101 Heat Treat Tips

Want a free tip? Check out this read of some of the top 101 Heat Treat Tips that heat treating professionals submitted over the last three years. These handy technical words of wisdom will keep your furnaces in optimum operation and keep you in compliance. If you want more, search for “101 heat treat tips” on the website! This grab bag of 10 tips focuses on how to keep your heat treating costs down, either by maintenance strategies or product and process decisions.

By the way, Heat Treat Today introduced Heat Treat Resources this year; this is a feature you can use when you’re at the plant or on the road. Check out the digital edition of the September Tradeshow magazine to check it out yourself!

Oxygen Analysis as a Cost Saver

Investing in and using an oxygen analyzer on a regular basis can provide significant fuel cost savings and, at the same time, optimize uniformity and maximize capacity.

(Super Systems, Inc.)

New Diffusion Pump Technology Increases Production Output

Gain immediate positive net cash flow with a lease to own finance option by upgrading your diffusion pumps with the new immersion heater technology. The new style heater will extend oil life and reduce energy consumption. New heater technology can increase production by eliminating the need of dropping your pump every time you change oil for faster maintenance turn around. Drop in place pump design with improved performance.

(Leybold Vacuum USA)

TZM Moly Alloy for Structural Vacuum Furnace Components

For over 30 years, there has been a molybdenum alloy called TZM (Moly-0.5%Ti-0.1%Zr) which is far superior to pure molybdenum in vacuum furnace structural applications. TZM is slightly more expensive than pure moly, so OEM furnace companies use pure moly to keep their costs down for competitive reasons. But they could be offering it as an option for their buyers. Pure molybdenum metal undergoes recrystallization at temperatures as low as 2000°F. The recrystallized structure is very brittle at the grain boundaries, resulting in a structural component that also is very brittle. If you have a vacuum furnace with moly components, you have undoubtedly seen this with older parts. TZM alloy, however, does not recrystallize until around 2500°F, and even then it does not exhibit the brittle behavior of pure moly, because the recrystallized grain size is still very fine. TZM is also stronger than pure moly, as much as 3 to 4 times the strength at temperatures above 2000°F. For a 10-15% premium in cost, you can dramatically extend the life of your moly structural components in your furnaces.

(Grammer Vacuum Technologies)

How Much Lost Money Flows Through the Walls of Your Furnace

In a strict sense, heat flows through the insulating lining of your furnace wall: the lower the outside temperature in the furnace shell, the less heat is lost and, consequently, less money.

For example, an outside temperature on the oven shell of 160°F (71°C) equals a heat loss of approximately 190 BTU/hr ft2, just multiply this number by the square footage of the entire outside surface of the oven. A well-designed and well-maintained insulation can reduce the outside temperature of the shell, say 120°F (49°C), and heat losses would be close to 100 BTU/hr ft2, that’s 90% more heat lost and therefore fuel.

So, my Tip for today is: “Let’s go for the basics that don’t change, and it will always give good results.” By the way, how many furnaces are there in your plant and how many square feet do their surfaces add up to?

(Carrasco Hornos)

Never Go Cheap on These Two Things

There are 2 things in life you should never go cheap on: Toilet paper and combustion equipment! When upgrading or looking at new systems, spend the money to do it right. Designing on the cheap will only lead to operational and maintenance headaches. And trying to reuse the ancient artifacts when upgrading just to save a buck will cost you 10x that down the road. You don’t have to break your budget to do a quality job!

(Bloom Engineering Co., Inc.)

Don’t Be Cheap. Buy an IR Camera.

IR cameras have come way down in price—for a thousand dollars, you can have x-ray vision and see furnace insulation problems before they cause major problems—also a great diagnostic tool for motors, circuit breakers, etc. (And you can spot deer in the dark!)

(Combustion Innovations)

4 Reasons Not to Overlook Combustion System Maintenance

Anyone who has operated a direct fired furnace, especially one that relies on pressure balance ratio regulators for ratio control, knows that regular tuning is needed to keep the process running with the proper air to fuel ratio.

Here are 4 reasons not to skip regular combustion system tuning:

1. It can cost you money: Operating with more air than needed will reduce your furnaces efficiency and require you to burn more fuel. Conversely, operating air deficient, unless necessary for the process, results in unburned fuel being released with the exhaust gasses. In most cases the unburned fuel going up your stack is energy that you paid for.
2. It can decrease product quality and yield:  For many ferrous metals too much excess air will result in excess scale formation at high processing temperatures. On the contrary other materials such as titanium need to be processed with excess air to prevent Hydrogen pickup.
3.  It can reduce your furnace’s reliability:  The burners on your direct fired furnace will have a defined range of acceptable air to fuel ratios for proper operation. If your system wanders outside of this range, which can be fairly tight with today’s ultra-low NOx burners, you could start to see flame failures that result in unplanned shutdowns.
4. It can be a safety hazard: Apart from the possibility of causing burner instability, running with too little air will increase CO emissions. Unless your furnace is designed to safety exhaust CO you could end up exposing personnel working near your furnace to this deadly gas.

(Bloom Engineering Co., Inc.)

Inspection Mistakes That Cost

Rockwell hardness testing requires adherence to strict procedures for accurate results. Try this exercise to prove the importance of proper test procedures.

• A certified Rc 54.3 +/- 1 test block was tested three times and the average of the readings was Rc 54 utilizing a flat anvil.  Water was put on the anvil under the test block and the next three readings averaged Rc 52.1.
• Why is it so important that samples are clean, dry, and properly prepared?
• If your process test samples are actually one point above the high spec limit but you are reading two points lower, you will ship hard parts that your customer can reject.
• If your process test samples are one point above the low spec limit but you are reading two points lower, you may reprocess parts that are actually within specification.
• It is imperative that your personnel are trained in proper sample preparation and hardness testing procedures to maximize your quality results and minimize reprocessing.

(Young Metallurgical Consulting)

Question the Spec! Save Money!

Before you specify a heat treatment, stop and consider your options. Rather than reusing an old specification, ask the design engineer to determine the stress profile, and base the hardness or case depth on real stress data. Is this complicated? Maybe. But especially for carburizing, why pay for more depth than you need, and why take the risk of inadequate strength? The 21st century is here. We have ways to help with the math. Let’s move beyond guess and test engineering methodology.

(Debbie Aliya)

The Right Furnace Atmospheres Will Pay Dividends

Save money on your furnace atmospheres by employing the driest and leanest furnace atmosphere blends possible. Furnace atmospheres are a compromise between keeping it simple and supplying exactly the atmosphere to meet the unique requirements of each material processed. Organizations have different priorities when it comes to atmospheres—heat treat specialists may want to be able to run as many different materials as possible using a limited array of atmosphere types, while captive heat treating operations often want exactly the atmosphere approach to maximize the benefits for their specific processes/products.

The dewpoint (water content) of the atmosphere in the furnace is a key factor in its performance. At high temperatures, water in the atmosphere can break down, releasing oxygen that can cause oxidation. You must maintain a high degree of reducing potential to achieve the surface finish and processing results desired. If the furnace atmosphere gas is wet, you’ll need a gas blend richer with hydrogen than you would if your atmosphere blend had a lower dewpoint (less water vapor content). Since hydrogen costs 10 times more than nitrogen, it is more economical to run a leaner atmosphere than a richer atmosphere. By running the driest atmosphere blend possible, you may find that you can lean down your atmosphere (consistent with the metallurgical needs of your product/process) by reducing the proportion of hydrogen and increasing the nitrogen. In doing so, you may recognize meaningful savings.

Check your furnace atmosphere raw materials and process and obtain the driest atmosphere possible. Control your atmosphere dewpoint by adding humidity as needed to the driest starting blend possible rather than accepting a wet atmosphere and trying to process your parts. You’ll achieve the best compromise of excellent results at the lowest cost.

(Nel Hydrogen)

Check out these magazines to see where these tips were first featured: