Standard for porosity detection of cemented carbide by metallographic microscope
1. The size of the pores on the grinding surface is defined as the size of the pores.
2. For pores less than or equal to 10um, observe the grinding surface of the sample under the magnification of 100 or 200 times and evaluate it.
3. For pores larger than 10μ m and smaller than 25μ m, observe and evaluate the worn surface of the sample with a magnification of 100 times under the metallographic microscope.
4. If the pores larger than 25um need to be inspected, they should be inspected under the appropriate magnification of less than or equal to 100 times under the metallographic microscope.
5. If the porosity or uncombined carbon is unevenly distributed on the grinding surface of the inspected metallographic specimen, its position, such as the top, top, edge (shell) and center, must be identified.
There are relatively many methods to detect the porosity of cuttings and cores. In logging, cuttings can be measured by drilling logging, microscopic examination of cuttings and nuclear magnetic resonance analysis. In logging, compensated neutron, compensated density and acoustic time difference logging are commonly used methods to measure porosity, and some universities and scientific research institutions have also developed special equipment to measure cuttings porosity. Logging while drilling, microscopic examination of cuttings, etc. have some shortcomings, such as quantitative error, high cost and complicated operation, etc. in NMR analysis; Logging is carried out after the borehole is formed and the drilling tool is raised, and the measurement time is relatively lagging behind; The equipment developed by universities and scientific research institutions has relatively high cost and complex structure. The Russian density and porosity tester for cuttings and cores has the advantages of simple operation, understandable principle, low cost, easy maintenance, wide applicability and strong real-time performance. As a supplement to the existing methods, it is necessary.
Definition of soil porosity
The coarse and fine soil particles of various shapes in the soil are assembled and arranged into a solid skeleton, and there are pores with different widths and shapes in the skeleton, which constitutes a complex pore system. The percentage of all pore volumes in the soil volume is called soil porosity.
experimental procedure
(1) sampling with a ring cutter with a volume of Vt, a ring cutter matching handle and a soil cutter, namely, the soil volume is vt;
(2) Take out the soil sample and weigh the wet weight of the soil sample with an electronic balance, Ms';
(3) drying the soil sample by means of heating drying, alcohol burning, freeze drying and the like;
(4) Calculate the water content of soil sample: w = (ms'-ms)/ms× 100%;
(5) putting the dried dry soil sample into a measuring cylinder filled with water, and measuring the volume VS of the dry soil sample by using the principle of drainage method;
(6) Calculate the soil bulk density d and density d by formulas (1) and (2);
(7) Based on the calculation of soil bulk density and density, calculate soil porosity by formula (3).
