Tool Wrap and Its Uses

Tool Wrap and Its Uses

Tool Wrap and its Uses

A tool wrap is a foil or sheet used for wrapping and protecting the surfaces of different tools, die parts and other metals during heat treatment or hardening process. A tool wrap is made of stainless steel and is used to protect the surface of a tool or die from carbon depletion, chromium carbide build-up, oxidation and scaling.

Traditionally, hardening is done by heat-treating the tool in a controlled environment, like a vacuum furnace, in order to increase the toughness, wear resistance and strength of the material. A vacuum furnace does not allow air to enter, and eliminates the risk of contamination, making the heat treatment process efficient. While having a vacuum furnace is great, it is hard to say the same about the investment costs that come with it.

A vacuum furnace is usually large in size and costs a lot of money to install, set up and operate. Unless a running project can generate enough revenue to cover the expenses incurred by a vacuum furnace, the costs may not justify setting one up.

When a vacuum furnace is not available, the tool or die can be heat-treated by wrapping and carefully sealing the part in a stainless steel tool wrap which provides similar atmospheric conditions by confining the air inside the sealed envelope. The objective is to keep as much air out as possible.

The too wrap must be carefully sealed at the edges to keep it airtight because if oxygen can enter through any opening or hole it can lead to decarburization or formation of pits and scales on the tool surface.

At the edges, the tool wrap must be sealed thoroughly by folding them at least twice. Sealing can be done either manually or by using a seam roller which eliminates crease around the edges. This creates a secure envelope and expels the excess air uniformly.

Once the tool is wrapped, it is ready to be sent for heat treatment inside an industrial oven.