Stainless steel powder metrology

PROCEDURE The mixtures underwent a complete procedure to obtain the results and compare them according to different standards. The procedure of the experiment is explained in detail in this part of the report. Preparation of the Mixture The powder mixture, each specimen separately, is weighed and the weight recorded. The process is initiated after the weighing. The powder is properly mixed using tubes and revolving machine. In these experiments, two different mixtures, ferrous 316L with 1 gram silicon and the same mixture with the addition of 1gm boron is used. The mixtures were then sintered and quenched under different temperature conditions. The sintering has to be discussed briefly to be understood. Sintering and Quenching The specimens prepared are pressurized at 700 MPa and made into round discs as shown in the picture below. . The specimen is heated inside a closed container, to different temperature. As recorded before, there are in total 13 specimens which are used in the experiment. Each specimen is labeled properly before any kind of experiment us conducted on it. The two mixtures samples of A and B are heated at 1220, 1230, 1235, 1240, 1280, and 1295o C respectively. Each sample was then sectioned, mounted and polished for microscopical examination. These methods are explained in detail in the following part of the report. Sectioning It is essential for maximizing the working parameters since incorrect cutting can waste small samples, which are very difficult to make. The sample with deformation should be given maximum support to un-clamp them (German, 1990). Mounting The samples are too little in size to handle the different steps of the procedure. It is essential for maximizing the working parameters. Therefore a uniform and rounded surface is given to the specimen so that the damage is prevented during grinding and polishing procedures (German, 1990). Grinding The samples are grounded to reach finer surfaces. Grinding is done under stream of water to remove any free particles that are being cut out of the sample and to minimize the eroding effect on the sample and to save its surface from rash cuts. The specimen is then dried out as there was water on it (German, 1990). Polishing It is also a very important part of the experiment. Since for the photography the best surface is required. It is done by rotating a cloth over the surface with the help of a polishing machine. A polishing liquid is also used (German, 1990). Etching The samples need to be etched as the last part of the procedure. But before etching is done, the surface has to be cleaned and free of any impurity. The samples have to be etched with a proper liquid to prevent damage. During the process, the sample is removed from the sample when the first blooms of grains are observed. After etching, the samples are washed ruinously with washing material, either water or alcohol. Warm air is then passed over it. If the material is of soft nature, it must be covered so the surface can be saved (German, 1990). Microscopic examination This is a very important process since the examination with naked eye would not reveal the required results. Special method of illumination is used between the two controlling diaphragms to enlighten the eye piece where the results can be seen and photographed (German, 1990). Recording before the Procedure The two