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All About Tool Wrap

Tool Wrap

What is Tool Wrap?

The Tool Wrap is a stainless steel .002 thick foil. You can use it to protect the surface of your tools and dies during hardening. It also keeps your tools from decarburization (scaling).

Do you have the Tool Wrap  in different materials?

Yes, we do. Our regular Tool Wrap material is Type 321 Stainless Steel, which will work great in temperatures up to 2000 degrees F. You can also opt for the Type 309 Stainless Steel High-Temp material which is a great fit for  when you are in temperatures up to 2240 degrees F.

Who can use this Tool Wrap and where?

You can use the Tool Wrap for various purposes, in manufacturing and related processes. The professionals who use our Tool Wrap include maintenance staff, mold makers, machine operators and people who work in manufacturing companies.

Do you have different thicknesses available for the Toll Wrap?  

Yes, we do. We have two other thicknesses are available in 309 and 321 Stainless Steel, which you can specially order, as there is a minimum requirement per special order. To get a quote tailored to your needs, please call our customer support unit at (enter number).

How can I use Tool Wrap ?

The Wrap is usually utilized when there is no controlled vacuum furnace available, during a heat treating process. You can use it to save time by getting the hardening process done instead of sending the parts out for heat treatment. You do this by placing the part or tool that needs heat treatment in an envelope you form by folding into two halves, a sheet of the Tool Wrap. After that, you then seal the open ends of the envelope to keep out the air and give you the results you’ll get if you use a vacuum furnace. ,

Is it necessary for  the Tool Wrap package to be air tight throughout the heating  process?

Typically, the surface of your tool will be susceptible to pitting and scaling, if the envelope is not air-tight. This is because of the excess oxygen that will go into the envelope. On the other hand, if the part is oddly-shaped, you may need a vent for air. It is also crucial to know that no difference exists between the uniformity of hardness between wrapped pieces, whether they are tied loosely or tightly.

When is it important to allow venting in the Tool Wrap envelope?

 Because of entrapped air, the Tool Wrap envelope will expand and contract during the heat treatment. If the part or tool that needs heat treatment is large r oddly-shaped, there may be a large amount of air that strains the foil enough to for the tool or part to cut through the wrap.  Although, this is not a serious problem, it can be taken care of by one simple vent. You can create a vent by making your Tool Wrap envelope the normal way and leaving one corner to  open about a quarter inch. Then, load the envelope into the hot furnace and make sure the vent remains open. The trapped air will escape through the vent as the envelope heats, and get rid of strains from pressure built up from the heating process. When the envelope becomes hot, cover  the vent  using a pair of tongs. Then, leave the envelope in the furnace till the end of the heating cycle. This venting technique also reduces any strain that results from the  collapse of an expanded package.

How much of the Tool Wrap do I need?

You should cut a piece of Tool Wrap from the roll large enough to completely cover the tool or part twice (from top and bottom), and allow for overlapping by at least 3 inches all round.

How do I cut the Tool Wrap?

You can easily cut the Tool Wrap material either with snips or heavy scissors.

How do I seal the edges of the Wrap?

After you create an open edge of the envelope by covering your part or tool on the top and bottom with the Tool Wrap, fold them over at least twice.  Make sure you expel all the excess air  you seal without damaging the Tool Wrap. You can also use a seam roller tool to make sure the seam is  air-tight -.

Is a special tool important to seal the edges of the Tool Wrap?

No, it is not. However, you can get the job done faster if you use a seam roller to flatten and cover the edges. it is quicker and easier if you use a seam roller to flatten and seal the folded edges. These rollers also help to ensure an airtight seam.

What is the right procedure  to create a Tool Wrap envelope?

To create a Tool Wrap envelope, cut a piece of Tool Wrap, large enough to cover the complete tool or part twice (top and bottom) and allow some  overlapping by at least 3 inches all around the part. The Tool Wrap material can be cut with snips or heavy scissors. Make sure you expel all the excess air  you seal without damaging the Tool Wrap. You can also use a seam roller tool to make sure the seam is  air-tight -.

At what temperature are the wrapped pieces treated?

Typically,, the oven is preheated to a specific temperature. After the tool has reached this temperature, it is then held at a high heat (also called soak time) of a higher temperature for a time according to your machinist’s manual. Quenching then follows either in oil, water or in air at room temperature.

What temperature does the Type 321 Stainless Tool Wrap work at?

The average operating temperature for our Type 321 Stainless Tool Wrap is 1850 degrees F, but it can work in varying temperatures up to 2000 degrees F. In all, the operating temperature for Tool Wrap is quite difficult to state because these temperatures are determined by the length of time in the furnace. At 1850 degrees F, the Tool Wrap can be in a furnace without degrading for more than four hours. At 2000 degrees F, the Tool Wrap can perform well up to four hours. Of course, these are just rough guesses and you need to ensure  your furnaces are calibrated correctly. Other elements which can affect the operating temperatures and the Tool Wrap performance are contaminants within the envelope and improper sealing. There is no straightforward answer to what temperature Tool Wrap works at, because the heating times need to be first known.

Can the Tool Wrap be used to harden tool steels other than air-hardening?

Sure, but oil & water hardening tool steels may fail to develop a full and uniform hardness. High-speed tool steels, notwithstanding the attainment of uniform hardness, create problems because the foil may fuse to the piece at high temperature, resulting in an air leak and causing decarburization.

What is decarburization?

Decarburization is the direct opposite of carburization. It happens when there is a  loss of carbon from the surface of a tool steel as a result of heating at a high temperature in an atmosphere that reacts with carbon.

Is decarburization undesirable?

Yes. If surface carbon drastically reduces, the outer surface will not get the desired Rockwell and the steel will be left with a soft skin. Tool steel fatigue typically happens in the decarburizated layer.

After heat treatment, should the part be removed from the Tool Wrap before  quenching?

Not typically. , This is because removing the foil before quenching is not only difficult, but may also result in surface scaling and decarburization from exposure to the air. However, the insulating effect of the Tool Wrap may sometimes make it important to remove it before quenching in order to get faster hardening.

Is any surface preparation  required after the heat treatment?

Yes and no. The reason is because a blue or tan surface color will be evident, due to oxidation by entrapped air. This discoloration is not harmful at all and you can get rid of it by bluffing, if you want.  However, this light oxide film can boost performance in many tooling operations because it prevents metal pick-up and helps to hold the die lubricant.

Can I reuse Tool Wrap envelope?

No, we do not recommend this for various reasons. What makes the Type 321 or 309 Stainless Steel a great fit for decarburization prevention is its titanium content. It serves as a catalyst and  reacts with any oxygen under the foil before the oxygen can react with the surface carbon in the tool. After use, the titanium is reduced , thereby offering no safety  for re-use. Also, the foil becomes very brittle after use, prevents the wrap from forming a tight seal and makes it more prone to tears.

When should a part be double wrapped in Tool Wrap?

Occasionally, it is important to double wrap the part to ensure that the tool is sufficiently protected. At a high temperature, the Tool Wrap becomes very soft and must be handled very carefully to avoid damage. Tools and parts with sharp edges may need  to be  double-wrapped to avoid air exposure from tears. However, increasing  the hardening/heating times can also compensate for the extra Tool Wrap. We recommend that that a small amount of experimental work be done before using this material for the first time. We also offer a Tool Wrap for higher temperature hardening, which may be a better alternative to double wrapping.

Why does the Tool Wrap stick to a tool, die or part after heat treating?

At very high temperatures, the Tool Wrap may be joined or be weld to the piece during hardening. This is generally caused by tight wrapping, uneven support of the work surface such as a heat treating basket or mesh, or any oil stain or residue left on the surface of the metal .On the other hand, , if the part is “clean”, loosely wrapped and smooth work support surfaces are used and this still results in sticking, a liberal dusting of aluminum oxide or magnesium oxide can solve this problem. We strongly recommend that that a small amount of experimental work be done before using this material for the first time. .

Can I bright-harden small tools or parts?

Yes, bright hardened parts can be gotten by using Tool Wrap. To get maximum brightness, the part or tool must be cleaned and free from any oil stains before it is subjected to heat treatment. The part must be firmly sealed in a Tool Wrap envelope with several extra edge folds to make sure no air can enter and that the parts does not pierce through the Tool Wrap. It is important that the envelope is transferred to the quenching medium from the furnace so you can get great results.  Sometimes, , parts should be removed from the Tool Wrap envelope before quenching. The Tool Wrap here serves as an insulator that  makes it necessary to remove the Tool Wrap before quenching in order to obtain more rapid hardening/tempering. This can be done by slitting the envelope and allowing the part to fall into the quench immediately.

Do I have to wear  leather/thermo gloves when using the Tool Wrap?

You need to exercise great caution when preparing your material for use. We recommend leather gloves are recommended so you can prevent accidents and reduce any risk of being hurt. We also recommend thermo gloves when you are working with heat.

Is extra hardening/heating time important to make up for for the Tool Wrap envelope?

You may add  two or three extra minutes to the hardening process to make up for the heating of the Tool Wrap. For-double wrapped parts, you may also need to add some extra time. You may also want to make up for the insulating effect of the Tool Wrap by raising the  temperature to 75 degrees. However, the right  amount can only be known doing some quick experiments on the kind of metal being worked on.