Metallographic Microscopy Testing of Porosity in Cemented Carbides
1. The maximum size of the pores on the grinding surface is determined as the size of the pores.
2. For pores smaller than or equal to 10um, observe the worn surface of the sample under magnification of 100 or 200 times for evaluation.
3. For pores larger than 10um but smaller than 25um, observe the worn surface of the sample under a metallographic microscope at a magnification of 100x and evaluate it.
4. If it is necessary to inspect pores larger than 25um, the inspection should be carried out under a metallographic microscope at an appropriate magnification of less than or equal to 100 times.
5. If the porosity or non compounded carbon is unevenly distributed on the ground surface of the inspected metallographic specimen, its position must be identified, such as the top, top, edge (shell), and center.
There are relatively many methods for detecting the porosity of rock cuttings and cores. In logging, drilling mud logging, microscopic examination of rock cuttings, and nuclear magnetic resonance analysis can measure the porosity of rock cuttings and cores. In logging, compensated neutron, compensated density, and acoustic time difference logging are commonly used methods for measuring porosity. Some universities and research institutions have also developed specialized equipment for measuring rock debris porosity. There are shortcomings such as inability to quantify and large errors in drilling mud logging and microscopic examination of rock cuttings, as well as high costs and cumbersome operations in nuclear magnetic resonance analysis; Logging is performed after the formation of the wellbore and the removal of drilling tools, with a relatively delayed measurement time; The equipment developed by universities and research institutions has a relatively high cost and a relatively complex structure. The Russian rock debris and core density porosity tester has the advantages of simple operation, easy to understand principle, low cost, easy maintenance, wide applicability, and strong real-time performance. As a supplement to existing methods, it is necessary.
Definition of soil porosity
The collection and arrangement of various shapes of coarse and fine soil particles in the soil form a solid skeleton, with pores of different widths and shapes inside the skeleton, forming a complex pore system. The percentage of the total pore volume in the soil volume is called soil porosity.
Experimental steps
(1) Using a ring knife with a volume of Vt, using a ring knife with a handle and a soil cutting knife to sample, i.e. the soil volume is Vt;
(2) Take out the soil sample and use an electronic balance to weigh the wet weight ms' of the soil sample;
(3) Drying soil samples using methods such as heating and drying, alcohol burning, and freeze-drying;
(4) Calculate the moisture content of the soil sample: w=(ms' - ms)/ms × 100%;
(5) Place the dried dry soil sample into a measuring cylinder containing water, and measure the volume Vs of the dry soil sample using the principle of drainage method;
(6) Calculate soil bulk density D and density d using formulas (1) and (2);
(7) Based on the calculation of soil bulk density and density, calculate soil porosity using formula (3).
