How To Use A Metallographic Microscope
ABSTRACT: Metallographic microscopes are special microscopes used for studying the structure of metals and its alloys. The proper way of using metallographic microscope is explained in the article below.
Whenever there is a need to study or identify a certain metal or alloy, metallographic microscopes are used. Metallographic microscopes can also determine whether a particular alloy is processed correctly. It is also the device that is employed if multiple phases need to be examined in a certain material, define its imperfections and impurities, as well as determine the damages it had sustained. These are also the concepts that metallographic microscopy is primarily concerned about.
When using metallographic microscopes, these are the things that you need to do:
1. Prepare the table from which the microscope is going to be used on. Make sure that there are no debris or any objects placed in the table. Even a small object like the cap of a pen can cause the microscope to topple over unexpectedly. Make sure that the table is all clear. Lay the microscope on a flat surface and near the power outlet, if possible. Doing so would secure all the cables, thus reducing the possibility of accidents.
2. Calibrate the microscope as per instructions. Generally, you should calibrate microscopes using the low power objectives first. Use an equally low power eye piece. Whenever possible, use a total magnification power of 100x or lower. This would ensure that you are to achieve the right focus and image sharpness of the specimen that you are viewing. If the manual of your metallographic microscope has specific instructions, follow what is written in there accordingly.
3. Prepare your specimens as necessary. The samples that are to be used for metallographic microscopy needs to be especially prepared before putting them on the microscope’s stage. More often than not, they have to be set into a certain epoxy potting substance. Only after doing this step that you can use the metallographic microscope to view the sample with. Some samples are sturdy enough, though. For these sturdy samples, there’s no need to mount them with an epoxy potting. You can determine if a sample is strong enough if they can withstand intensive polishing and grinding.
4. Polish the specimen. After setting the specimen in an epoxy potting, it has to be polished to a certain level. Or it can be etched if so desired. Etching using electrochemical and chemical procedures are necessary when the grain structure of the material is the optimum interest of observation.
5. View the specimen as required. Viewing the specimen can be attained if it is placed properly below the objective lens of the microscope. Look through the eye piece and analyze the specimen as necessary. Using a metallographic microscope, you can start determining the metal’s grain size, structure, and growth. Its inter-metallic phase microstructures can also be detected. The sample’s porosity, shrinkage, inclusions, and interfaces can be examined as well.
6. Adjust the lighting system if needed. Most metallographic microscopes are equipped with a built-in illumination system that can be adjusted to go brighter or dimmer by a merely turning the knobs. The aperture diaphragm may also be adjusted as follows so as to achieve the best possible image and resolution of the specimen metal being viewed.
7. Connect the microscope to an external imaging device. A monitor or a personal computer should do the job. If there is a need for additional image output other than the one seen through the metallographic microscope’s eye pieces, then those devices should be properly installed. Most metallographic microscope are trinocular microscopes. This means there is an additional port for which an imaging device such as a digital still camera or a video camera can be connected. These should be installed accordingly as per instructions on the digital camera’s manual or the metallographic microscope’s manual.
8. Save the metallographic images as necessary. If you are connecting an external imaging device to the microscope, then you can start saving the images that were produced using the necessary recording or storage devices. If the microscope is connected to a computer, you can simply save and store the pictures to your hard disk or to a compact disc.
These are the steps on how you can use metallographic microscopes. Metallographic microscope are feature-rich microscopes. They have complex characteristics and uses. And as such, they are used for special applications by professionals. But with these steps listed here, you can using these devices like an expert.