Implementation standards for detecting cemented carbide porosity using metallographic microscopes
The implementation standard for metallographic microscope detection of cemented carbide porosity is GB/T 3489-2015 Metallographic determination of cemented carbide porosity and non-combined carbon. The detection steps are as follows:
1. The maximum size of the pores on the grinding surface is determined as the size of the pores.
2. For pores less than or equal to 10um, observe the grinding surface of the sample at 100 or 200 times magnification for evaluation.
3. For pores larger than 10um and smaller than 25um, observe the polished surface of the sample under a metallographic microscope at 100 times magnification and evaluate it.
4. If it is necessary to inspect pores larger than 25um, the inspection should be carried out under a metallographic microscope with an appropriate magnification of less than or equal to 100 times.
5. If the porosity or non-combined carbon is unevenly distributed on the grinding surface of the metallographic sample for inspection, its location must be identified, such as the top, top, edge (shell) and center, etc.
There are relatively many detection methods for rock cuttings and core porosity. In well logging, rock cuttings and core porosity can be measured by drilling logging, microscopic examination of rock cuttings, and nuclear magnetic resonance analysis. In well logging, compensated neutron, compensated density, and acoustic transit time logging are commonly used methods to measure porosity. Some universities and scientific research institutions have also developed specialized equipment for measuring cuttings porosity. Logging during drilling and microscopic inspection of cuttings have shortcomings such as inability to quantify and large errors. NMR analysis has shortcomings such as high cost and cumbersome operation. Well logging is performed after the wellbore is formed and the drilling tools are proposed. The measurement time is Relatively lagging behind; the cost of equipment developed by universities and scientific research institutions is relatively high and the structure is relatively complex. The Russian cutting and core density porosimeter has the advantages of simple operation, easy to understand principles, low cost, easy maintenance, wide applicability, and strong real-time performance. It is necessary to supplement existing methods.
soil porosity definition
Thick and fine soil particles of various shapes in the soil are collected and arranged into a solid skeleton. There are 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) Use a ring knife with a volume of Vt, use the ring knife with a matching handle, and a soil cutter for sampling, that is, 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) Dry soil samples using heating drying, alcohol burning, freeze drying, etc.;
(4) Calculate the moisture content of the soil sample: w= (ms'-ms)/ms×100%;
(5) Put the dried soil sample into a measuring cylinder filled with 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 according to formulas (1) and (2);
(7) Based on the calculation of soil bulk density and density, the soil porosity is calculated by formula (3).
