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CN-121976116-A - Ductile cast iron for high-strength and high-toughness automobile brake calipers and preparation method thereof

CN121976116ACN 121976116 ACN121976116 ACN 121976116ACN-121976116-A

Abstract

The invention discloses a ductile iron for a high-strength and high-toughness automobile brake caliper and a preparation method thereof, wherein scrap steel and a ductile iron returns are selected as matrix raw materials for smelting, a carborundum stokehold thermal analyzer is adopted for component detection and fine adjustment of C, si, mn, cu, mo content in the smelting process, a rare earth silicon magnesium iron alloy nodulizer is added into a nodulizing ladle, iron powder or scrap steel sheets are covered on the nodulizer, a silicon barium calcium inoculant is added into the nodulizer for ladle inoculation, the spheroidizing inoculation reaction temperature is controlled to be 1400-1430 ℃, the treated molten iron is poured into a brake caliper casting mold, stream inoculation is synchronously carried out in the pouring process, the adding amount of the stream inoculant is 0.15-0.2% of the total mass of the molten iron, and the molten iron is naturally cooled to room temperature after filling to obtain the brake caliper ductile iron.

Inventors

  • XIAO ZHIYU
  • LIN ZHENGQI
  • SU JIANYONG
  • TIAN CHAOQUN
  • YANG ZHONGLIN
  • Lv Cuibi

Assignees

  • 华南理工大学
  • 广东韶铸精密机械有限公司

Dates

Publication Date
20260505
Application Date
20251229

Claims (9)

  1. 1. The nodular cast iron for the automobile brake calipers is characterized by comprising the following chemical components in percentage by mass: C:3.4%–3.8%; Si:2.2-2.7%; Mn:0.35%–0.55%; Cu:0.65%–0.75%; Mo:0.1%–0.2%; Mg:0.035%–0.060%; P≤0.02%; S≤0.02%; the balance being Fe.
  2. 2. The nodular cast iron for the automobile brake calipers is characterized by comprising the following chemical components, by mass, 3.6% of C, 2.4% of Si, 0.45% of Mn, 0.70% of Cu, 0.15% of Mo, 0.045% of Mg, less than or equal to 0.02% of P, less than or equal to 0.015% of S and the balance of Fe.
  3. 3. A preparation method of ductile cast iron for high-strength and high-toughness automobile brake calipers is characterized by comprising the following steps: S1, selecting scrap steel and spheroidal graphite cast iron as a base raw material, and adding copper, manganese, molybdenum alloy or intermediate alloy and carburant according to target components, and weighing according to a proportion for standby; S2, adding the substrate raw material into an intermediate frequency induction furnace for smelting, adopting a carbon-silicon stokehold thermal analyzer for component detection in the smelting process, and performing fine adjustment on C, si, mn, cu, mo content to enable the content to meet a set component range; And S3, adding a rare earth silicon magnesium iron alloy nodulizer into the nodulizing ladle, covering iron powder or scrap steel sheets on the nodulizer, adding a silicon barium calcium inoculant for ladle inoculation, controlling the nodulizing inoculation reaction temperature to be 1400-1430 ℃, pouring the treated molten iron into a brake caliper casting mold, synchronously carrying out stream inoculation in the pouring process, and naturally cooling to room temperature after filling to obtain the brake caliper nodular cast iron, wherein the adding amount of the stream inoculant is 0.15-0.2% of the total mass of the molten iron.
  4. 4. The method for producing ductile iron for automotive brake calipers according to claim 1 wherein the molten iron temperature in the melting process in step S1 is 1500-1540 ℃.
  5. 5. The method for preparing ductile iron for high strength and toughness automobile brake calipers according to claim 1, wherein in the step S3, the adding amount of the rare earth silicon magnesium iron alloy nodulizer is 0.9% -1.3% of the total mass of molten iron.
  6. 6. The method for preparing ductile iron for high strength and toughness automobile brake calipers according to claim 1, wherein in the step S3, the adding amount of the silicon-barium-calcium inoculant is 0.4% -0.6% of the total mass of molten iron.
  7. 7. The method for preparing ductile iron for high strength and toughness automotive brake calipers according to claim 1, wherein in the step S3, the treated molten iron is poured into a brake caliper casting mold under the pouring conditions of the pouring temperature of 1360-1400 ℃ and the pouring time of 10-12 seconds.
  8. 8. The method for preparing ductile iron for high strength and toughness automobile brake calipers according to claim 1, wherein the cast iron in step S3 is subjected to shakeout, cleaning and shot blasting to obtain a finished product.
  9. 9. A high strength and toughness spheroidal graphite cast for automotive brake calipers, characterized in that it is obtained by the preparation method according to any one of claims 3 to 8.

Description

Ductile cast iron for high-strength and high-toughness automobile brake calipers and preparation method thereof Technical Field The invention relates to the technical field of cast metal materials, in particular to ductile cast iron for a high-strength and high-toughness automobile brake caliper and a preparation method thereof. Background The automobile brake caliper is a key bearing and executing component in a disc brake system, and needs to bear periodic mechanical load, clamping force and thermal-mechanical coupling working condition for a long time in the service process, so that higher requirements are provided for the tensile strength, yield strength, elongation, fatigue performance and casting compactness of the material. The ductile cast iron has low cost, excellent casting performance and comprehensive mechanical property close to steel, and is widely used for manufacturing brake calipers. In the prior art, the strength of spheroidal graphite cast iron for the brake calipers is improved in a single or simple alloying mode, but the problems that the strength and the plasticity are difficult to be compatible, shrinkage cavities and shrinkage porosity are easy to occur at thick or hot joint positions, the tissue stability is insufficient and the like are often existed. Especially under the trend of light design, the caliper structure tends to be complex, the wall thickness difference is increased, and higher requirements are put on the self-feeding capability and the tissue uniformity of the material. Therefore, it is necessary to provide a new alloy system and a preparation method, and the strength, plasticity and tissue stability of the spheroidal graphite cast iron for the brake calipers are comprehensively improved on the premise of ensuring good casting performance and compactness through the synergistic effect of Cu-Mn-Mo multi-element alloying. Disclosure of Invention The invention aims to overcome the defects and shortcomings of the prior art and provide ductile cast iron for a high-strength and high-toughness automobile brake caliper and a preparation method thereof. Solves the problem that the existing spheroidal graphite cast iron for brake calipers has poor comprehensive properties such as strength, plasticity, tissue stability and the like. The invention is realized by the following technical scheme: The nodular cast iron for the automobile brake calipers comprises the following chemical components in percentage by mass, wherein the balance of ：C：3.4％–3.8％、Si：2.2-2.7％、Mn：0.35％–0.55％、Cu：0.65％–0.75％、Mo：0.1％–0.2％、Mg：0.035％–0.060％、P≤0.02％、S≤0.02％、 is Fe and unavoidable impurities; preferably, the alloy comprises 3.6% of C, 2.4% of Si, 0.45% of Mn, 0.70% of Cu, 0.15% of Mo, 0.045% of Mg, less than or equal to 0.02% of P, less than or equal to 0.015% of S, and the balance of Fe. A preparation method of ductile cast iron for high-strength and high-toughness automobile brake calipers comprises the following steps: S1, selecting scrap steel and spheroidal graphite cast iron as a base raw material, and adding copper, manganese, molybdenum alloy or intermediate alloy and carburant according to target components, and weighing according to a proportion for standby; S2, adding the substrate raw material into an intermediate frequency induction furnace for smelting, adopting a carbon-silicon stokehold thermal analyzer for component detection in the smelting process, and performing fine adjustment on C, si, mn, cu, mo content to enable the content to meet a set component range; S3, adding a rare earth silicon magnesium iron alloy nodulizer into the nodulizing ladle, covering iron powder or scrap steel sheets on the nodulizer, adding a silicon barium calcium inoculant for ladle inoculation, controlling the nodulizing inoculation reaction temperature to be 1400-1430 ℃, pouring the treated molten iron into a brake caliper casting mold, synchronously carrying out stream inoculation in the pouring process, wherein the addition amount of the stream inoculant is 0.15-0.2% of the total mass of the molten iron so as to enhance the inoculation effect and inhibit inoculation degradation, and naturally cooling to room temperature after filling to obtain brake caliper spheroidal graphite cast iron (casting); In the smelting process in the step S1, the temperature of molten iron is 1500-1540 ℃. And the addition amount of the rare earth silicon magnesium iron alloy nodulizer in the step S3 is 0.9-1.3% of the total mass of molten iron. And the adding amount of the silicon-barium-calcium inoculation agent in the step S3 is 0.4-0.6% of the total mass of molten iron. And step S3, pouring the treated molten iron into a brake caliper casting mold, wherein the pouring temperature is 1360-1400 ℃ and the pouring time is 10-12 seconds. And step S3, performing shakeout, cleaning and shot blasting treatment on the cast iron (casting) to obtain a finished product. The high-strength and high-toughness spheroidal graphite cast for