CN112553413A - Planet carrier, casting material and heat treatment process thereof - Google Patents

Planet carrier, casting material and heat treatment process thereof Download PDF

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Publication number
CN112553413A
CN112553413A CN202011309221.9A CN202011309221A CN112553413A CN 112553413 A CN112553413 A CN 112553413A CN 202011309221 A CN202011309221 A CN 202011309221A CN 112553413 A CN112553413 A CN 112553413A
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quenching
workpiece
thick
cooling
equal
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CN112553413B (en
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刘显有
肖章玉
李川
马正强
程湘
张军宝
曾国成
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China Erzhong Group Deyang Heavy Industries Co Ltd
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China Erzhong Group Deyang Heavy Industries Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H57/00—General details of gearing
    • F16H57/08—General details of gearing of gearings with members having orbital motion
    • F16H57/082—Planet carriers
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite

Abstract

The invention relates to the technical field of heat treatment of materials, in particular to a planet carrier, a casting material and a heat treatment process thereof. The heat treatment method comprises the steps of completely immersing a workpiece into quenching liquid for cooling, exposing the thin part of the workpiece to the liquid level after the thin part of the workpiece meets the quenching requirement, continuously performing immersion cooling on the thick part of the workpiece, enabling the workpiece to enter a semi-immersion quenching state, enabling the whole workpiece to leave the quenching liquid after the thick part of the workpiece is quenched, and finishing the quenching process. By the method, the thin part and the thick part can reach the optimal quenching time, the hardness uniformity of the workpiece is improved to the maximum extent under the condition that the workpiece reaches high performance, and the quality risks of deformation, cracking and the like are reduced. The heat treatment method can be widely applied to the heat treatment of water quenching, oil quenching and the like of castings, forgings and machined parts with larger thickness difference.

Description

Planet carrier, casting material and heat treatment process thereof
Technical Field
The invention relates to the technical field of heat treatment of materials, in particular to a planet carrier, a casting material and a heat treatment process thereof.
Background
Quenching is one of the most common heat treatment processes for metals, and for workpieces with complex structures and large thickness difference, the quality problems of unqualified performance, uneven hardness and product cracking and deformation exist in the conventional quenching and tempering heat treatment mode. If the quenching time determined by the thin part is carried out on the whole workpiece, and the liquid cooling time is short during quenching, the quality problems of high final cooling temperature and low hardness of the thick part can occur; if the quenching time determined by the thick part is carried out on the whole workpiece, and the liquid cooling time is long during quenching, the final cooling temperature of the thin part is too low, the hardness of the thin part is higher, and the quality risk of cracking and deformation of the thin part due to tissue stress and thermal stress is increased; if the integral quenching time of the workpiece is between the quenching time of the two conditions, the thin-wall part has high hardness, the thick-wall part has low hardness, the integral hardness uniformity is poor, and the quality problems of large casting quenching cracking and deformation still exist.
As shown in fig. 1, a wind power planet carrier casting is taken as an example. The wind power speed increasing box is a core component in a wind power unit, a large wind power gear box mostly adopts planetary transmission, and is typical low-speed, heavy-load, torque-variable and speed-increasing transmission, the planet carrier has a complex structure, a large size and a maximum bearing torque, and the deformation of the planet carrier has great influence on the quality and reliability of the transmission of the internal and external meshing gears of the planet stage. The planet carrier must have sufficient strength, rigidity and certain toughness. The planet carrier casting is made of low-carbon low-alloy cast steel, and the low-carbon low-alloy high-strength high-low-temperature toughness cast steel disclosed in the patent application with the publication number of CN107475487A can be used for the wind power planet carrier. However, the planet carrier has a complex structure and a large size, the difference of the thickness position thermal junctions is large, the difference of the wall thickness of the upper section and the lower section is large, and quality risks such as uneven hardness, deformation, cracking and the like are easily caused during quenching.
On page 134 of "thermal processing" (edited by the first mechanical and electrical industry agency's review board of Shanghai, Ministry of Japan, and published by mechanical industry, second edition of 12.1985), it is pointed out that for a workpiece with uneven thickness, the thick portion should be immersed into the quenching cooling liquid first, mainly because the thick portion is below when the quenching furnace is charged, so as to prevent the deformation of the product. In addition, although the quenching difference of the thick and thin parts is reduced to a certain extent, the sequence control of the sequential immersion of the thick and thin parts is only insufficient for balancing the surface property difference of the thick and thin parts of workpieces with large thickness and thin difference, such as a planet carrier.
Disclosure of Invention
The invention aims to provide a planet carrier, a casting material and a heat treatment process thereof, which can improve the hardness uniformity of a workpiece with large thickness difference and solve the quality problems of uneven hardness, stress cracking, deformation and the like caused by the wall thickness difference of the product and the high performance requirement of the material.
The invention discloses a heat treatment method of a workpiece, wherein the workpiece comprises a thick part and a thin part, when quenching is carried out, the workpiece is completely immersed into quenching liquid for cooling, after the thin part of the workpiece meets the quenching requirement, the thin part of the workpiece is exposed out of the liquid level, while the thick part of the workpiece is continuously immersed into the liquid for cooling, the workpiece enters a semi-immersion quenching state, after the thick part of the workpiece is quenched, the workpiece integrally leaves the quenching liquid, and the quenching process is finished.
Preferably, the workpiece is a steel casting, the weight percentage of chemical components satisfies, C: less than or equal to 0.25 percent; si: less than or equal to 0.60 percent; mn: 0.50-1.50%; cr: less than or equal to 1.00 percent; ni: less than or equal to 1.00 percent; mo: less than or equal to 1.00 percent; p is less than or equal to 0.035%; s is less than or equal to 0.020%.
Preferably, the steel casting has the chemical composition in percentage by weight as follows: 0.19 to 0.22%, Si: 0.20 to 0.80%, Mn: 0.70-1.20%, Cr: 0.50 to 1.00%, Ni: 0.50 to 1.20%, Mo: 0.20-0.60%, V: 0.03-0.07%; p is less than or equal to 0.025 percent and S is less than or equal to 0.020 percent.
Preferably, the carbon equivalent (Ceq) of the steel casting is controlled to be 0.75-0.82, the hardenability (DI value) is controlled to be 4.2-5.3, and the crack sensitivity index (Pcm) is controlled to be 0.33-0.37.
Preferably, the steel casting is heated to 50-100 ℃ above the Ac3 line and then quenched, and the temperature of the quenching liquid is kept in the range of 25-40 ℃ during quenching.
Preferably, the steel casting is a cylindrical steel casting comprising a thick portion and a thin portion in the axial direction, and the cooling coefficient formula of the thick portion and the thin portion is as follows:
δ＝0.0004φ+0.1
delta represents the quenching cooling coefficient in min/mm, phi represents the maximum effective thermal joint measured and calculated by a thermal joint ball method in mm.
Preferably, the cooling coefficients of the thick portion and the thin portion are calculated according to a cooling coefficient formula, and the quenching cooling time of the thick portion and the thin portion is calculated according to the cooling coefficients, wherein the calculation formula is as follows:
T＝δ×φ
t represents quenching time in min;
according to the calculated quenching cooling time, firstly, completely immersing the whole steel casting into quenching liquid, exposing the thin part of the steel casting out of the quenching liquid for air cooling after the quenching cooling time required by the thin part is finished, continuously immersing the thick part of the steel casting into the quenching liquid, and performing semi-immersion local quenching, wherein the quenching cooling time of the semi-immersion local quenching is calculated as follows:
Tsemi-immersionLiquid for treating urinary tract infection＝TIs thick and thick－TThin sheet
TSemi-immersion liquidDenotes the half-immersion quench cooling time, TIs thick and thickDenotes the quench cooling time, T, of the thick portionThin sheetThe quenching cooling time of the thin portion is shown.
Preferably, after the quenching is finished, the temperature difference Delta T between the thick part and the thin part of the steel casting is less than or equal to 25 ℃.
Preferably, after the steel casting is completely immersed in the quenching liquid, the steel casting moves up and down in the liquid through a lifting device, so that a high-temperature steam film is damaged, and the up-and-down movement of the steel casting is stopped after the surface temperature of the steel casting can be reduced to 380-450 ℃.
Preferably, after the steel casting is quenched and water is discharged, the casting is put into a furnace to be tempered at 590-620 ℃.
The invention also discloses a steel casting which comprises a thick part and a thin part, the chemical components are as described above, the steel casting mechanical property numerical range is as follows by adopting the heat treatment method of the workpiece: stretching at room temperature, Rp0.2740 to 830MPa, Rm865 to 926MPa, A515-20% of the total amount of Z, and 58-66% of the total amount of Z. The low-temperature impact Akv (-40 ℃) (average value) is more than or equal to 50J. The surface hardness test of the workpiece is HB 260-280, the hardness difference is less than or equal to HB20,
preferably, the thin part and the thick part can be rapidly and uniformly cooled in the water quenching process and reach the temperature below the transformation temperature of a bainite structure, the metallographic microstructure obtained after the material is quenched and tempered is bainite, and the grain size is more than or equal to 6.0 grade.
The invention also discloses a planet carrier which is made of the casting material.
The invention has the beneficial effects that: the heat treatment method disclosed by the invention comprises the steps of completely immersing the workpiece into quenching liquid to complete thin part quenching of the workpiece, and continuously immersing and cooling the thick part exposed out of the liquid surface of the thin part until the thick part meets the quenching requirement, so that the thin part and the thick part can reach the optimal quenching time, the hardness uniformity of the workpiece is improved to the maximum extent under the condition that the workpiece reaches high performance, and the quality risks of deformation, cracking and the like are reduced. The heat treatment method can be widely applied to the heat treatment of water quenching, oil quenching and the like of castings, forgings and machined parts with larger thickness difference.
Drawings
FIG. 1 is a perspective view of a wind power planet carrier;
FIG. 2 is a cross-sectional view of a wind power planet carrier;
FIG. 3 is a schematic view of a wind power planet carrier fully immersion cooled;
FIG. 4 is a schematic diagram of partial quenching cooling of half-immersion liquid of a wind power planet carrier;
FIG. 5 is a graph of wall thickness versus water quench cooling time for steel casting materials used in the present invention;
Detailed Description
The present invention is further described below.
After the basic processing of the workpiece is finished, heat treatment can be carried out, quenching treatment is a common heat treatment mode, and the performance of a casting material can be improved by heating the casting to a certain temperature and then cooling the casting at a proper cooling mode and a proper cooling rate. The most important control parameters in the quenching treatment comprise a cooling rate and a final cooling temperature, wherein the cooling rate mainly depends on a cooling mode and a quenching medium, and the quality of the comprehensive mechanical property of the casting is directly influenced by the size of the cooling rate. The control of the final cooling temperature not only determines the type and the amount of the structure transformation products, but also determines the magnitude of stress, and the quality hidden trouble of cracking or deformation of the products can be caused by overlarge stress. For a workpiece with large thickness difference, although the cooling rate can be controlled by controlling the cooling mode and the cooling medium, so that the thin part and the thickness both meet the requirement of the cooling rate, it is difficult to simultaneously take account of the final cooling temperature of the thick part and the thin part, so that the temperature difference of each part after quenching is large, even if the quenching effect is carried out by adopting the mode that the thick part is immersed firstly as indicated in the thermal treatment, the quenching effect is very little, and if the thick part is immersed, the thin part is not immersed into the quenching liquid temporarily, and after the thick part is quenched to a certain degree, the thin part is immersed into the quenching liquid, so that the early stage of the thin part is in an air cooling state, and the cooling curve enters the nose point of the C curve due to slow cooling speed, and the material is subjected to pearlite transformation. The nose point is the corner of the C curve, the inoculation period is shortest, namely, the undercooled austenite is least stable, and non-bainite transformation is easy to occur.
In the heat treatment method of the workpiece, the workpiece also comprises a thick part and a thin part, when quenching, the workpiece is completely immersed into quenching liquid for cooling, after the thin part of the workpiece meets the quenching requirement, the thin part of the workpiece is exposed out of the liquid level, while the thick part of the workpiece is continuously immersed into the liquid for cooling, the workpiece enters a semi-immersion quenching state, after the thick part of the workpiece is quenched, the workpiece is wholly separated from the quenching liquid, and the quenching process is finished. Therefore, the thick part and the thin part can respectively reach respective quenching requirements by respectively controlling the cooling time of the thick part and the thin part, for example, the final cooling temperature of the thick part and the final cooling temperature of the thin part are basically the same, and the quality hidden trouble that the product is cracked or deformed due to stress difference is prevented. The mode that the thick part is downward and the thin part is upward can be adopted, so that the thick part can be firstly immersed in the quenching liquid, and the thin part can be conveniently exposed out of the liquid level to realize semi-immersion quenching.
Taking a certain wind power planet carrier as an example below, the certain wind power planet carrier is a casting, and the weight percentage of chemical components is satisfied, C: less than or equal to 0.25 percent; si: less than or equal to 0.60 percent; mn: 0.50-1.50%; cr: less than or equal to 1.00 percent; ni: less than or equal to 1.00 percent; mo: less than or equal to 1.00 percent; p is less than or equal to 0.035%; s is less than or equal to 0.020%; heating the casting to 50-100 ℃ above the Ac3 line, and quenching after heat preservation. The mechanical property requirement of the wind power planet carrier is met: stretching at room temperature, Rp0.2≥700Mpa，Rm≥830Mpa，A5More than or equal to 12 percent, more than or equal to 30 percent of Z, the surface hardness of the workpiece is HB 240-290, and the hardness difference is less than or equal to HB 30; the low-temperature impact Akv (minus 40 ℃) at minus 40 ℃ is more than or equal to 35J. Wherein R isp0.2、Rm、A5Z is the term in the national standard GB/T228, Rp0.2A yield strength at which the plastic elongation is defined as 0.2%; rmIs tensile strength; a. the5The elongation after the breaking of an original sample with the gauge length of 50mm and the diameter of 10mm is shown; z is the reduction of area. The room temperature test refers to the standard GB/T228.1-2010 part 1 room temperature test method of metal material tensile test, and the hardness test refers to the standard GB/T231.1-2018 part 1 test method of metal material Brinell hardness test.
The invention is carried out on casting materialsFurther optimization is carried out, so that the performance of the material is further improved, and the optimized material comprises 0.19-0.22% of C, 0.20-0.80% of Si, 0.70-1.20% of Mn, 0.50-1.00% of Cr, 0.50-1.20% of Ni, 0.20-0.60% of Mo and 0.03-0.07% of V in percentage by weight; p is less than or equal to 0.025 percent and S is less than or equal to 0.020 percent. On the basis, in order to meet the material performance, individual main elements in the chemical components of the material are reduced and regulated within an allowable range under the conditions of considering the manufacturing cost and combining the existing smelting technology, and the main means is to improve the original strength and the ductility and toughness of the material by matching fine-grained strengthening alloy elements such as manganese, chromium, nickel, molybdenum, vanadium and the like in the material components and controlling the carbon equivalent (Ceq) and the hardenability (DI value) of the material. The cracking risk of the product caused by wall thickness difference is reduced by controlling the crack sensitivity index (Pcm) of the material. Wherein the formula of the carbon equivalent (Ceq) is Ceq ═ C% + Mn%/6 + (Cr% + Cr% + V%)/5 + (Ni% + Cu% +)/15, the higher the value is, the larger the contribution to the strength of the material is, but the repair welding repair of the casting defects is not facilitated; the hardenability (DI value) is represented by the formula DI (mm) ═ 25.4X (C%. times.0.54). times.0 (3.333 XMn% + 1). times.0.7 XSi% + 1). times.2.16 XCr% +1. times. 0.3211+1.4501 XNi% -0.6119 XNi%2+0.1253×Ni％3) Adjusting the DI value to be in a reasonable interval so as to match the comprehensive mechanical property of the product; the crack sensitivity index (Pcm) is expressed as Pcm ═ C% + Si%/30 + (Mn% + Cr% + Cu%)/20 + Ni%/60 + Mo%/15 + V%/10 + B% × 5, and the lower the value of the crack sensitivity index (Pcm), the more advantageous the prevention of the risk of crack generation. This patent carries out corresponding experiment to the composition control scheme in actual production process. Experiments prove that when the carbon equivalent (Ceq) is controlled to be 0.75-0.82, the hardenability (DI value) is controlled to be 4.2-5.3, and the crack sensitivity index (Pcm) is controlled to be 0.33-0.37, the comprehensive mechanical property of the material is favorably improved, particularly the matching of the strength and the ductility and toughness of the material, and the composite material also has a larger effect on preventing the cracking of a product.
During quenching, the casting made of the material is heated to 50-100 ℃ above the Ac3 line and is subjected to heat preservation, and quenching is carried out, wherein the quenching liquid is preferably water or liquid with higher water cooling capacity, so that the cooling rate can meet the requirement. In the embodiment of the patent, 900 +/-10 ℃ is adopted as the quenching temperature.
And after determining the heating and heat-preserving temperature and the quenching liquid, carrying out the research on quenching and cooling parameters. As shown in fig. 5, which is a graph of wall thickness of the wind power planet carrier and water quenching cooling time, according to the graph, the cooling coefficient formula of the wind power planet carrier is δ being 0.0004 Φ +0.1, δ represents the quenching cooling coefficient in units of min/mm, and Φ represents the maximum effective thermal joint measured by the thermal joint sphericity method in units of mm. The curve chart can be used for determining the cooling coefficient of the wind power planet carrier and can also be used in other cylindrical castings which are made of the same materials as the wind power planet carrier and have similar structures.
The cooling coefficients of the thick part and the thin part are respectively calculated according to a cooling coefficient formula, and the quenching cooling time of the thick part and the thin part is respectively calculated according to the cooling coefficients, wherein the calculation formula is as follows: t is δ × Φ, T represents the quenching time in min; according to the calculated quenching cooling time, firstly, completely immersing the whole casting into quenching liquid, exposing the thin part of the casting out of the quenching liquid for air cooling after the quenching cooling time required by the thin part is finished, continuously immersing the thick part of the casting into the quenching liquid, and performing semi-immersion local quenching, wherein the quenching cooling time of the semi-immersion local quenching is calculated as follows: t isSemi-immersion liquid＝TIs thick and thick－TThin sheet，TSemi-immersion liquidDenotes the half-immersion quench cooling time, TIs thick and thickDenotes the quench cooling time, T, of the thick portionThin sheetThe quenching cooling time of the thin portion is shown.
In this embodiment, as shown in fig. 1 and 2, the wind power planet carrier casting comprises a thick portion and a thin portion and is distributed up and down, and the maximum effective thermal joint phi of the wall thickness of the thick portion of the planet carrier casting is respectively measured and calculated by using a thermal joint sphere methodIs thick and thick350mm, maximum effective thermal budget phi of thin wall thicknessThin sheetIs 200 mm. The quenching time coefficient delta of the thick part of the planet carrier casting can be calculated according to a cooling coefficient formulaIs thick and thick24 minutes/100 mm, thin portion quenching time coefficient deltaThin sheet18 minutes/100 mm, minimum water quench cooling time T required for the thick portion to ensure that below the tissue transition temperature and complete the tissue transitionIs thick and thick84 minutes, the shortest water quenching cooling time T required for the thin partThin sheetQuenching in full immersion liquid for 36 minutesThe cooling time is 36 minutes, and the half-immersion quenching cooling time TSemi-immersion liquidWas 48 minutes. Therefore, according to the calculated quench cooling time, as shown in fig. 3, the entire casting is first completely immersed in water, and the water quench cooling time T required for completing the thin portion is performedThin sheetAfter 36 minutes, the thin portion (upper end) of the casting was exposed to the water for air cooling, while the thick portion (lower end) of the casting was continuously submerged in water, and semi-submerged partial quenching T was performedSemi-submerged waterAfter 48 minutes.
During quenching, the water tank keeps a circulating and mechanical stirring state, and the water temperature is kept within the range of 25-40 ℃ so as to ensure the quenching effect. After entering water, water on the external surface layer of the casting is immediately heated and vaporized to form a high-temperature steam film to isolate heat transfer, so that the cooling rate of the casting is extremely low. In order to destroy the steam film, after the casting is completely immersed in the quenching liquid, the casting is moved up and down in the liquid through the hoisting equipment, so that the high-temperature steam film is destroyed, and the up-and-down movement of the casting is stopped after the surface temperature of the casting is reduced to 380-450 ℃. In the embodiment, the whole moving process is about 5 minutes, so that the surface of the casting can be ensured not to generate a high-temperature steam film, the heat transfer stage of the steam film is finished, and the casting enters the boiling heat transfer stage for cooling. And (4) sequentially executing the full immersion quenching cooling time and the half immersion quenching cooling time, discharging water from the whole casting, and finishing the quenching process.
After the product is quenched and water is discharged, the casting is put into a furnace to be tempered at 590-620 ℃, and part of carbides in a saturated bainite structure can be separated out in the tempering process, so that the hardness of the material is further enhanced, the bainite structure can be softened, internal stress is released, and the risk of cracking and deformation of the casting is further reduced.
After the planet carrier is quenched, the temperature difference delta T between the thick part and the thin part of the casting is less than or equal to 25 ℃, and the product has no crack and no deformation. After tempering, the hardness difference between the thick part and the thin part is less than or equal to 20 HB. After the batch castings are quenched by adopting the method, the thin parts and the thick parts can be rapidly and uniformly cooled in the water quenching process and reach the temperature below the transformation temperature of a bainite structure, the metallographic microstructure obtained after material quenching and tempering is bainite, and the grain size is more than or equal to 6.0 grade.
In addition, before finally determining the chemical components and the heat treatment mode of the wind power planet carrier, the applicant carries out a specific test on a casting material, the molten steel is smelted for 20 times according to the following specified component requirements, the specific components are shown in table 1, then sand mold casting molding is adopted, the casting is subjected to heat treatment after boxing and sand shakeout, the heat treatment process is that the casting is heated to 900 +/-10 ℃ and then is quenched, and the mechanical property detection is carried out after tempering at 590-620 ℃, and the result is shown in table 2. The test material for mechanical property test is a casting test block, and the length, width and height of the test block are as follows: 220 x 120 x 70mm, and the test block is molded along with the casting, poured in the same furnace and thermally treated in the same furnace.
Table 1: list of cast product ingredients
Figure BDA0002789197550000061
Figure BDA0002789197550000071
Table 2: mechanical property data of casting
Figure BDA0002789197550000072
Through the tests, the applicant finally confirms that the chemical components of the material of the wind-out electricity planet carrier are 0.19-0.22% of C, 0.20-0.80% of Si, 0.70-1.20% of Mn, 0.50-1.00% of Cr, 0.50-1.20% of Ni, 0.20-0.60% of Mo and 0.03-0.07% of V; p is less than or equal to 0.025 percent, S is less than or equal to 0.020 percent, and the mechanical property numerical range is as follows: stretching at room temperature, Rp0.2740 to 830MPa, Rm865 to 926MPa, A515-20% of the total amount of Z, and 58-66% of the total amount of Z. The low-temperature impact Akv (-40 ℃) (average value) is more than or equal to 50J. The surface hardness test of the workpiece is HB 260-280, and the hardness difference is less than or equal to HB 20.

Claims (13)

1. A heat treatment method of a workpiece, the workpiece comprises a thick part and a thin part, and is characterized in that during quenching, the workpiece is completely immersed into quenching liquid for cooling, after the thin part of the workpiece reaches the quenching requirement, the thin part of the workpiece is exposed out of the liquid level, the thick part of the workpiece is continuously immersed into the liquid for cooling, the workpiece enters a half-immersion quenching state, after the thick part of the workpiece is quenched, the whole workpiece leaves the quenching liquid, and the quenching process is finished.
2. A method of heat treating a workpiece according to claim 1, characterized by: the workpiece is a steel casting, the weight percentage of chemical components meets, C: less than or equal to 0.25 percent; si: less than or equal to 0.60 percent; mn: 0.50-1.50%; cr: less than or equal to 1.00 percent; ni: less than or equal to 1.00 percent; mo: less than or equal to 1.00 percent; p is less than or equal to 0.035%; s is less than or equal to 0.020%.
3. A heat treatment method for a workpiece as defined in claim 2, characterized in that: the steel casting comprises the following chemical components in percentage by weight: 0.19 to 0.22%, Si: 0.20 to 0.80%, Mn: 0.70-1.20%, Cr: 0.50 to 1.00%, Ni: 0.50 to 1.20%, Mo: 0.20-0.60%, V: 0.03-0.07%; p is less than or equal to 0.025 percent and S is less than or equal to 0.020 percent.
4. A method for heat-treating a workpiece as defined in claim 2 or 3, characterized by: the carbon equivalent of the steel casting is controlled to be 0.75-0.82, the hardenability is controlled to be 4.2-5.3, and the crack sensitivity index is controlled to be 0.33-0.37.
5. The heat treatment method of a workpiece as set forth in claim 2, 3 or 4, characterized in that: and heating the steel casting to 50-100 ℃ above the Ac3 line, and then quenching the steel casting after heat preservation, wherein the temperature of a quenching liquid is kept in the range of 25-40 ℃ during quenching.
6. The heat treatment method of a workpiece as set forth in any one of claims 2 to 5, characterized in that: the steel casting is a cylindrical steel casting comprising a thick part and a thin part in the axial direction, and the cooling coefficient formulas of the thick part and the thin part are as follows:
δ＝0.0004φ+0.1
delta represents the quenching cooling coefficient in min/mm, phi represents the maximum effective thermal joint measured and calculated by a thermal joint ball method in mm.
7. The heat treatment method of a workpiece according to claim 6, characterized in that: the cooling coefficients of the thick part and the thin part are respectively calculated according to a cooling coefficient formula, and the quenching cooling time of the thick part and the thin part is respectively calculated according to the cooling coefficients, wherein the calculation formula is as follows:
T＝δ×φ
t represents quenching time in min;
according to the calculated quenching cooling time, firstly, completely immersing the whole steel casting into quenching liquid, exposing the thin part of the steel casting out of the quenching liquid for air cooling after the quenching cooling time required by the thin part is finished, continuously immersing the thick part of the steel casting into the quenching liquid, and performing semi-immersion local quenching, wherein the quenching cooling time of the semi-immersion local quenching is calculated as follows:
Tsemi-immersion liquid＝TIs thick and thick－TThin sheet
TSemi-immersion liquidDenotes the half-immersion quench cooling time, TIs thick and thickDenotes the quench cooling time, T, of the thick portionThin sheetThe quenching cooling time of the thin portion is shown.
8. The heat treatment method of a workpiece according to claim 7, characterized in that: after the quenching is finished, the temperature difference delta T between the thick part and the thin part of the steel casting is less than or equal to 25 ℃.
9. A method for heat-treating a workpiece as defined in any one of claims 2 or 3, characterized by: after the steel casting is completely immersed in the quenching liquid, the steel casting moves up and down in the liquid through the hoisting equipment, so that the high-temperature steam film is damaged, and the up-and-down movement of the steel casting is stopped after the surface temperature of the steel casting can be reduced to 380-450 ℃.
10. A method for heat-treating a workpiece as defined in claim 2 or 3, characterized by: and after the quenching of the steel castings is finished and water is discharged, the castings are put into a furnace to be tempered at 590-620 ℃.
11. A cast material comprising thick portions and thin portions, characterized in that the chemical composition is as defined in any one of claims 2 to 10, and the mechanical properties of the cast steel are within the following ranges by the heat treatment method of the workpiece as defined in any one of claims 1 to 10: stretching at room temperature, Rp0.2740 to 830MPa, Rm865 to 926MPa, A515-20% of the total amount of Z, and 58-66% of the total amount of Z. The low-temperature impact Akv (-40 ℃) (average value) is more than or equal to 50J. The surface hardness test of the workpiece is HB 260-280, and the hardness difference is less than or equal to HB 20.
12. The casting material of claim 11, wherein: the thin part and the thick part can be rapidly and uniformly cooled in the water quenching process and reach the temperature below the transformation temperature of a bainite structure, the metallographic microstructure obtained after the material is quenched and tempered is bainite, and the grain size is more than or equal to 6.0 grade.
13. A planet carrier, characterised in that the cast material according to any of claims 11-12 is used.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117512429A (en) * 2024-01-05 2024-02-06 上海开维喜阀门有限公司 LC1 valve casting method

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1401792A (en) * 2002-09-05 2003-03-12 上海交通大学 Large alloy steel member water quenching layer built self-tempering process
CN102517432A (en) * 2012-01-20 2012-06-27 南京汽车锻造有限公司 Quenching method for front shell of differential
CN102965588A (en) * 2012-11-29 2013-03-13 南车戚墅堰机车车辆工艺研究所有限公司 Low-alloy high-strength cast steel, and smelting and heat treatment method thereof
CN104482180A (en) * 2014-09-15 2015-04-01 宝鼎重工股份有限公司 Planet carrier casting material used for self-elevating offshore platform lifting gear box and production method
CN107447090A (en) * 2017-08-01 2017-12-08 清华大学 Nonuniform workpiece equilibrium heat-treating methods
CN107447083A (en) * 2017-01-19 2017-12-08 天津万立鑫晟新材料技术研究院有限公司 Application method of the PAG water-based hardening liquids in rich chromium cast iron heat treating castings
CN108588349A (en) * 2018-06-29 2018-09-28 上海建桥学院 A kind of impewdance matching compensation device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1401792A (en) * 2002-09-05 2003-03-12 上海交通大学 Large alloy steel member water quenching layer built self-tempering process
CN102517432A (en) * 2012-01-20 2012-06-27 南京汽车锻造有限公司 Quenching method for front shell of differential
CN102965588A (en) * 2012-11-29 2013-03-13 南车戚墅堰机车车辆工艺研究所有限公司 Low-alloy high-strength cast steel, and smelting and heat treatment method thereof
CN104482180A (en) * 2014-09-15 2015-04-01 宝鼎重工股份有限公司 Planet carrier casting material used for self-elevating offshore platform lifting gear box and production method
CN107447083A (en) * 2017-01-19 2017-12-08 天津万立鑫晟新材料技术研究院有限公司 Application method of the PAG water-based hardening liquids in rich chromium cast iron heat treating castings
CN107447090A (en) * 2017-08-01 2017-12-08 清华大学 Nonuniform workpiece equilibrium heat-treating methods
CN108588349A (en) * 2018-06-29 2018-09-28 上海建桥学院 A kind of impewdance matching compensation device

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
张国栋: "45Cr2NiMoVSi钢制锤锻模的热处理", 《金属热处理》 *
张玉庭: "锻模淬火一次提尾自回火工艺参数的确定", 《模具工业》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117512429A (en) * 2024-01-05 2024-02-06 上海开维喜阀门有限公司 LC1 valve casting method
CN117512429B (en) * 2024-01-05 2024-03-15 上海开维喜阀门有限公司 LC1 valve casting method

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