ROLLER 2920454 - Caterpillar

Surface Hardness
Illustration 51 g02764619
Krautkramer Branson MIC 10 Hardness Tester
The surface hardness of chrome to be stripped can easily be checked with a portable hardness tester. The Krautkramer Branson MIC 10 is a unit for fast, accurate, hardness measurements. The unit works by measuring the linear displacement of a pointed probe, which is forced against the test piece.Masking Aids
Masking aids are used to protect certain areas (threads, bolt holes, etc.) on the substrate from the HVOF and/or surface preparation processes. The protected areas usually require no salvaging or repair.Masking aids can be divided into four categories:
Tapes
Masking compounds (putty)
Paint
Permanent masksNote: At the end of this bulletin, several masking aid suppliers will be listed.Tapes
Tapes can be used to protect the surface of components for both the HVOF and the surface preparation processes. Masking tapes are a consumable to the salvage process, because they can only be used one time.Masking a surface for surface preparation with tape can be accomplished in the following manner.Apply several layers of duct tape or masking tape to the area that requires protection from the grit blasting operation.Conventional tapes used as a masking aid for the surface preparation process, must be removed prior to the HVOF operation due to their flammable nature.Masking a surface from the HVOF process with tapes requires a special metal or thermally resistant tape. These tapes are more expensive than conventional tapes, but are easily used to protect areas that have an irregular contour or shape.Masking Compounds
Masking compounds are a soft conformable putty-like material for masking holes, grooves, key slots, or other unique characteristics. The material is easy to use.The putty-like material is pressed onto the substrate by hand. After applying the material to a surface for protection, the masking compound must be cured. The amount of heat and required curing time varies depending on the material being used. Average curing cycles are 25 minutes at 121° C (250° F).Once the material has been cured, it becomes a strong abrasion resistant and thermally resistant material. Following the HVOF process, the material can be cut and removed like a silicone material.Masking compounds are available in tapes, extruded profiles, and other pre-formed shapes. However, these masking compounds can only be used once.Paint
Masking paints are applied by brush to a surface for protection. The paint creates a surface barrier that a thermal sprayed coating cannot bond to (similar to a surface that has not been properly prepared). Following the coating operation, the thermal sprayed material can be removed from the painted area.For thermal spray processes (that is, flame spray and arc spray), paint is a viable masking compound. Paints are not able to withstand the higher temperatures of the HVOF process. As new paints are developed, this section will be updated.Permanent Masks
Permanent masks are objects or materials that can be used multiple times. These items can be any of the following or a combination of the following:
Shields placed between the gun and substrate
Sleeves or collars
Rubber stoppers (some stoppers will be considered consumables)
Thermal blanket/insulation materials
Cutouts (steel or rubber)Suppliers
Tape
3M