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CN-122012840-A - Cavitation-resistant wear-resistant spheroidal graphite cast iron as well as preparation method and application thereof

CN122012840ACN 122012840 ACN122012840 ACN 122012840ACN-122012840-A

Abstract

The application relates to the technical field of metallurgical manufacturing, in particular to cavitation-resistant wear-resistant spheroidal graphite cast iron and a preparation method and application thereof, comprising the following steps of S1, smelting raw materials and preserving heat to obtain molten iron; the method comprises the steps of S2, adding a desulfurizing agent into the molten iron to carry out molten iron desulfurization treatment to obtain a desulfurized molten iron, S3, adding a spheroidizing agent into the desulfurized molten iron, covering slag collection to carry out spheroidization reaction to obtain a spheroidized molten iron, S4, adding a first inoculant into the spheroidized molten iron, then adding a second inoculant along with the flow to obtain an inoculated molten iron, S5, sequentially pouring and secondary annealing the inoculated molten iron, and cooling to obtain the cavitation-resistant wear-resistant spheroidal graphite cast iron, wherein the first inoculant is a Zr-Al-Si inoculant, and the second inoculant is a Ba-Sr-Si inoculant. The application obviously improves the toughness, wear resistance and cavitation resistance of the spheroidal graphite cast iron.

Inventors

  • MIAO CE
  • GE YINGHUA

Assignees

  • 宁波开发区安德鲁精铸有限公司

Dates

Publication Date
20260512
Application Date
20260210

Claims (9)

  1. 1. The preparation method of the cavitation-resistant wear-resistant spheroidal graphite cast iron is characterized by comprising the following steps of: s1, smelting and preserving heat of raw materials to obtain molten iron; S2, adding a desulfurizing agent into the molten iron to perform molten iron desulfurization treatment to obtain desulfurized molten iron; S3, adding a spheroidizing agent into the desulfurization iron liquid, covering slag collection for spheroidizing reaction to obtain spheroidized iron liquid; s4, adding a first inoculant into the spheroidized iron liquid, and then adding a second inoculant along with the flow to obtain an inoculated iron liquid; s5, pouring and secondary annealing are sequentially carried out on the inoculated iron liquid, and the cavitation-resistant and wear-resistant spheroidal graphite cast iron is obtained after cooling; The first inoculant is a Zr-Al-Si inoculant, and the second inoculant is a Ba-Sr-Si inoculant.
  2. 2. The preparation method of the cavitation-resistant wear-resistant spheroidal graphite cast iron according to claim 1, wherein in S1, alloy elements are added together with raw materials and participate in smelting, the addition amount of each alloy element accounts for 1.5-2.5% of nickel, 0.8-1.2% of chromium, 0.3-0.7% of molybdenum and 0.001-0.006% of boron by mass percent, the boron is added in a wetting way by phenolic resin, and the addition amount of the phenolic resin accounts for 0.5-3.0% of the addition amount of the boron.
  3. 3. The method for preparing the cavitation-resistant and wear-resistant spheroidal graphite cast iron according to claim 1, wherein in S2, the desulfurizing agent is a composite desulfurizing agent of CaO-Al 2 O 3 -MgO, and the dosage is 1.1% -2.0% of the total mass of the molten iron.
  4. 4. The method for preparing the cavitation-resistant and wear-resistant spheroidal graphite cast iron according to claim 3, wherein the composite desulfurizing agent comprises, by weight, 60-65 parts of CaO, 25-30 parts of Al 2 O 3 and 10-15 parts of MgO.
  5. 5. The method for preparing cavitation-preventing and wear-resisting spheroidal graphite cast iron according to claim 1, wherein in S3, the nodulizer is a composite nodulizer of Mg-RE-Ca, and the adding amount of the nodulizer is 1.0% -1.4% of the desulphurized molten iron.
  6. 6. The method for preparing the cavitation-resistant and wear-resistant spheroidal graphite cast iron according to claim 5, wherein the composite spheroidizing agent comprises, by weight, 4-8 parts of Mg, 1-3 parts of RE, 0.5-2 parts of Ca and the balance of ferrosilicon and unavoidable impurities, based on 100 parts of the total weight.
  7. 7. The method for preparing the cavitation-resistant and wear-resistant spheroidal graphite cast iron according to claim 1, wherein in S4, the addition amount of the first inoculant is 0.2% -0.4% of the mass of the spheroidized iron liquid, the addition amount of the second inoculant is 0.05% -0.15% of the mass of the spheroidized iron liquid, the standing reaction time of the first inoculant is 2.0-4.0min, and the addition of the second inoculant is completed synchronously with the pouring process.
  8. 8. The cavitation-resistant wear-resistant spheroidal graphite cast iron is characterized by being prepared by the preparation method of the cavitation-resistant wear-resistant spheroidal graphite cast iron according to any one of claims 1 to 7.
  9. 9. A fluid machinery flow passage component is characterized in that at least key friction or cavitation parts are made of cavitation-resistant wear-resistant spheroidal graphite cast iron according to claim 8, and the fluid machinery flow passage component is a valve core, a water pump impeller, a water turbine blade or a ship propeller.

Description

Cavitation-resistant wear-resistant spheroidal graphite cast iron as well as preparation method and application thereof Technical Field The application relates to the technical field of metallurgical manufacturing, in particular to cavitation-resistant wear-resistant spheroidal graphite cast iron and a preparation method and application thereof. Background Spheroidal graphite is obtained by spheroidization and inoculation, the mechanical property, in particular the plasticity and the toughness of cast iron are effectively improved, so that the strength higher than that of carbon steel is obtained, and the spheroidal graphite is used for replacing carbon steel, alloy steel and the like as an excellent engineering material and is widely applied to important parts such as crankshafts, gears, connecting rods, shells and valves of internal combustion engines. However, under high-speed fluid machinery (such as water pumps, water turbines, ship propellers and valves) and strong flushing conditions, cavitation damage and abrasion are easy to occur on the surfaces of parts. Cavitation erosion is the collapse of cavitation caused by the pressure change of fluid, micro-jet and shock waves are generated, fatigue peeling of the surface of a material is caused, and abrasion further aggravates the loss of the material. The traditional spheroidal graphite cast iron has the defect of cavitation erosion resistance and abrasion resistance, and the graphite phase, carbide morphology and spheroidal graphite cast iron toughness in the structure directly influence the durability. Disclosure of Invention In order to solve the problems, the application provides cavitation-resistant wear-resistant spheroidal graphite cast iron as well as a preparation method and application thereof. The application provides cavitation-resistant wear-resistant spheroidal graphite cast iron and a preparation method thereof, which adopt the following technical scheme: a preparation method of cavitation-resistant and wear-resistant spheroidal graphite cast iron comprises the following steps of S1 smelting raw materials and preserving heat to obtain molten iron, S2 adding a desulfurizing agent into the molten iron to carry out molten iron desulfurization treatment to obtain desulfurized molten iron, S3 adding a spheroidizing agent into the desulfurized molten iron to cover slag and carry out spheroidizing reaction to obtain spheroidized molten iron, S4 adding a first inoculant into the spheroidized molten iron, then adding a second inoculant along with flow to obtain an inoculated molten iron, S5 sequentially pouring, secondary annealing and cooling the inoculated molten iron to obtain the cavitation-resistant and wear-resistant spheroidal graphite cast iron, wherein the first inoculant is a Zr-Al-Si inoculant, and the second inoculant is a Ba-Sr-Si inoculant. By adopting the technical scheme, zr element in the first inoculant preferentially forms a high-melting-point heat-stable micro-compound, and the high-melting-point heat-stable micro-compound is used as a high-efficiency nucleation core to obviously increase the quantity of graphite nucleation, so that the graphite spheres are reduced in size and more uniformly distributed. As the coarse graphite and the graphite agglomeration area are micro areas where cavitation impact and abrasion cracks are most liable to occur, the tiny and round graphite structure formed by Zr-Al-Si inoculation can effectively reduce the stress concentration degree of a matrix interface, thereby reducing the initial formation of cavitation pits and inhibiting early abrasion and peeling. The Ba and Sr elements of the second inoculant have long effective action time and slow decay, can continuously inoculate in the later casting period and complex overflow parts, and can prevent the problems of graphite degradation, local white mouth and the like. Through the addition along with the flow, the graphite structure formed by the first inoculant can be stabilized and compensated, the graphite form at each part of the casting is ensured to be uniform and consistent with the hardness of the spheroidal graphite cast iron, the cavitation concentration and the uneven wear caused by local hard and brittle or softened areas are avoided, and finally, the stress concentration is effectively reduced and the crack expansion is blocked under the condition that the hardness is not simply improved, so that the toughness, the wear resistance and the cavitation resistance of the material are obviously improved. Preferably, in S1, alloy elements are added together with raw materials and participate in smelting, wherein the addition of each alloy element accounts for 1.5-2.5% of nickel, 0.8-1.2% of chromium, 0.3-0.7% of molybdenum and 0.001-0.006% of boron by mass percent of the raw materials, the boron is added in a manner of wetting by phenolic resin, and the addition of the phenolic resin accounts for 0.5-3.0% of the addition of boron. By adopting