Maintaining these percentages will result in a carburizing atmosphere that is conducive to best carburizing practices.
Non-dispersive infrared analyzer (NDIR) systems are invaluable when trying to troubleshoot generator issues. The analyzer will typically measure CO, CO2, and CH4. As mentioned earlier, if we know that 20% CO is being generated, we can cross check the air/gas ratio and sticking flow meters, or determine that an adjustment of the air and/or gas ratio is required. The measurement for indication of sooted or nickel depleted catalyst can also be achieved by using an analyzer. If the indicated measurement of CH4 is higher than .5%, a burnout of the catalyst is required, using the manufacturer’s required procedures. If after a burnout the CH4 level is still high, the catalyst may need to be replaced altogether.
If you have any questions, feel free to contact the expert who submitted the Tip or contact Heat TreatToday directly. If you have a heat treat tip that you’d like to share, please send to the editor, and we’ll put it in the queue for our next Heat TreatTips issue.
“Lightweight, high-performance metals leader Alcoa (NYSE:AA) today launched a family of innovative foundry alloys designed to meet the growing need for both part performance and lightweighting in the automotive industry and beyond.”
Looking for a solid primer on heat treatment that you can share with your new heat treat employees, family members, open houses, or at a college job fairs? Take a look at this excellent resource from South Carolina Electric & Gas (SCE&G).
Key Points
Heat treating is a widely used industrial process to optimize the mechanical properties of metal.
Metal is heated to a set temperature and then cooled according to a prescribed schedule.
Heat treating processes vary according to equipment type, energy source, temperature profile and environment.
