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CN-121992287-A - Casting method of austempered ductile iron wind power planet carrier

CN121992287ACN 121992287 ACN121992287 ACN 121992287ACN-121992287-A

Abstract

The invention relates to a casting method of an austempered ductile iron wind power planetary support, which selects an austempered ductile iron to manufacture the wind power planetary support, wherein the austempered ductile iron is based on spheroidal graphite cast iron, and the spheroidal graphite cast iron comprises ：C：3.50-3.70%,Si：2.50-2.70%,Mn：<0.30%,P：<0.03%,S：<0.02%,Mg：0.035-0.055%,Re：0.01-0.02%,Cu：0.60-0.80%,Mo：0.30-0.40%,Mn+Mo percent of spheroidal graphite cast iron in parts by weight (weight ratio (%)) with the total amount less than 0.5 percent so as to greatly improve the service life, and meanwhile, the purposes of energy conservation, weight reduction and material saving (generally, weight reduction can be 1/4-1/3) can be achieved.

Inventors

  • XU HUIMIN
  • ZHAO TONGQING
  • CHEN YANG
  • WANG LIE

Assignees

  • 惠尔信机械（泰兴）有限公司

Dates

Publication Date
20260508
Application Date
20251223

Claims (5)

  1. 1. A casting method of an austempered ductile iron wind power planetary support is characterized in that an austempered ductile iron is selected to manufacture the wind power planetary support, the austempered ductile iron is based on spheroidal graphite cast iron, and the spheroidal graphite cast iron comprises the following ：C：3.50-3.70%,Si：2.50-2.70%,Mn：<0.30%,P：<0.03%,S：<0.02%,Mg：0.035-0.055%,Re：0.01-0.02%,Cu：0.60-0.80%,Mo：0.30-0.40%,Mn+Mo percent by weight of the spheroidal graphite cast iron with the total weight less than 0.5 percent.
  2. 2. The casting method of the austempered ductile iron wind power planet carrier according to claim 1, comprising: Firstly, smelting ductile iron molten iron by an induction furnace, wherein the tapping temperature is 1480-1500 ℃; step two, spheroidizing the ductile cast iron liquid after discharging from the furnace, inoculating, and the chemical composition requirements of the treated liquid iron are as follows: C：3.50-3.70%,Si：2.50-2.70%,Mn：<0.30%,P：<0.03%,S：<0.02%,Mg：0.035-0.055%,Re：0.01-0.02%,Cu：0.60-0.80%,Mo：0.30-0.40%,Mn+Mo The total amount is less than 0.5%; Step three, the molten iron treated in the step two is subjected to a sand-lined iron mold molding process to obtain a blank of the wind power planet carrier; machining the part casting blank obtained in the third step, and reserving a deformation allowance; carrying out isothermal quenching treatment on the wind power planet carrier subjected to mechanical processing in the step four: austenitizing and heating to 890-910 ℃ for 5-6h; isothermal quenching temperature is 350-370 ℃ and time is 1-2h; The metallurgical structure of the basal body of the part after the isothermal quenching treatment is acicular ferrite, carbon-rich austenite and spherical graphite, and the mechanical property of the basal body is that the tensile strength (sigma b) is 810-990N/mm < 3 >, the elongation (delta) is 6.0-10.0%, and the Brinell Hardness (HB) is 260-310; and step six, performing metallographic examination on the part subjected to the isothermal quenching treatment, and obtaining a finished product if the part is qualified.
  3. 3. The casting method of austempered ductile iron wind power planet carrier according to claim 2 wherein the isothermal quenching heat treatment of the parts in the fifth step is performed in a salt bath, and the salt used as the quenching medium is potassium nitrate and sodium nitrate, and the addition ratio of the salt to the quenching medium is 50% respectively.
  4. 4. The casting method of the austempered ductile iron wind power planet carrier according to claim 2, wherein the as-cast microstructure of the ductile iron is pearlite ductile iron, the pearlite content is more than 80%, the spheroidization rate is 2-3 grades, and the graphite nodules are 5-7 grades in size.
  5. 5. Use of an austempered ductile iron as defined in claim 1 in a wind power planet carrier.

Description

Casting method of austempered ductile iron wind power planet carrier Technical Field The invention relates to the technical field of casting, in particular to a casting method of an austempered ductile iron wind power planet carrier. Background As known in the art, the conventional wind power planet carrier is formed by casting common pearlitic ductile iron (QT 700-2 or QT 800-2) by adopting a resin sand process. The working environment (strong wind, cold, humidity and the like) of the wind turbine generator is bad, and the planet carrier bears the reciprocating circulation action of random amplitude load for a long time along with irregular shock of wind speed, so that the service life of the planet carrier is influenced in actual operation, and the design life of the planet carrier cannot be reached. Meanwhile, due to the fact that the material performance is limited, the wind power planet carrier is quite thick and large in design, and the power consumption of the unit can be correspondingly increased. Under the background, the new ultra-high performance metal material is adopted to improve the service performance and reliability, thereby achieving the purposes of saving energy (saving electricity), saving materials (reducing weight) and prolonging the service life. The isothermal quenching ductile iron engineering material has the advantages of good comprehensive mechanical properties (shown in Table 1), good wear resistance and high yield ratio. TABLE 1 It is particularly pointed out that austempered ductile iron has excellent wear resistance and abrasion resistance. A large number of tests show that the isothermal quenching ductile iron has better wear resistance than the common ductile iron with the same hardness. This is because the matrix structure is acicular ferrite having high hardness and a carbon-rich austenite structure having a work hardening effect. Disclosure of Invention The invention aims to improve the usability and reliability of the existing wind power planet carrier material, so as to achieve the purposes of saving energy (saving electricity), saving materials (reducing weight) and prolonging the service life of the wind power planet carrier, and provides a casting method of an austempered ductile iron wind power planet carrier. The invention firstly provides an austempered ductile iron engineering material which is based on ductile cast iron, and comprises the following components in parts by weight: C：3.50-3.70%,Si：2.50-2.70%,Mn：<0.30%,P：<0.03%,S：<0.02%,Mg：0.035-0.055%,Re：0.01-0.02%,Cu：0.60-0.80%,Mo：0.30-0.40%,Mn+Mo The total amount is less than 0.5%. The invention also provides a casting method of the austempered ductile iron wind power planet carrier, which comprises the following steps: Firstly, smelting ductile iron molten iron by an induction furnace, wherein the tapping temperature is 1480-1500 ℃; step two, spheroidizing the ductile cast iron liquid after discharging from the furnace, inoculating, and the chemical composition requirements of the treated liquid iron are as follows: C：3.50-3.70%,Si：2.50-2.70%,Mn：<0.30%,P：<0.03%,S：<0.02%,Mg：0.035-0.055%,Re：0.01-0.02%,Cu：0.60-0.80%,Mo：0.30-0.40%,Mn+Mo The total amount is less than 0.5%; Step three, the molten iron treated in the step two is subjected to a sand-lined iron mold molding process to obtain a blank of the wind power planet carrier; machining the part casting blank obtained in the third step, and reserving a deformation allowance; carrying out isothermal quenching treatment on the wind power planet carrier subjected to mechanical processing in the step four: austenitizing and heating to 890-910 ℃ for 5-6h; isothermal quenching temperature is 350-370 ℃ and time is 1-2h; The matrix metallographic structure of the above part after the isothermal quenching treatment is acicular ferrite, carbon-rich austenite and spheroidal graphite, and the mechanical property of the matrix is that the tensile strength (sigma b) is 810-990MPa, the elongation (delta) is 6.0-10.0%, and the Brinell Hardness (HB) is 260-310; and step six, performing metallographic examination on the part subjected to the isothermal quenching treatment, and obtaining a finished product if the part is qualified. The isothermal quenching heat treatment of the parts in the fifth step is carried out in a salt bath, and the salt used as a quenching medium is potassium nitrate and sodium nitrate, and the addition ratio of the salt to the quenching medium is 50 percent. The as-cast microstructure of the nodular cast iron is pearlite ductile iron. The content of pearlite is more than 80%, the spheroidization rate is 2-3 grade, and the graphite nodule size is 5-7 grade. The invention also provides application of the austempered ductile iron to a wind power planet carrier. The invention has the beneficial effects that: The invention firstly provides a casting method of an austempered ductile iron wind power planet carrier, which is based on ductile iron and comprises the