High Quality Heat Treating Made Simple with Sentry Disposable Heat Treating Containers
Sen/Pak®...The disposable metal-foil heat treating container method*, produces extremely high quality, close to vacuum results, in 3 simple steps.
* Pat. No. 3,470,035
Sen/ Pak containers also offer unique protective properties for other heat treating applications.
Facts about Sen/Pak® Heat Treating Containers
The Sen/Pak System of heat treating utilizes a metal foil container to provide a protective sheath and to automatically neutralize the entrapped atmosphere. The lightweight Sen/Pak container heats more rapidly than the work piece. As a result, the undesirable elements in the entrapped atmosphere react with the Sen/Pak container long before the work piece is hot enough to be damaged by them. In addition, the Sen/Pak container acts as a protective barrier throughout the hardening and quenching operation.
The Sen/Pak System is ideal for many tool steel hardening applications when an atmosphere furnace is not available. The range of applications includes hardening of small pieces of molybdenum high speed steels. There are limitations to the use of the containers at high speed hardening temperatures. In addition, many oil and water hardening steels are difficult to quench properly in the Sen/Pak container. For premium hardening of all types of tool steels, Sentry offers the Diamond Block System of atmospheric control.
INSTRUCTIONS FOR THE SEN-PAK HEAT TREATING METHOD
WARNING: Use Caution Handling Container, Edges are Very Sharp!
Select a Sen-Pak Container large enough to avoid damagind the walls during insertion of the pieces to be heat treated. A letter opener type tool can facilitate opening and loading of the container. Position the work peices as near to the colsed end as is practical. Exhaust excess air and realign the open end by manually flattening the assembly prior to sealing. Seal the container by folding the open end at least 3 times.
Load the container directly into hot furnace at hardening temperature. The container insulates the tool sufficiently to lessen thermal shock. Preheating will reduce the protective qualities of the process and is not normally required.
Heat the work at hardening temperature a fw minutes longer than normal to allow for heating of the container. Quench in the container whenever possible for cleanest results.
Properly treated smaller peices can have a bright finish. Larger peices may show some discoloration but this will not affect the quality of the hardened tool. Do not reuse containers as they no longer have the alloys necessary to neutralize entrapped atmosphere.
PROBLEM STEELS: Oil and Water hardening steels must be cut from the container using scissors or shears while hot before quenching or they will not be properly hardened. This is a difficult and hazardous procedure. Sentry recomments atmosphere furnaces for oil and water hardening steels. High speed steels can also be a problem. Larger pieces left in the furnace for times of 20 minutes or longer at temperatures above 2200 degrees can adhere to the container. The container can also oxidize and fail. Use of larger high speed steel applications. Other steels may present problems. Sen-Pak containers are less effective at temperatures below 1400 Degrees F as they loose their ability to neutralize the entrapped atmosphere. For special applications it is best to perform a sample heat treat of a spare part.