Powder Metallurgy Tests for Dies & Fabrication Equipment
- Dies and fabrication equipment are made of steel or metals that are ferro-magnetic, which is required for a powder metallurgy test. During the course of operation, the dies and fabrication equipment can crack under the stress of the pressure being employed to produce parts. A cracked die produces parts not within the required specifications. Part of the preventive maintenance program includes periodic powder metallurgy testing, to determine if the die or fabrication equipment is damaged in any way.
- The magnetic particle inspection employs a powder or magnetic dust that identifies the problem areas of a die or piece of fabrication equipment. The devices must be cleaned thoroughly before conducting this type of metallurgy inspection. The powder is spread over the top of the die, and magnetic force is applied to the ferro-magnetic material. Once the force is applied, any cracks become magnetized, causing crack to attract the powder.
- The powder used to conduct a powder metallurgy test on dies and fabrication equipment is specifically designs to work for this type of NDT inspection. The powders come in many different colors, so easy identification of the crack can be accomplished. Many NDT inspectors employing this powder carry multiple colors with them so they can use a color that contrasts well with the color of the die or fabrication equipment. For example; do not use a light color powder to conduct a metallurgy test on light-colored dies. Use a bright color, such as red or orange, so you can locate the crack and mark the problem area.
- Different types of yokes are available for conducting powder metallurgy test. Some yokes are stationary and not large enough to conduct a powder test on dies. Most inspectors use a handheld yoke that can be transported to the location of the die or fabrication equipment. The yoke is an inspection device that produces the current of magnetic force, which magnetizes the crack. The problem with these handheld yokes is the limited area that can be inspected at one time. You must perform the powder metallurgy test on different sections of the die, then move onto another section to complete a magnetic particle inspection on the entire die surface.