Plunger pump and pump cylinder material how to choose

Plunger pump and pump cylinder material how to choose? Ultimately, from the pump standpoint, the choice of materials for the barrel and plunger and the choice of finishing process are decisive factors in determining the amount of wear and tear on the tribological system. At present, the number of wells in the domestic oilfield using rod pumps accounts for a large proportion, most of which are plunger pumps. Conventional plunger pumps have become one of the major oil recovery methods. Plunger pump plunger and plunger wear, corrosion, scratches more and more serious, the average well pump inspection cycle is shorter and shorter, and some even less than 30 days you need to check the pump, as most of the domestic oil field has In the period of high water cut, coupled with factors such as high sand content, high temperature steam heavy oil exploitation, polymer injection and strong corrosive medium conditions and poor well conditions, the comprehensive economic benefits of oilfield development are seriously affected. Many institutions at home and abroad have invested a lot of effort to study the cause of pump failure and protective measures. One of the most effective methods is to optimize the material and finish of the pump barrel and plunger. Plunger Oil pump pump and cylinder friction pairs and the surrounding work environment and conditions constitute a tribological system, the corrosion of the system by the plunger pump plunger pump corrosion and wear and tear and corrosion of the plunger wear The sum of the amount of the decision. The respective wear and tear on the barrel and plunger are determined by the physical-mechanical-chemical properties of the constituent materials, the relationship of their mutual motions, working conditions and conditions. The purpose of selecting and optimizing the pump barrel and plunger material and surface treatment processes for the plunger pump is to minimize the amount of corrosion wear on the tribology system. Due to a large number of factors, so there is still no theoretical guidance on the material selection and matching of the pump cylinder and the plunger. The most important work done by R & D personnel at present is to select the material and surface treatment process of various pump cylinders and plungers, Wear indoor friction and wear test conditions, from the test results to determine in this test conditions, what kind of pump plunger plunger material should be selected. Here are two test results: The first result: The plunger pump plunger material and surface treatment process for the 45 steel surface electroless nickel-phosphorus alloy, 303 steel chrome, 4% -6% chromium steel pressure nitriding 3 kinds of plunger material and table processing technology for the carbon steel chrome, carbon steel laser treatment, navy brass electroless nickel-phosphorus alloy, Monel alloy chrome and other four kinds. The above materials were paired abrasion resistance test, the friction pair for the test by the ring and block composition. The medium is water, the temperature is 60 ℃ and the viscosity is 0.000653Pa / s. Testing machine for MG-200 high-speed high-temperature friction and wear testing machine. The applied load 1kN, specimen total friction stroke of 20km. Through the pair of different cylinder and plunger material and surface treatment process of paired abrasion resistance test research, and according to the principle of plunger failure principle for the selection of pump cylinder and plunger friction pair are the best matching material carbon steel chemistry Nickel-phosphorus alloy and carbon steel chrome plating. The second result: the plunger barrel pump material and surface treatment process for the carbon steel surface chrome, carbon steel surface electroless nickel-phosphorus alloy and 38CrMoAl nitriding; plunger material and surface treatment of carbon steel surface chrome, carbon Nickel-phosphorus alloy steel surface chemical plating, carbon steel surface spray welding nickel-based alloy and 38CrMoAl nitriding, were paired into nine pairs of friction pair. Test friction pair by the ring and column. The test medium is oily wastewater containing 5% oil; the mineral content in the water is chloride ion 11000mg / 1, carbon dioxide 25mg / 1, calcium ion 25mg / 1, bicarbonate ion 30mg / 1, magnesium ion 13mg / 1, 8mg / 1; sand 0.4%; temperature 60 ℃. The same use of domestic MG-200 high-speed high temperature friction and wear testing machine. Test load 100N, the total friction of about 6km. Comprehensive analysis of test results, that the carbon steel spray plunger and carbon steel chrome-plated plunger pump cylinder paired as the best, 38CrMoAI nitriding plunger and carbon steel chrome-plated pump cylinder paired. As can be seen above, the laboratory test results are obtained under the set conditions. If different test conditions are changed, the workload will be huge. Even if the conditions of the changes are different, it is not necessarily consistent with the downhole conditions in the field. Therefore, the experimental results have limitations. Due to the different test conditions and the shape of the friction pair, there is no comparability among the test results. With the development of material engineering and the emergence of new material surface treatment technology, many materials and surface treatment processes are likely to be applied to the surface of the barrel and plunger of the plunger pump, by a simple laboratory friction and wear test of paired materials To decide the trade-off is far from meeting the urgent requirements to improve the pump barrel and plunger life expectancy. How to design pump barrel and plunger matching materials by means of material science and other disciplines principles and techniques is an urgent issue to be solved. It can be seen through the experiment to determine the plunger pump plunger and plunger material match its deficiencies, there is no theoretical guidance test Therefore a great deal of work. The material chosen for the test is only the well-known material already available and it is difficult to come up with other materials that may not have been used on the pump but may perform better.