Hard Alloy for Wear-resisting and Acid Resistant and Acid Resistant Drilling

With the continuous development of the hard alloy industry and the quickening of the pace of deep-sea engineering, the exploration of oil and gas is becoming more complex in the geological conditions and physical environment. Some areas with high H₂S and CO₂ content and high sulfur bearing geological environment have become the focus of oil and gas exploration, and this has also raised higher requirements for the hard joint gold for drilling.

In order to solve the existing technical problems of hard alloy strength, abrasion resistance and toughness, a solution is proposed by researchers, which include the following process steps: mixing, wet grinding, drying of admixture, granulating, pressing molding and vacuum low pressure integrated sintering.

(1) The mass ratio of nickel powder to tungsten carbide powder is 5:95. Tungsten carbide mixed powder is made of conventional tungsten carbide powder with Fsss particle size of 6.8μm and tungsten carbide powder with 2 μm particle size as 50:50 mixture. The carbon content (total carbon) 6.12wt% of the conventional tungsten carbide powder and the carbon content (total carbon) 3.2wt% of the cast tungsten carbide powder. The particle size of the nickel powder is 1.25 μm.

(2) When wet milling is used for ball milling, the ball milling medium for wet grinding is acetone and n-hexane, the ratio of ball to material is 3.3:1, the ratio of solid to liquid is 4.2:1, and the wet grinding time is 26 hours.

(3) After wet grinding, paraffin wax was heated to 58°C and rolled for 25 minutes. After drying, granulating, pressing and forming, and vacuum low pressure integrated sintering, the highest temperature of vacuum low pressure integrated sintering is 1640°C.

(4) The obtained wear resistant hard alloy (the standard product of the size of 6.5 x 5.25 x 20 μm) was tested with 100 samples. The average bending strength was 2800MPa, the average hardness was HRA90.6, and the corrosion resistance was excellent.

Through the common sintering of tungsten carbide powder, cast tungsten carbide powder and nickel powder, the strength of the bonding phase and the intergranular microstructure are improved, the toughness and abrasion resistance of the alloy are improved, and the impact resistance of the alloy is improved greatly. The wear resistance and impact toughness of the alloy are greatly improved, the bending strength and the strength of the alloy are greatly improved. Excellent hardness, good matching of strength and microhardness, thus greatly improving the comprehensive properties of the alloy. The wear-resistant and corrosion hard alloy products can effectively improve the wear resistance, corrosion resistance and toughness of mechanical parts and prolong the service life. It has a broad application prospect in the field of deep-sea oil drilling, marine equipment, geology, mine, engineering machinery and Aeronautics.

The bed strip in the coarse selection is higher than the convex area formed in the middle selection area and the selected area and the movable bed strip, forming the flow drop of the tungsten mine paddle fluid, increasing the fluid pressure, making the tungsten ore particles fully loose and improving the loose efficiency of the grain. In addition, the long edge of the bed strip in the middle selection area has two sizes, the larger long edge ruler. The length is smaller than the long side value of the bed surface, forming a stepped middle section, increasing the transverse force of the water flow, and further separating the tailings. At the same time, according to the separation of tungsten ores from the longitudinal grooves of the coarse selection, appropriate number of bed bars are placed in the proper position in the proper position of the movable bed strip below the water chute, the left of the coarse selection area and the middle selection area, so as to realize the further separation of the pulp in the selected area and near the coarse selection. It has been proved by practice. With the optimized scheme, the bed obtained by the optimized bed has good separation effect and can clearly distinguish the high, medium and low grade tungsten ores. 

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