CN114570889A - Casting process of rocker arm shell of ultra-thick coal seam mining machine - Google Patents
Casting process of rocker arm shell of ultra-thick coal seam mining machine Download PDFInfo
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- CN114570889A CN114570889A CN202210175838.9A CN202210175838A CN114570889A CN 114570889 A CN114570889 A CN 114570889A CN 202210175838 A CN202210175838 A CN 202210175838A CN 114570889 A CN114570889 A CN 114570889A
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- 238000005266 casting Methods 0.000 title claims abstract description 117
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- 238000005065 mining Methods 0.000 title claims abstract description 53
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- 239000011347 resin Substances 0.000 claims abstract description 7
- 229920005989 resin Polymers 0.000 claims abstract description 7
- 238000000465 moulding Methods 0.000 claims abstract description 6
- 239000000919 ceramic Substances 0.000 claims abstract description 5
- 244000035744 Hura crepitans Species 0.000 claims abstract description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 26
- 239000010959 steel Substances 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 20
- 239000011248 coating agent Substances 0.000 claims description 10
- 238000000576 coating method Methods 0.000 claims description 10
- 238000005520 cutting process Methods 0.000 claims description 8
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- 239000004927 clay Substances 0.000 claims description 5
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- 238000010438 heat treatment Methods 0.000 claims description 4
- 230000004048 modification Effects 0.000 claims description 4
- 238000012986 modification Methods 0.000 claims description 4
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 4
- 150000002910 rare earth metals Chemical class 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010703 silicon Substances 0.000 claims description 4
- 238000009628 steelmaking Methods 0.000 claims description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 238000010079 rubber tapping Methods 0.000 claims description 3
- 229910052845 zircon Inorganic materials 0.000 claims description 3
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 claims description 3
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/22—Moulds for peculiarly-shaped castings
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/02—Sand moulds or like moulds for shaped castings
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
- B22C9/082—Sprues, pouring cups
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
- B22C9/088—Feeder heads
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
The invention relates to a casting process of a rocker arm shell of a coal mining machine for an extra-thick coal seam, which takes the plane passing through the axis of a motor cylinder of the rocker arm shell of the coal mining machine and the axis of a planet head mounting cylinder as a parting surface, adopts a sand box molding casting mode combining a real mould and a core assembly, a sand mould outer mould and a loam core are made of resin sand, a casting water channel part, a round corner part and a corner part on the loam core are made of chromite sand, an open bottom return type pouring system is adopted, a horizontal pouring mode is adopted, the pouring system is all made of ceramic tubes, the planet head mounting cylinder and the motor cylinder are respectively provided with an open riser, the joint of the motor cylinder and the arm support is provided with an open riser, four blind risers are arranged on the upper plane of the arm support and at intervals on the edge close to the coal wall side, two blind risers are arranged on the upper plane of the arm support and at intervals on the edge close to the mining side, and a plurality of external chills are arranged at the bottom of the lower box. The invention can avoid many casting defects, shorten the production period and improve the casting quality and the production efficiency.
Description
Technical Field
The invention relates to a novel process for casting a rocker arm shell of a super-thick coal seam mining machine.
Background
The rocker arm shell of the super-thick coal seam mining machine is a large box type steel casting, casting defects such as shrinkage, looseness, cracks, air holes, sand inclusion, sand adhesion and the like are easily generated according to the conventional casting process, the defects are mainly caused by the fact that the shell is complex in structure, a plurality of hot spots are arranged, the compactness of molding sand is uneven, the cleaning of floating sand in a cavity is incomplete when a core is placed, a mud core of a motor cylinder floats upwards, and the like, the defects directly cause the necessary patching treatment on the defect part in the subsequent machining process, great difficulty is brought to the subsequent machining, the production organization of a product is seriously influenced, and therefore, a large amount of manpower, material resources and financial resources are required to be input. On the other hand, when the rocker arm shell of the coal mining machine is used, a plurality of transmission systems need to be installed inside the rocker arm shell, the mechanical performance of the transmission shell cannot meet the use requirement due to the existence of casting defects, the shell is deformed and the hole system is abraded and deformed in the use process, and even the rocker arm shell generates leakage phenomenon and other accidents which influence production in the use process.
Disclosure of Invention
The invention aims to provide a casting process of a rocker arm shell of a super-thick coal seam mining machine, which can avoid a plurality of casting defects, shorten the production period, improve the casting quality and the production efficiency of the rocker arm shell and reduce the labor intensity of workers.
The main technical scheme of the invention is as follows:
a casting process of a rocker arm shell of a coal mining machine for an extra-thick coal seam is characterized in that ZG25MnNi material is adopted for casting, a plane passing through the motor cylinder axis and the planet head installation cylinder axis of the rocker arm shell of the coal mining machine is taken as a parting surface, a sand box molding casting mode combining a sample mold and a core assembly is adopted, a sand mold outer mold and a clay core are manufactured by resin sand, chromite sand is adopted at a casting water channel part, a round corner part and a corner part on the clay core, 40-80-mesh sea sand is adopted at the rest part of a sand mold, alcohol-based zircon powder coating is adopted as the coating, an open bottom-return type pouring system is adopted and a horizontal pouring mode is adopted, the pouring system is all manufactured by ceramic tubes, a first dead head and a second dead head are respectively arranged above the planet head installation cylinder and the motor cylinder, a third dead head is arranged at the triangular connection part of the motor cylinder and an arm support, fourth dead heads, third dead heads, fourth dead heads, third dead heads, are sequentially arranged at intervals, on the upper plane of the arm support, and the edge close to the side of the coal wall side, are arranged at intervals, and the starting point of the lower speed end of the arm support, and the lower end of the upper plane of the support, and the upper plane of the support is taken as the support The fourth blind riser and the fifth blind riser are positioned on the mining side of the planet head mounting cylinder, the seventh blind riser and the eighth blind riser are respectively arranged on the upper plane of the arm support and the low-speed end part and the middle part of the arm support close to the edge of the mining side, the ninth blind riser is arranged on the upper plane of the arm support and the four-axis to seven-axis positions of the coal wall side, the first group of external chillers are arranged on the plane of the lower box of the motor cylinder and the triangular joint part of the lower part of the motor cylinder and the arm support, the second group of external chillers are arranged on the end surface of one axis, the third group of external chillers are arranged on the coal wall side and the edge of the mining side along the water channel at the bottom of the arm support, and the fourth group of conformal external chillers are arranged at the bottom of the lower box of the planet head mounting cylinder.
The fourth blind riser and the fifth blind riser are heating risers, the rest risers are heat-insulating risers, and the first open riser and the second open riser are wooden risers.
The first open riser and the second open riser are cuboid risers, the sixth blind riser, the seventh blind riser and the eighth blind riser are long cylindrical risers, the rest risers are cylindrical risers, and the blind risers are spherical-top cylindrical risers.
The first and second open risers are 850mm multiplied by 500mm multiplied by 750mm, the third open riser is 400mm multiplied by 750mm, the fourth and fifth dark risers are 320mm multiplied by 415mm, and the sixth, seventh, eighth and ninth dark risers are 280mm multiplied by 420mm multiplied by 365mm, 220mm multiplied by 330mm multiplied by 285mm, 260mm multiplied by 390mm multiplied by 340mm and 260mm multiplied by 310mm in sequence.
The lengths of the core print on the coal wall side and the mining side of the planet head installation barrel are respectively 350mm and 300mm, the lengths of the core print on the coal wall side of one shaft and the core print on the coal wall side of the other shaft are both 250mm, the lengths of the core prints on the four shafts to the seven shafts on the coal wall side are 550mm, the length of the core print on the hole position of the motor barrel is 250mm, and the length of the core print corresponding to the large plane on the mining side of the arm support is 400 mm.
The size of the first group of external chilling blocks is 220mm multiplied by 100mm, the number of the first group of external chilling blocks is 30-40 blocks, the size of the second group of external chilling blocks is 200mm multiplied by 100mm, the number of the second group of external chilling blocks is 4-6 blocks, the size of the third group of external chilling blocks is 200mm multiplied by 100mm, the number of the third group of external chilling blocks is 15-25 blocks, the size of the fourth group of conformal external chilling blocks is 400mm multiplied by 200mm multiplied by 100mm, and the number of the fourth group of conformal external chilling blocks is 3-5 blocks.
The number of the first to fourth groups of external chills is further preferably 40, 4, 20 and 3 in this order.
Preferably, an external chill is arranged at the position of a fillet connected with the root part of the motor barrel at the three shafts of the inner cavity of the arm support.
One straight pouring channel with the diameter of 120mm is adopted in the pouring system, two transverse pouring channels with the diameter of 100mm are adopted and are separated from the middle to two sides, and two inner pouring channels with the diameter of 100mm are adopted in the inner pouring channel.
After demolding, normalizing the casting with a casting head at 910 +/-10 ℃ for 8-10 hours, hot cutting and hot planing the casting head at the temperature of more than 250 ℃ after normalizing, carrying out carbon planing on the flash, burr and the root of the non-machined part of the casting after hot cutting of the casting head, and tempering at 650 ℃ for 6-8 hours after carbon planing.
Deoxidizing before the furnace is carried out in the steel making process, adopting rare earth silicon to carry out modification treatment in a steel ladle, controlling the tapping temperature at 1580-.
The pouring temperature is preferably controlled at 1520 and 1560 ℃, slow pouring is carried out firstly, then fast pouring with large flow is carried out, and finally slow pouring is carried out, after the pouring is completed, the pouring is stopped for 15 minutes, and then the pouring is stopped for 5 minutes, and the pouring is carried out once.
The invention has the beneficial effects that:
the plane of the motor cylinder axis and the planet head mounting cylinder axis of the rocker arm shell of the coal mining machine is set as a parting surface, so that the sequential solidification mode from a casting to a riser is better ensured, the casting defects of looseness, shrinkage cavity and the like of the thick part of the shell are favorably prevented, the density of the casting is improved, and the leakage phenomenon of the casting in the using process is prevented.
The sand mold outer mold and the sand core are made of resin sand, the casting water channel part, the fillet part and the corner on the sand core are made of chromite sand, so that the corresponding sand mold is guaranteed to have enough compactness and surface finish, the shrinkage rate of the casting can be increased by utilizing the characteristic of better deformability of the resin sand casting mold, and the shrinkage rate of the casting, which is reduced due to the complex structure and difficult shrinkage, is compensated.
The quality of castings of the rocker arm shell of the super-thick coal seam mining machine can be improved from the following aspects by adopting the open bottom-return type pouring system: (1) the molten steel is stably filled, so that serious turbulence is avoided, and entrainment, gas absorption and transition oxidation of the molten steel are prevented, thereby obtaining better internal quality of the casting; (2) the molten steel can be prevented from entering the cavity at an excessively high speed, and the molten steel is prevented from splashing and scouring the wall of the cavity or the surface of the sand core, so that the phenomena of sand inclusion and sand washing are avoided; (3) the rising speed of the molten steel is higher than that of a top injection type pouring system and a middle injection type pouring system, so that the gas in the cavity can be discharged, and the defect of air holes in the casting can be reduced; (4) can prevent the insufficient casting of the casting and the cold shut line on the surface.
Adopt horizontal pouring mode to replace traditional vertical pouring mode, not only can effectively reduce the die joint, reduce the sand mould height to reduce the molding and pouring operation degree of difficulty, more importantly combines the selection of above-mentioned die joint, still is favorable to the setting of rising head very much, can improve the feeding efficiency of rising head, realizes the sequential solidification, is favorable to the feeding of the thick major part of foundry goods very much, can eliminate shrinkage cavity, loose, guarantees to obtain compact foundry goods.
The gating system is made of ceramic tubes, so that sand washing is prevented, and the sand sticking phenomenon caused by the gates is avoided.
The planet head mounting cylinder and the motor cylinder are respectively provided with an open riser, a third open riser is arranged at the triangular connection position of the motor cylinder and the arm support, a fourth blind riser, a fifth blind riser and a sixth blind riser are sequentially arranged at intervals on the upper plane of the arm support and the edge close to the coal wall side by taking the low-speed end of the arm support as a starting point, a seventh blind riser and an eighth blind riser are respectively arranged on the upper plane of the arm support and the low-speed end part and the middle part of the arm support close to the edge of the mining side, and a ninth blind riser is arranged on the upper plane of the arm support and the four-axis to seven-axis positions of the coal wall side, so that the defects of shrinkage cavity and looseness at the root part of the risers, namely the top of the shell can be well eliminated.
The first group of external chills are arranged on the plane of the lower box of the motor cylinder and at the triangular joint of the lower part of the motor cylinder and the arm support, the second group of external chills are arranged on the end surface of a shaft, the third group of external chills are arranged on the coal wall side and the edge of the mining side along the water channel at the bottom of the arm support, and the fourth group of conformal external chills are arranged at the bottom of the lower box of the planet head mounting cylinder, so that the feeding distance of a dead head can be increased, the shrinkage cavity and loosening defects at the bottom of the shell are eliminated, the crack defects at the crossed part and the sharply changed part of the wall thickness at the bottom of the shell are prevented, the sequential solidification condition of the casting is enhanced, and the local metallographic structure and the mechanical property of the casting are improved. Through the combination of the dead head and the external chill, the defects of complete shrinkage cavity and looseness in the shell are eliminated, and the internal quality of the casting is greatly improved.
The pre-furnace deoxidation is preferably carried out in the steel-making process, rare earth silicon is adopted in a steel ladle for modification treatment and a steel ladle bottom argon blowing technology, so that the contents of gas and harmful elements in the molten steel are reduced, and the purity of the molten steel is strictly controlled.
The pouring temperature is preferably controlled at 1520 and 1560 ℃, slow pouring is carried out firstly, then fast pouring with large flow is carried out, and finally slow pouring is carried out, after the pouring is completed, the pouring is stopped for 15 minutes, and then the pouring is stopped for 5 minutes, and the pouring is carried out once. By controlling the pouring temperature and the pouring speed, the feeding capacity of the molten steel can be increased, and the compact structure of the casting is ensured.
The casting technology of the invention improves the casting technology of the rocker arm shell casting of the ultra-thick coal seam mining machine, further improves the casting quality, improves the casting density, eliminates the casting defects of shrinkage cavity, looseness, cracks and the like in different degrees at the middle part of the rocker arm shell where the root of the motor cylinder is connected with the three shafts, the thick part of the connecting surface of the transition frame on the rocker arm shell, the inner part of the planet head mounting cylinder and the like, and successfully solves the problem of oil leakage caused by the casting defects of the shell.
Drawings
FIG. 1 is a perspective view of a 3050 shearer ranging arm casing;
FIG. 2 is a horizontal cross-sectional view of a 3050 shearer loader rocker arm housing;
FIG. 3 is a front view of a 3050 shearer ranging arm casing;
FIG. 4 is a schematic view of riser placement;
FIG. 5 is a first schematic diagram of the arrangement of external chillers;
fig. 6 is a schematic diagram of the arrangement of the external chiller.
Description of the drawings: 1.3050 shearer rocker arm shell casting; 1-1. motor cylinder; 1-2, arm support; 1-3, a planet head mounting cylinder; 2-1, a first open riser; 2-2, a second open riser; 2-3, a third open riser; 2-4, a fourth blind riser; 2-5, a fifth blind riser; 2-6, a sixth blind riser; 2-7, a seventh blind riser; 2-8, an eighth blind riser; 2-9. ninth blind riser; 3. a pouring system; 4-1. a first group of external chills; 4-2. a second set of external chills; 4-3. a third group of external chills; 4-4. a fourth group of conformal external chilling blocks; 4-5, external chilling iron.
Detailed Description
The invention discloses a novel casting process of a rocker arm shell (which can be referred to as a rocker arm shell for short and has a structure shown in figures 1-3) of an ultra-thick coal seam mining machine, which can eliminate the casting defects of shrinkage cavities, looseness, cracks, air holes, sand inclusion, bonded sand and the like which are easily caused by the rocker arm shell casting 1 of the ultra-thick coal seam mining machine obtained by adopting the original casting process, obtain the rocker arm shell casting with compact structure and higher surface quality, greatly reduce the workload of subsequent machining, shorten the production period, reduce the labor intensity of workers, save the production cost and facilitate the production of the structure. In this embodiment, a casting process of the present invention is described by taking a 3050 shearer ranging arm casing as an example. 3050 the transmission system to be installed in the rocker arm shell of the coal mining machine totally relates to nine transmission shafts, which are sequentially arranged from one end to the other end of the rocker arm shell in the length direction from one shaft to nine shafts, wherein one shaft is coaxial with the motor barrel 1-1, the nine shafts are coaxial with the planetary head installation barrel 1-3, correspondingly, shaft holes of one shaft to the nine shafts are formed in the rocker arm shell of the 3050 coal mining machine, and the shaft holes of the two shafts are not shown. In practice, the two-axis shaft holes may not be cast. For the sake of description, hereinafter, the "several axes" means "several axes holes".
The casting process mainly comprises the following key contents:
1. the casting material adopts ZG25 MnNi. The comprehensive mechanical property comparison is carried out on a test bar made of corresponding materials after the test bar is subjected to normalizing and quenching and tempering heat treatment, and the ZG25MnNi is used for replacing the original material ZG30 CrNiMo.
2. The modeling mode is as follows: the plane of the axis of the motor barrel 1-1 and the axis of the planet head mounting barrel 1-3 of the rocker arm shell of the coal mining machine is taken as a parting surface, so that the sequential solidification mode from a casting to a riser can be better ensured, the casting defects of looseness, shrinkage cavity and the like of the thick part of the shell can be favorably prevented, the density of the casting is improved, and the leakage phenomenon of the casting in the using process is prevented. The sand box molding casting mode combining the solid mold and the core assembly is adopted, and the characteristics of complex casting structure, small batch, high appearance and internal quality requirements of the rocker arm shell of the 3050-like super-thick coal seam mining machine are better met. The wood pattern is preferably a template pattern, and the template is provided with a positioning pin so as to facilitate and accurately close the box.
3. Casting mold material: the sand mold outer mold and the sand core are made of resin sand, the casting water channel part, the round corner part and the corner part on the sand core are made of chromite sand, the thickness of the chromite sand layer is preferably 10-20mm, and sufficient compactness and surface smoothness are guaranteed. The rest parts of the sand mould are made of 40-80 mesh sea sand. The resin sand casting mold has good deformability, and can increase the shrinkage rate of the casting and compensate for the shrinkage rate of the casting which is reduced due to the complex structure and difficult shrinkage.
4. Coating: the coating is alcohol-based zircon powder coating. And baking the sand core by using a spray gun after the sand core is manufactured, and coating the paint on the surface for three times after baking. And (4) coating the surface of the sand mold with the coating for four times after drying.
5. Designing a pouring system: an open bottom-return gating system 3 is adopted and a horizontal pouring mode is adopted. The quality of castings of the 3050 coal mining machine rocker arm shell can be improved by adopting the open bottom-return gating system from the following aspects: (1) the molten steel is stably filled, so that serious turbulence is avoided, and entrainment, gas absorption and transition oxidation of the molten steel are prevented, thereby obtaining better internal quality of the casting; (2) the molten steel can be prevented from entering the cavity at an excessively high speed, and the molten steel is prevented from splashing and scouring the wall of the cavity or the surface of the sand core, so that the phenomena of sand inclusion and sand washing are avoided; (3) the rising speed of the molten steel is higher than that of a top injection type pouring system and a middle injection type pouring system, so that the gas in the cavity can be discharged, and the defect of air holes in the casting can be reduced; (4) can prevent the insufficient casting of the casting and the cold shut line on the surface.
Adopt horizontal pouring mode to replace traditional vertical pouring mode, not only can effectively reduce the die joint, reduce the sand mould height to reduce the molding and pouring operation degree of difficulty, more importantly combines the selection of above-mentioned die joint, still is favorable to the setting of rising head very much, can improve the feeding efficiency of rising head, realizes the sequential solidification, is favorable to the feeding of the thick major part of foundry goods very much, can eliminate shrinkage cavity, loose, guarantees to obtain compact foundry goods.
The gating system is made of ceramic tubes, so that sand washing is prevented, and the sand sticking phenomenon caused by the gates is avoided.
6. And (3) riser design: as shown in fig. 4, a first dead head 2-1 and a second dead head 2-2 are respectively arranged above the planet head mounting cylinder and the motor cylinder, a third dead head 2-3 is arranged at the triangular joint of the upper part of the motor cylinder and the arm support 1-2 (which refers to the part of the arm support shell except the motor cylinder), a fourth dead head 2-4, a fifth dead head 2-5 and a sixth dead head 2-6 are sequentially arranged at intervals on the upper plane of the arm support and the edge close to the coal wall side by taking the low-speed end of the arm support (which refers to the end of the arm support close to the planet head mounting cylinder) as a starting point, the fifth dead head mainly performs feeding on the middle part of a seven shaft and an eight shaft, the sixth dead head mainly performs feeding on the middle part of a four shaft and a five shaft, wherein the fourth dead head and the fifth dead head are arranged on the mining side of the planet head mounting cylinder, and the low-speed end part and the middle part of the arm support and the edge close to the mining side are respectively provided with a seventh dead head 2-7 and an eighth dead head 2-2 And 2-8 risers, wherein the eighth blind riser mainly performs feeding on the middle parts of five shafts and six shafts, the ninth blind riser 2-9 is arranged on the upper plane of the arm support and on the positions from four shafts to seven shafts on the coal wall side, and the ninth blind riser mainly performs feeding on the middle parts of five shafts and six shafts. All risers are top risers. The arrangement of the risers can well eliminate the defects of shrinkage cavity and looseness at the root parts of the risers, namely the tops of the shells. The third open riser can simultaneously feed two shafts and three shafts, even middle parts of one shaft and three shafts and middle parts of three shafts and four shafts. Each riser corresponds to a feeding area, and the modulus of the riser can be determined according to the size of a thermal node of a feeding part of the riser. The preliminary division of the feeding area can be determined by carrying out thermal section analysis on the castings of the corresponding rocker arm shells of the coal mining machines by utilizing computer simulation software.
7. Designing a cold iron: as shown in figure 5, a first group of external chillers 4-1 are arranged on the plane of a lower box of the motor cylinder and at the triangular joint of the lower part of the motor cylinder and the arm support, a second group of external chillers 4-2 are arranged on the end surface of a shaft, a third group of external chillers 4-3 are arranged on the coal wall side and the mining side edge along the water channel at the bottom of the arm support, and a fourth group of conformal external chillers 4-4 are arranged at the bottom of the lower box of the planet head mounting cylinder. By arranging the external chill, the feeding distance of the riser can be increased, the defects of shrinkage cavities and looseness of parts (such as the bottom of a rocker arm shell) which are difficult to feed the riser are eliminated, the defects of cracks at the crossed parts of the wall thickness of the bottom of the shell and the parts with rapid changes are prevented, the sequential solidification condition of a casting is enhanced, and the local metallographic structure and the mechanical property of the casting are improved. Through the combination of the dead head and the external chill, the defects of complete shrinkage cavity and looseness in the shell are eliminated, and the internal quality of the casting is greatly improved.
Regarding the risers, the fourth and fifth blind risers preferably adopt exothermic risers, the rest risers adopt heat-insulating risers, and the first and second open risers are wooden risers, so that the root of the planet head mounting cylinder is finally solidified, and higher tissue density and mechanical strength are obtained. The vent hole with the diameter of 30mm is arranged at the top of the blind riser.
Furthermore, the first open riser and the second open riser adopt cuboid risers, the sixth blind riser, the seventh blind riser and the eighth blind riser adopt long cylindrical risers, and the rest risers adopt cylindrical risers, wherein the blind risers are all spherical-top cylindrical risers. By adopting the riser with a proper shape, the feeding effect of the riser is improved as much as possible on the premise of ensuring the arrangement space of the riser and facilitating the drawing.
Preferably, a riser head patch is additionally arranged at a hot junction at the connecting part of the rocker arm shell and the transition frame so as to prolong the feeding distance of the second open riser head, realize sequential solidification and enhance feeding effect and eliminate the defects of shrinkage cavity and looseness at the lower part of the casting.
Furthermore, the first and second open risers are 850mm × 500mm × 750mm, the third open riser is 400mm × 750mm, the fourth and fifth dark risers are 320mm × 415mm, and the sixth, seventh, eighth and ninth dark risers are 280mm × 420mm × 365mm, 220mm × 330mm × 285mm, 260mm × 390mm × 340mm and 260mm × 310mm in sequence.
With regard to the core print design, the core print is a technological measure for supporting and fixing the loam core, which can make the loam core work reliably. For casting of a 3050 shearer loader arm casing, the dimensions of each core print are preferably determined as follows: the lengths of the core print on the coal wall side and the mining side of the planet head mounting cylinder are respectively 350mm and 300mm, the lengths of the core print on the coal wall side of one shaft and the core print on the coal wall side of the other shaft are both 250mm, the lengths of the core prints on the four shafts to the seven shafts on the coal wall side are 550mm, the length of the core print on the hole position of the motor cylinder is 250mm, and the length of the core print on the large plane position on the mining side of the arm support is 400 mm. The core head with the size can ensure that the position of the sand core is correct and stable on the premise of not increasing the size of the sand mold, and the sand core is prevented from being crushed.
And the sixth blind riser is positioned above the sand core heads on the four to seven shafts on the side of the coal wall.
The draft of the core print is preferably 3 degrees, so that the sand mould can be effectively prevented from being damaged during core setting and mould assembling. Under the condition of comprehensively considering the deformation of the clay core in the processes of manufacturing, transporting, drying and the like and the dimensional errors of a casting mould and a core box, the core print gap is preferably 4.0mm, and the smooth assembly of the core print and the core seat can be ensured.
The negative value of parting is 3mm, and the upper and lower symmetrical distribution is 1.5mm respectively.
With respect to the external chiller, the following external chiller design sizes and numbers may be further employed: the size of the first group of external chilling blocks is 220mm multiplied by 100mm, the number of the first group of external chilling blocks is 30-40 blocks, the size of the second group of external chilling blocks is 200mm multiplied by 100mm, the number of the second group of external chilling blocks is 4-6 blocks, the size of the third group of external chilling blocks is 200mm multiplied by 100mm, the number of the third group of external chilling blocks is 15-25 blocks, the size of the fourth group of conformal external chilling blocks is 400mm multiplied by 200mm multiplied by 100mm, and the number of the fourth group of conformal external chilling blocks is 3-5 blocks. The casting cast by the process has smooth surface, clear outline and no obvious defects of pores, folds and the like.
According to actual casting practice, the density of the cast product is best when the number of the first group to the fourth group of external chills is preferably 40, 4, 20 and 3 in turn.
Furthermore, as shown in fig. 6, it is preferable to arrange an external chiller 4-5 at the fillet position where the three axes of the inner cavity of the arm support are connected with the root of the motor barrel, so that the fillet position where the three axes of the inner cavity of the arm support are connected with the root of the motor barrel is ensured not to generate crack defects.
The straight pouring channel of the pouring system 3 adopts one channel with the diameter of 120mm, the horizontal pouring channel adopts two channels with the diameter of 100mm, the two channels are separated from the middle to the two sides, and the inner pouring channel adopts two channels with the diameter of 100 mm.
The casting process of the rocker arm shell of the ultra-thick coal seam mining machine further comprises the following steps of heat treatment after demolding and cutting of a casting head: after demolding, normalizing the casting with a casting head at the normalizing temperature of 910 +/-10 ℃ for 8-10 hours. After normalizing treatment, the riser is thermally cut and planed at the temperature of more than 250 ℃. Because the casting material still contains Cr, inclusions and oxidation films can still be generated in molten steel, the molten steel is thickened, the fluidity is reduced, and the volume shrinkage and the hot cracking tendency in the casting condensation process are increased, so that the hot cutting of the feeder head instead of the cold cutting can effectively avoid the crack generation of the cutter head. And the hot planing is to carry out carbon planing treatment on the flash, the burr and the root of the non-machined part of the riser after the riser is subjected to hot cutting. And (4) tempering treatment is carried out after carbon planing, wherein the tempering temperature is 650 ℃, and the heat preservation time is 6-8 hours.
The casting process of the rocker arm shell of the super-thick coal seam mining machine further comprises the following molten steel smelting and pouring processes: the pre-furnace deoxidation is preferably carried out in the steel-making process, rare earth silicon is adopted in a steel ladle for modification treatment and a steel ladle bottom argon blowing technology, so that the contents of gas and harmful elements in the molten steel are reduced, and the purity of the molten steel is strictly controlled. The tapping temperature is preferably controlled to be 1580-.
The casting temperature is preferably controlled at 1520-1560 ℃, and a thermocouple thermometer can be used for measuring the temperature. And during pouring, slow pouring is firstly carried out, then fast pouring with large flow is carried out, and finally slow pouring is carried out, after the pouring is completed, the pouring is stopped for 15 minutes, and then the pouring is stopped for 5 minutes, and the pouring is carried out once. The pouring temperature and the pouring speed are well controlled, so that the feeding capacity of molten steel is increased, and the compact structure of a casting is ensured. The ladle adopts a bottom pouring type casting ladle, a newly built ladle cannot be used, and the ladle must be kept dry.
By adopting the brand new casting process, the casting process of the rocker arm shell casting of the ultra-thick coal seam mining machine is improved, the casting quality is further improved, the casting density is improved, and the casting defects of shrinkage holes, looseness, cracks and the like in different degrees at the middle part of the connection between the root of the motor cylinder and the three shafts of the rocker arm shell, the thick part of the connection surface of the transition frame on the rocker arm shell (the outer end surface close to the motor cylinder in the length direction of the rocker arm shell), the inner part of the planet head mounting cylinder and the like produced in the original casting process are eliminated, so that the problem of oil leakage caused by the casting defects of the shell is successfully solved.
The 3050 shearer referred to herein is an abbreviation of MG1100/3050-WD series shearer.
Claims (11)
1. A process for casting a rocker arm shell of a super-thick coal seam mining machine is characterized by comprising the following steps: the method is characterized in that ZG25MnNi material is adopted for casting, a plane passing through the motor barrel axis and the planet head installation barrel axis of a coal cutter rocker arm shell is taken as a parting surface, a sand box molding casting mode combining a real mold and a core assembly is adopted, an outer sand mold and a clay core are made of resin sand, a casting water channel part, a round corner part and a corner part on the clay core are made of chromite sand, the rest parts of a sand mold adopt 40-80-mesh sea sand, the coating adopts alcohol-based zircon powder coating, an open bottom return type pouring system and a horizontal pouring mode are adopted, the pouring system is all made of ceramic tubes, a first open riser and a second open riser are respectively arranged above the planet head installation barrel and the motor barrel, a third open riser is arranged at the joint of the upper plane of the motor barrel and an arm frame, and fourth dark risers are sequentially arranged at intervals by taking the low-speed end of the arm frame as the starting point at the edge of the upper plane and the side close to the coal wall of the arm frame, The fourth blind riser and the fifth blind riser are positioned on the mining side of the planet head mounting cylinder, the seventh blind riser and the eighth blind riser are respectively arranged on the upper plane of the arm support and the low-speed end part and the middle part of the arm support close to the edge of the mining side, the ninth blind riser is arranged on the upper plane of the arm support and the four-axis to seven-axis positions of the coal wall side, the first group of external chillers are arranged on the plane of the lower box of the motor cylinder and the triangular joint part of the lower part of the motor cylinder and the arm support, the second group of external chillers are arranged on the end surface of one axis, the third group of external chillers are arranged on the coal wall side and the edge of the mining side along the water channel at the bottom of the arm support, and the fourth group of conformal external chillers are arranged at the bottom of the lower box of the planet head mounting cylinder.
2. The process for casting the rocker arm shell of the ultra-thick coal seam mining machine according to claim 1, characterized in that: the fourth blind riser and the fifth blind riser are heating risers, the rest risers are heat-insulating risers, and the first open riser and the second open riser are wooden risers.
3. The process for casting the rocker arm shell of the ultra-thick coal seam mining machine as claimed in claim 2, wherein: the first open riser and the second open riser are cuboid risers, the sixth blind riser, the seventh blind riser and the eighth blind riser are long cylindrical risers, the rest risers are cylindrical risers, and the blind risers are spherical-top cylindrical risers.
4. The process for casting the rocker arm shell of the ultra-thick coal seam mining machine as claimed in claim 3, wherein: the first and second open risers are 850mm multiplied by 500mm multiplied by 750mm, the third open riser is 400mm multiplied by 750mm, the fourth and fifth dark risers are 320mm multiplied by 415mm, and the sixth, seventh, eighth and ninth dark risers are 280mm multiplied by 420mm multiplied by 365mm, 220mm multiplied by 330mm multiplied by 285mm, 260mm multiplied by 390mm multiplied by 340mm and 260mm multiplied by 310mm in sequence.
5. The casting process of the rocker arm shell of the ultra-thick coal seam mining machine according to claim 1, characterized in that: the lengths of the core print on the coal wall side and the mining side of the planet head installation barrel are respectively 350mm and 300mm, the lengths of the core print on the coal wall side of one shaft and the core print on the coal wall side of the other shaft are both 250mm, the lengths of the core prints on the four shafts to the seven shafts on the coal wall side are 550mm, the length of the core print on the hole position of the motor barrel is 250mm, and the length of the core print corresponding to the large plane on the mining side of the arm support is 400 mm.
6. The process for casting the rocker arm shell of the ultra-thick coal seam mining machine as claimed in claim 1, 2, 3, 4 or 5, wherein: the size of the first group of external chilling blocks is 220mm multiplied by 100mm, the number of the first group of external chilling blocks is 30-40 blocks, the size of the second group of external chilling blocks is 200mm multiplied by 100mm, the number of the second group of external chilling blocks is 4-6 blocks, the size of the third group of external chilling blocks is 200mm multiplied by 100mm, the number of the third group of external chilling blocks is 15-25 blocks, the size of the fourth group of conformal external chilling blocks is 400mm multiplied by 200mm multiplied by 100mm, and the number of the fourth group of conformal external chilling blocks is 3-5 blocks.
7. The process for casting the rocker arm shell of the ultra-thick coal seam mining machine as claimed in claim 6, wherein: the number of the first group to the fourth group of external chills is 40, 4, 20 and 3 in sequence.
8. The process for casting the rocker arm shell of the ultra-thick coal seam mining machine as claimed in claim 1, 2, 3, 4, 5, 6 or 7, wherein: and an external chill is arranged at the position of a fillet connected with the root part of the motor barrel at the three axes of the inner cavity of the arm support.
9. The process for casting the rocker arm shell of the extra-thick coal seam mining machine as claimed in claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein: one straight pouring channel with the diameter of 120mm is adopted in the pouring system, two transverse pouring channels with the diameter of 100mm are adopted and are separated from the middle to two sides, and two inner pouring channels with the diameter of 100mm are adopted in the inner pouring channel.
10. The process for casting the rocker arm shell of the ultra-thick coal seam mining machine according to claim 9, characterized in that: after demolding, normalizing the casting with a casting head at 910 +/-10 ℃ for 8-10 hours, hot cutting and hot planing the casting head at the temperature of more than 250 ℃ after normalizing, carrying out carbon planing on the flash, burr and the root of the non-machined part of the casting after hot cutting of the casting head, and tempering at 650 ℃ for 6-8 hours after carbon planing.
11. The process for casting the rocker arm shell of the ultra-thick coal seam mining machine as claimed in claim 10, wherein: performing stokehole deoxidation in the steel making process, performing modification treatment in a steel ladle by adopting rare earth silicon, controlling the tapping temperature at 1580-.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116618582A (en) * | 2023-06-01 | 2023-08-22 | 辽宁工程技术大学 | Casting system for rocker arm shell of coal mining machine |
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| CN215657682U (en) * | 2021-09-17 | 2022-01-28 | 新乡市长城铸钢有限公司 | Molding sand box of lower rocker arm |
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| JPH04200853A (en) * | 1990-11-29 | 1992-07-21 | Suzuki Motor Corp | Production of rocker arm |
| US5582142A (en) * | 1994-05-04 | 1996-12-10 | Dr. Ing. H.C.F. Porsche Ag | Rocker arm |
| WO2003057387A1 (en) * | 2002-01-08 | 2003-07-17 | Jose Uribesalgo Beitia | Production of one-piece supports for engine rocker shafts |
| KR20040050287A (en) * | 2002-12-10 | 2004-06-16 | 최명구 | Aluminium rocker arm and method of manufacturing therof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116618582A (en) * | 2023-06-01 | 2023-08-22 | 辽宁工程技术大学 | Casting system for rocker arm shell of coal mining machine |
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