This study developed the cemented tungsten carbide by steadily sintering at 1430 °C for one hour. The tungsten carbide structure is a long shape. Its grain size has a difference between width and length and there are high distribution of sizes and shapes. In comparison with the work piece which has the similar size of grain structure the milling duration of tungsten carbide is less even though the condition of WC-Co is the same (95% WC – 5% Co). When the sintering of 1400 °C with the identical milling duration is performed. It turned out that both grain structures of the tungsten carbide and the work piece are similar and their grain sizes are slightly different. However when the grain structures are almost the same and sphericity is increased the hardness and wear resistance will also be improved. Therefore the size of grain structure between 1.00 – 3.00 μm with the milling duration of 100 hours will provide a work piece that has a wear resistance according to international standard

This study aims to development of production process of hard metal by tungsten carbide powder with the particle sized of 0.1 - 0.35 µm. This carbide powder were made of recycling cemented carbide tool scraps so it is mixed with Ta = 2.82 % Mo = 0.45 % Nb = 1.22 % Ti = 4.56 % Zr = 0.37 % The shape of the carbide powder are roughly round due to ball milling for 300 hours. It was mixing cobalt 10 % and Paraffin wax 2 % which is found the work piece that running through the process of sintering with a temperature of 1400 °c and 1430 °c have the hardness of 1368.5 and 1346.3 HV respectively. In one hour of holding time process the work piece with 1430 °c of the sintering causes less wear. After the test of turning operation it can be concluded that the tungsten carbide cutting tool provides the equivalent quality as a standard cutting tool.

The research aims to investigate the possibilities of crushed oyster shell (OS) not have to go through the process of burning as a substitution cement for concrete blocks. The cement was replaced with crushed oyster shell not process burning (OS) at 0% 10203040 and 50% by the weight of the binder. After that the concrete blocks were tested to determine the compressive strength and moisture absorbed of the concrete blocks cured for 7 142856 and 90 days The result showed that the compressive strength of the concrete blocks which replaced cement with OS (at the proportion of 10% by the weight of the binder) at 28 days had the compressive strength and water absorbed accordance with the TIS 58-2533 on non-load bearing concrete blocks.Moreover the concrete blocks which replaced cement with OS at the proportion of 20 % and 30 % had the compressive strength equivalent to 28 days compressive strength of TIS 58-2533 standard at 56 and 90 days respectively and decreased when the percentage in addition to OS in concrete blocks of 40 and 50 %. Tested results also showed that the water absorbed of concrete blocks increased when the percentage of replacement of OS in binder increased at 10 20 30 40 and 50%. The economical of concrete blocks it has manufactured unit cost is 2.60 baht. Whereas the concrete block containing crushed oyster shell at 10-30% it has manufactured unit cost at 2.12-2.44 baht respectively.

The tungsten carbide powder which recycled from the scarps of cemented tungsten carbide produces the purity of 99%. Using this tungsten carbide powder to manufacture a cutting tool and test its properties are the main objective of this work. Based on the standard SNMG 120408 the cutting tool with the dimension of 12.7x12.7x4.76 is fabricated. With the 100 hours of Ball milling grinding Cobalt mixing and sintering at 1430 °C the experimental result is impressive. At 15% of mixedcobalt the cutting tool with the hardness of 2031.6 HV be able to cut S45C steel in the feed rate of 0.2 meters per revolution and 45 m/min in the cutting speed. Besides that it provides the depth of cut of 0.25 mm and when it reaches the cutting distance of 4200 mm the surface roughness is 3.65 μm. In comparison with the cutting tool made of imported tungsten carbide powder which has a hardness of 1254 HV it turned out that our cutting tool has the equivalent quality in terms of hardness and wear resistance. Hence this work is considered to be a material development and a tungsten carbide cutting tool manufacture those would be the vital base to lead us to a commercial production.