Production method of high-standard sintering pallet car of nodular cast iron 500-7

Abstract

A high-standard physical and chemical index ductile iron 500-7 sintering bogie production method, comprising: 1) the upper box is a plane, and the shaft head is in the lower part; 2) the straight sprue adopts a Φ60-80mm refractory brick pipe, the inner gate size is Φ30-40mm, 18-24 channels are uniformly distributed, one trapezoidal cross gate is arranged on the left side and the right side of the length direction of the vehicle body, and the cross gate end is extended by 50-100mm; 3) the molten iron temperature is above 1450 DEG C, and the standing time is above 5min, the tapping temperature is 1450-1460 DEG C; 4) pure copper and pure tin are added with the molten iron flow; 5) after the molten iron is tapped, spheroidizing treatment is carried out: a composite spheroidizing agent and a composite inoculant are adopted, the spheroidizing agent addition amount is 0.9%-1.1%, and the inoculant addition amount is 1.2%-1.3%; 6) the time from spheroidizing start to pouring end is controlled to be less than 20min. The chemical element proportioning of spheroidizing rate, elongation rate and spheroidizing grade is accurately controlled, and the corresponding smelting and pouring control method is matched, so that the performance indexes of product spheroidizing rate 90%, spheroidizing grade 2, elongation rate 7%-15% and graphite size 6 are obtained.

Description

Technical Field

[0001] This invention relates to the field of mechanical manufacturing technology, and in particular to a production method for a high-standard sintering trolley for ductile iron 500-7. Background Technology

[0002] my country is a major foundry country, producing over 50 million tons of castings annually. Gray iron castings account for 41.9% of this, while ductile iron castings account for 29.5%. Due to its good toughness and high strength, the application share of ductile iron is increasing year by year. The production technology for ordinary ductile iron is relatively mature.

[0003] Commonly used sintering machines and sintering trolleys in the market ( Figure 1 , Figure 2 These are generally ductile iron parts with relatively complex structures, requiring a grade of QT500-7, and generally requiring R... m >500MPa, elongation A>7, spheroidization rate 85%, spheroidization grade generally required to be level 3, graphite size grade 5, HB150. Through years of domestic practice, by selecting the type of spheroidizing agent, matching the amount added, using the inoculant appropriately, and meeting the requirements for residual magnesium and rare earth elements, this grade of ductile iron can meet the above performance requirements during production.

[0004] However, facing fierce competition both domestically and internationally, and the increasing demand from users for long-life and high-quality components, the market is now imposing stringent requirements on the various physical and chemical properties of ductile iron QT500-7 to further improve the online service life of sintering trolleys. These properties far exceed national standards. Specifically, the requirements include a spheroidization rate of 90%, a spheroidization grade of 2, precise control of elongation between 7% and 12%, and a graphite size of 6 grades. These requirements dictate that the proportion of castings in the overall project must exceed 88%. Summary of the Invention

[0005] The purpose of this invention is to provide a production method for a high-standard sintering trolley for ductile iron 500-7, which precisely controls the chemical element ratios of spheroidization rate, elongation, and spheroidization grade, and is combined with corresponding smelting and casting control methods to achieve the performance requirements of 90% spheroidization rate, grade 2 spheroidization, precisely controlled elongation of 7%-15%, and graphite size grade 6.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A production method for a high-standard physicochemical properties ductile iron 500-7 sintering trolley specifically includes two parts: molding and smelting treatment, and casting.

[0008] The first part of the design includes the following methods:

[0009] 1) The upper box is flat, which facilitates casting production operations and is highly efficient; the shaft head is at the bottom, which is conducive to shaft head feeding and prevents shrinkage defects; the middle box is formed by sand cores; the middle box is composed of 3 or 6 identical sand cores, which is convenient for operation.

[0010] The molding process uses self-hardening sand. The primary raw sand for the intermediate box core is washed quartz sand with a particle size of 40-70 mesh. The particle size of the raw sand is the key to ensuring surface quality. The binder is furan resin sand, with the binder added at 0.8%-1.2% of the weight of the raw sand. The curing agent is added at 30%-50% of the weight of the binder. The molding is produced by mixing the sand using a continuous sand mixer.

[0011] 2) The sprue uses a high-quality refractory brick pipe with a diameter of 60-80mm. A casting ceramic filter is placed at the connection between the sprue and the runner. The ingate has a diameter of 30-40mm and is evenly distributed with 18-24 runners. There is one trapezoidal runner on each side along the length of the car body. The cross-sectional dimensions of the runner are (100-90)mm at the top, (90-80)mm at the bottom, and (70-80)mm at the top. The runner is extended by 50-100mm at the end to ensure pouring speed and slag accumulation effect.

[0012] The second part, smelting and casting, includes the following methods:

[0013] 1) After the molten iron in the furnace reaches a temperature of 1450℃ or above, it is allowed to stand for more than 5 minutes before being taken out of the furnace. The temperature at which the iron is taken out of the furnace is 1450~1460℃. Q10 pig iron and low carbon scrap steel are used for the molten iron smelting. The alloy is ordinary high carbon ferromanganese and 75 silicon ferro.

[0014] The chemical composition of the molten iron, by mass percentage, is: C 3.2%–3.8%, Si 1.3%–1.4%, Mn 0.5%–0.8%, P≤0.04%, S≤0.02%, with the remainder being Fe and unavoidable impurities.

[0015] 2) Add pure copper and pure tin along with the molten iron during the tapping process, and control the Cu content in the molten iron to be 0.15wt% to 0.5wt% and Sn content to be 0.002wt% to 0.02wt%.

[0016] 3) After the molten iron is tapped from the furnace, it undergoes spheroidizing treatment: A dam or spheroidizing treatment pit with a diameter of more than 200 mm is built in the middle of the bottom of the ladle. The "sandwich" treatment method is adopted, that is, first add spheroidizing agent, then cover with inoculant, and finally cover with 10-20 mm thick iron filings. After tapping and spheroidizing, the slag is removed.

[0017] To enhance the nucleation ability of molten iron and ensure high-level spheroidization of graphite, a composite spheroidizing agent and a composite inoculant are used. The amount of composite spheroidizing agent added is 0.9% to 1.1% of the molten iron by mass percentage, and the amount of composite inoculant added is 1.2% to 1.3% of the molten iron by mass percentage.

[0018] The composite spheroidizing agent contains Si, Mg, and Re; the composite inoculant contains Si, Ca, Ba, and Zr. This is beneficial for the formation and morphology of graphite, and promotes finer and rounder microstructure.

[0019] 4) Strictly control the time from the start of spheroidization to the end of casting to be less than 20 minutes, and the optimal control time is within 15 minutes.

[0020] A production method for a high-standard sintering trolley for ductile iron 500-7. The sintering trolley for ductile iron 500-7 produced has the following chemical composition by mass percentage: C 3.2%–3.8%, Si 2.2%–2.6%, Mn 0.5%–0.8%, P≤0.04%, S≤0.02%, Cu 0.15%–0.5%, Sn 0.002%–0.02%; the remainder is Fe and trace amounts of Mg, Re, Ca, Ba, Zr and unavoidable impurities.

[0021] As a preferred option, the chemical composition of the ductile iron 500-7 sintering trolley, by mass percentage, is: C 3.35%–3.55%, Si 2.4%–2.55%, Mn 0.6%–0.7%, P ≤ 0.04%, S 0.008%–0.015%, Cu 0.2%–0.25%, Sn 0.002%–0.02%; the remainder being Fe and trace amounts of Mg, Re, Ca, Ba, Zr, and unavoidable impurities.

[0022] The physical and chemical properties of the sintering trolley for ductile iron 500-7 are as follows: spheroidization rate above 90%; spheroidization grade above 2; graphite size above 6; elongation rate of 7-15%.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] This invention can improve the physicochemical properties of sintering sintering trolleys (500-7 type) to a spheroidization rate of 90%, a spheroidization grade of 2, a graphite size of grade 6 or higher, and an elongation of 7%-15%. This effectively extends the service life of the sintering trolley. These requirements are unprecedented in China, and the product performance is at the leading level in the sintering machine and sintering trolley industry. Attached Figure Description

[0025] Figure 1 This is a picture of the actual body of the sintering trolley.

[0026] Figure 2 This is the front view of the sintering trolley part drawing.

[0027] Figure 3 This is a top view of the sintering trolley parts drawing.

[0028] Figure 4 This is the front view of the trolley casting process diagram of the present invention.

[0029] Figure 5 This is a top view of the casting process diagram of the trolley of this invention.

[0030] Figure 6 This is a partial enlarged view of the parting line end area in the casting process of the trolley of this invention.

[0031] Figure 7 This is a partial enlarged view of the design of the sprue and ingate of the casting system for the trolley casting process of this invention.

[0032] In the diagram: 1-Upper box surface, 2-Lower box surface, 3-1# sand core, 4-2# sand core, 5-Inner gating, 6-Vertical gating, 7-Horizontal gating, 8-Intermediate box body, 9-Shaft head. Detailed Implementation

[0033] The embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0034] See Figures 1-7 This invention discloses a method for producing high-standard sintering ductile iron 500-7 using a sintering trolley, specifically comprising:

[0035] 1) The upper box is flat, with the shaft head 9 at the bottom. The middle box body 8 is formed using sand cores. The shaft heads 9 on both sides are formed using end-head sand cores #1 3 to ensure accurate shape and position dimensions of the shaft heads 9. The four shaft holes are formed using sand cores #2 4. All sand cores are positioned entirely by the core head, and the wooden pattern is machined as a whole on a CNC machine tool according to the drawing to ensure dimensional accuracy of each part.

[0036] 2) The straight pouring channel 6 uses refractory brick pipes with a diameter of 60-80mm. The inner pouring channel 5 has a diameter of 30-40mm and is evenly distributed with 18-24 channels. There is one trapezoidal horizontal pouring channel 7 on each side of the car body along the length direction. The cross-sectional dimensions of the horizontal pouring channel 7 are (100-90)mm at the top, (90-80)mm at the bottom, and (70-80)mm at the top. The end of the horizontal pouring channel 7 is extended by 50-100mm to ensure the pouring speed and slag accumulation effect.

[0037] 3) After the molten iron in the furnace reaches a temperature of 1450℃ or higher, let it stand for more than 5 minutes before removing it from the furnace. The temperature at which it is removed from the furnace is 1450~1460℃.

[0038] 4) Add pure copper and pure tin along with the molten iron when it comes out of the furnace, and control the Cu content in the molten iron to be 0.15wt%~0.5wt% and Sn to be 0.002wt%~0.02wt%.

[0039] 5) After the molten iron is tapped from the furnace, it undergoes spheroidizing treatment: the “sandwich” treatment method is adopted, that is, first add spheroidizing agent, then cover with inoculant, and finally cover with 10-20mm thick iron filings. After spheroidizing, the slag is removed.

[0040] A composite spheroidizing agent and a composite inoculant are used. The amount of the composite spheroidizing agent added is 0.9% to 1.1% of the molten iron by mass percentage, and the amount of the composite inoculant added is 1.2% to 1.3% of the molten iron by mass percentage.

[0041] 6) Control the time from the start of spheroidization after the furnace is removed from the furnace to the end of the pouring process to be less than 20 minutes.

[0042] The intermediate box uses a combination of 3 or 6 identical sand cores.

[0043] The original sand for the 8 cores in the intermediate chamber is washed quartz sand with a particle size of 40-70 mesh. The binder is furan resin sand, and the amount of binder added is 0.8%-1.2% of the weight of the original sand. The amount of curing agent added is 30%-50% of the weight of the binder.

[0044] The molten iron smelting process uses pig iron and low-carbon scrap steel as raw materials, and the alloy consists of high-carbon ferromanganese and 75% ferrosilicon.

[0045] The composite spheroidizing agent contains Si, Mg, and Re; the composite inoculant contains Si, Ca, Ba, and Zr.

[0046] The time from the start of spheroidization after furnace exit to the end of casting should be controlled to be within 15 minutes.

[0047] The chemical composition of the molten iron in step 3) by mass percentage is: C 3.2%~3.8%, Si 1.3%~1.4%, Mn 0.5%~0.8%, P≤0.04%, S≤0.02%, with the remainder being Fe and unavoidable impurities.

[0048] A production method for a high-standard sintering trolley for ductile iron 500-7. The sintering trolley for ductile iron 500-7 produced has the following chemical composition by mass percentage: C 3.2%–3.8%, Si 2.2%–2.6%, Mn 0.5%–0.8%, P≤0.04%, S≤0.02%, Cu 0.15%–0.5%, Sn 0.002%–0.02%; the remainder is Fe, Mg, Re, Ca, Ba, Zr, and unavoidable impurities.

[0049] The physical and chemical properties of the sintering trolley for ductile iron 500-7 are as follows: spheroidization rate above 90%; spheroidization grade above 2; graphite size above 6; elongation rate of 7-15%.

[0050] Example 1:

[0051] A production method for a high-standard physicochemical properties ductile iron 500-7 sintering trolley specifically includes two parts: molding and smelting treatment, and casting.

[0052] The first part of the design includes the following methods:

[0053] 1) The upper box is flat, with the shaft head 9 at the bottom, which facilitates casting production operations and is highly efficient. It also helps to compensate for the shrinkage of the shaft head and prevent shrinkage defects. The middle box 8 is composed of 3 identical sand cores.

[0054] The molding process uses self-hardening sand. The primary raw sand for the eight sand cores in the middle box is 40-mesh washed quartz sand, as the particle size of the raw sand is crucial to ensuring surface quality. The binder is furan resin sand, with the binder added at 0.8% of the weight of the raw sand and the curing agent added at 30% of the weight of the binder. The molding is produced by mixing the sand using a continuous sand mixer.

[0055] 2) The straight pouring channel 6 is made of Φ60mm high-quality refractory brick pipe, the inner pouring channel 5 is Φ30mm in size, with 24 channels evenly distributed, and one trapezoidal horizontal pouring channel 7 on each side of the car body length direction. The cross-sectional dimensions of the horizontal pouring channel 7 are 90mm at the top, 80mm at the bottom, and 80mm at the top. The end of the horizontal pouring channel 7 is extended by 50mm to ensure the pouring speed and slag accumulation effect.

[0056] The second part, smelting and casting, includes the following methods:

[0057] 1) After the molten iron in the furnace reaches a temperature of 1460℃, it is allowed to stand for more than 5 minutes before being taken out of the furnace at a temperature of 1450℃. The molten iron is produced using Q10 pig iron and low-carbon scrap steel as raw materials, and the alloy consists of ordinary high-carbon ferromanganese and 75 ferrosilicon.

[0058] The chemical composition of the molten iron, by mass percentage, is: C 3.35%, Si 1.3%, Mn 0.5%, P 0.03%, S 0.015%, with the remainder being Fe and unavoidable impurities.

[0059] 2) Pure copper and pure tin are added along with the molten iron during the tapping process, and the Cu content in the molten iron is controlled to be 0.2 wt% and Sn 0.003 wt%.

[0060] 3) After the molten iron is tapped from the furnace, it undergoes spheroidizing treatment: A dam or spheroidizing treatment pit with a diameter of more than 200 mm is built in the middle of the bottom of the ladle. The "sandwich" treatment method is adopted, that is, first add spheroidizing agent, then cover with inoculant, and finally cover with 15 mm thick iron filings. After tapping and spheroidizing, the slag is removed.

[0061] To enhance the nucleation ability of molten iron and ensure high-level spheroidization of graphite, a composite spheroidizing agent and a composite inoculant are used. The amount of composite spheroidizing agent added is 1.1% of the molten iron by mass percentage, and the amount of composite inoculant added is 1.2% of the molten iron by mass percentage.

[0062] The composite spheroidizing agent contains Si, Mg, and Re; the composite inoculant contains Si, Ca, Ba, and Zr.

[0063] 4) Strictly control the time from the start of spheroidization after furnace exit to the end of casting to be 14 minutes.

[0064] The sintering trolley of ductile iron 500-7 used in the example has the following chemical composition by mass percentage: C 3.35%, Si 2.5%, Mn 0.65%, P 0.03%, S 0.015%, Cu 0.2%, Sn 0.003%; the remainder is Fe and trace amounts of Mg, Re, Ca, Ba, Zr and unavoidable impurities.

[0065] The physicochemical properties of the sintering trolley for ductile iron 500-7 in this embodiment are as follows: spheroidization rate 90%; spheroidization grade 2; graphite size grade 6 or above; elongation 15%.

[0066] Example 2:

[0067] A production method for a high-standard physicochemical properties ductile iron 500-7 sintering trolley specifically includes two parts: molding and smelting treatment, and casting.

[0068] The first part of the design includes the following methods:

[0069] 1) The upper box is flat, with the shaft head 9 at the bottom; the middle box 8 is made of 6 identical sand cores.

[0070] The self-hardening sand molding process is adopted. The primary raw sand for the 8 sand cores in the middle box is 60-mesh washed quartz sand. The particle size of the raw sand is the key to ensuring surface quality. The binder is furan resin sand, with the binder added at 1.0% of the weight of the raw sand and the curing agent added at 40% of the weight of the binder. The molding is produced by mixing and molding using a continuous sand mixer.

[0071] 2) The straight pouring channel 6 uses a Φ70mm refractory brick pipe, the inner pouring channel 5 is Φ35mm in size, with 20 channels evenly distributed, and one trapezoidal horizontal pouring channel 7 on each side of the car body length direction. The cross-sectional dimensions of the horizontal pouring channel 7 are 90mm at the top, 80mm at the bottom, and 80mm at the top. The end of the horizontal pouring channel 7 is extended by 90mm to ensure the pouring speed and slag accumulation effect.

[0072] The second part, smelting and casting, includes the following methods:

[0073] 1) After the molten iron in the furnace reaches a temperature of 1460℃ or above, it is allowed to stand for more than 5 minutes before being taken out of the furnace at a temperature of 1455℃. The molten iron is produced using Q10 pig iron and low-carbon scrap steel as raw materials, and the alloy consists of ordinary high-carbon ferromanganese and 75 ferrosilicon.

[0074] The chemical composition of the molten iron, by mass percentage, is: C 3.55%, Si 1.4%, Mn 0.6%, P 0.02%, S 0.008%, with the remainder being Fe and unavoidable impurities.

[0075] 2) Pure copper and pure tin are added along with the molten iron during the tapping process, and the Cu content in the molten iron is controlled to be 0.25 wt% and Sn to be 0.006 wt%.

[0076] 3) After the molten iron is tapped from the furnace, it undergoes spheroidizing treatment: A dam or spheroidizing treatment pit with a diameter of more than 200 mm is built in the middle of the bottom of the ladle. The "sandwich" treatment method is adopted, that is, first add spheroidizing agent, then cover with inoculant, and finally cover with 10-20 mm thick iron filings. After tapping and spheroidizing, the slag is removed.

[0077] To enhance the nucleation ability of molten iron and ensure high-level spheroidization of graphite, a composite spheroidizing agent and a composite inoculant are used. The amount of composite spheroidizing agent added is 1.0% of the molten iron by mass percentage, and the amount of composite inoculant added is 1.3% of the molten iron by mass percentage.

[0078] The composite spheroidizing agent contains Si, Mg, and Re; the composite inoculant contains Si, Ca, Ba, and Zr.

[0079] 4) Strictly control the time from the start of spheroidization after furnace exit to the end of casting to be 15 minutes.

[0080] The sintering trolley for ductile iron 500-7 in this embodiment has the following chemical composition by mass percentage: C 3.55%, Si 2.4%, Mn 0.7%, P 0.02%, S 0.008%, Cu 0.25%, Sn 0.006%; the remainder is Fe and trace amounts of Mg, Re, Ca, Ba, Zr and unavoidable impurities.

[0081] The physicochemical properties of the ductile iron 500-7 sintering trolley in this embodiment are as follows: spheroidization rate 92%; spheroidization grade 2; graphite size grade 6; elongation 14%.

[0082] Example 3:

[0083] A production method for a high-standard physicochemical properties ductile iron 500-7 sintering trolley specifically includes two parts: molding and smelting treatment, and casting.

[0084] The first part of the design includes the following methods:

[0085] 1) The upper box is flat, the shaft head 9 is at the bottom, and the middle box 8 is composed of 6 identical sand cores.

[0086] The self-hardening sand molding process is adopted. The primary raw sand for the 8 sand cores in the middle box is 50-mesh washed quartz sand. The particle size of the raw sand is the key to ensuring surface quality. The binder is furan resin sand, with the binder added at 0.9% of the weight of the raw sand and the curing agent added at 35% of the weight of the binder. The molding is produced by mixing and molding using a continuous sand mixer.

[0087] 2) The straight pouring channel 6 uses a 65mm refractory brick pipe, the inner pouring channel 5 is 30mm in size, with 22 channels evenly distributed, and one trapezoidal horizontal pouring channel 7 on each side of the car body length direction. The cross-sectional dimensions of the horizontal pouring channel 7 are 90mm at the top, 80mm at the bottom, and 80mm at the top. The end of the horizontal pouring channel 7 is extended by 80mm to ensure the pouring speed and slag accumulation effect.

[0088] The second part, smelting and casting, includes the following methods:

[0089] 1) After the molten iron in the furnace reaches a temperature of 1460℃, it is allowed to stand for more than 5 minutes before being taken out of the furnace at a temperature of 1452℃. The molten iron is produced using Q10 pig iron and low-carbon scrap steel as raw materials, and the alloy consists of ordinary high-carbon ferromanganese and 75 ferrosilicon.

[0090] The chemical composition of the molten iron, by mass percentage, is: C 3.7%, Si 1.3%, Mn 0.7%, P 0.01%, S 0.01%, with the remainder being Fe and unavoidable impurities.

[0091] 2) Pure copper and pure tin are added with the molten iron as it is poured out of the furnace, and the Cu content in the molten iron is controlled to be 0.3 wt% and Sn 0.015 wt%.

[0092] 3) After the molten iron is tapped from the furnace, it undergoes spheroidizing treatment: A dam or spheroidizing treatment pit with a diameter of more than 200 mm is built in the middle of the bottom of the ladle. The "sandwich" treatment method is adopted, that is, first add spheroidizing agent, then cover with inoculant, and finally cover with 10-20 mm thick iron filings. After tapping and spheroidizing, the slag is removed.

[0093] To enhance the nucleation ability of molten iron and ensure high-level spheroidization of graphite, a composite spheroidizing agent and a composite inoculant are used. The amount of composite spheroidizing agent added is 1.1% of the molten iron by mass percentage, and the amount of composite inoculant added is 1.2% of the molten iron by mass percentage.

[0094] The composite spheroidizing agent contains Si, Mg, and Re; the composite inoculant contains Si, Ca, Ba, and Zr.

[0095] 4) Strictly control the time from the start of spheroidization after furnace exit to the end of casting to be 10 minutes.

[0096] The chemical composition of the sintering trolley for ductile iron 500-7 in this embodiment, by mass percentage, is: C 3.7%, Si 2.3%, Mn 0.55%, P 0.01%, S 0.01%, Cu 0.3%, Sn 0.015%; the remainder is Fe and trace amounts of Mg, Re, Ca, Ba, Zr and unavoidable impurities.

[0097] The physical and chemical properties of the sintering trolley for ductile iron 500-7 in the example are as follows: spheroidization rate 90%; spheroidization grade 2; graphite size grade 6; elongation 13%.

Claims

1. A production method of high-standard physical and chemical index nodular cast iron 500-7 sintering bogie, characterized in that, Specifically comprising: 1) the upper box is flat, the shaft head is in the lower part, and the middle box body is formed by a sand core; 2) the sprue is made of a Φ60-80mm refractory brick pipe, the inner gate size is Φ30-40mm, there are 18-24 gates, and there is one trapezoidal cross gate on each side of the vehicle length direction; 3) the molten iron is poured out after being kept for more than 5min after being melted in the furnace at a temperature of more than 1450℃, and the pouring-out temperature is 1450-1460℃; 4) pure copper and pure tin are added into the molten iron during pouring-out, and the Cu content in the molten iron is controlled to be 0.15wt%-0.5wt%, and the Sn content is controlled to be 0.002wt%-0.02wt%; 5) the molten iron is poured out and then subjected to spheroidizing treatment: a "sandwich" treatment method is adopted, that is, the spheroidizing agent is added first, then the inoculant is covered, and finally the 10-20mm thick iron scrap is covered; The composite spheroidizing agent and the composite inoculant are used, the adding amount of the composite spheroidizing agent is 0.9wt%-1.1wt% of the molten iron, and the adding amount of the composite inoculant is 1.2wt%-1.3wt% of the molten iron; 6) the time from the spheroidizing start to the pouring end is controlled to be less than 20min; The chemical components contained in the composite spheroidizing agent include Si, Mg and Re; the chemical components contained in the composite inoculant include Si, Ca, Ba and Zr.

2. The production method of high-standard physical and chemical index nodular cast iron 500-7 sintering pallet car according to claim 1, characterized in that, The middle box body is composed of 3 or 6 same sand cores.

3. The production method of high-standard physical and chemical index nodular cast iron 500-7 sintering pallet car according to claim 1 or 2, characterized in that, The original sand of the middle box body sand core is scrubbing quartz sand with a particle size of 40-70 mesh, the binder is furan resin sand, the adding amount of the binder is 0.8wt%-1.2wt% of the original sand, and the adding amount of the curing agent is 30wt%-50wt% of the weight of the binder.

4. The production method of high-standard physical and chemical index nodular cast iron 500-7 sintering pallet car according to claim 1, characterized in that, The molten iron is prepared by using pig iron and low-carbon scrap steel, and the alloy is high-carbon ferromanganese and 75 ferrosilicon.

5. The production method of high-standard physical and chemical index nodular cast iron 500-7 sintering pallet car according to claim 1, characterized in that, The time from the spheroidizing start to the pouring end is controlled to be within 15min.

6. The production method of high-standard physical and chemical index nodular cast iron 500-7 sintering pallet car according to claim 1, characterized in that, The chemical components of the molten iron in step 3) are as follows: C 3.2wt%-3.8wt%, Si 1.3wt%-1.4wt%, Mn 0.5wt%-0.8wt%, P≤0.04wt%, S≤0.02wt%, and the rest is Fe and inevitable impurities.

7. A high-standard-physical-chemical-property spheroidal graphite 500-7 sinter pallet according to any one of claims 1 to 6, wherein the spheroidal graphite 500-7 sinter pallet is produced by the production method according to claim 7. The chemical components are as follows: C 3.2wt%-3.8wt%, Si 2.2wt%-2.6wt%, Mn 0.5wt%-0.8wt%, P≤0.04wt%, S≤0.02wt%, Cu 0.15wt%-0.5wt%, Sn 0.002wt%-0.02wt%, and the rest is Fe and Mg, Re, Ca, Ba, Zr and inevitable impurities.

8. The sinter pallet of ductile iron 500-7 according to claim 7, wherein the sinter pallet of ductile iron 500-7 is produced by the production method of claim 7. The chemical components are as follows: C 3.2wt%-3.8wt%, Si 2.2wt%-2.6wt%, Mn 0.5wt%-0.8wt%, P≤0.04wt%, S≤0.02wt%, Cu 0.15wt%-0.5wt%, Sn 0.002wt%-0.02wt%, and the rest is Fe and Mg, Re, Ca, Ba, Zr and inevitable impurities.

9. The sinter pallet of ductile iron 500-7 according to claim 7 or 8, wherein, The physical and chemical indexes of the ductile iron 500-7 sintering trolley are as follows: the spheroidizing rate is more than 90%; the spheroidizing grade is more than 2; the graphite size is more than 6; and the elongation rate is 7-15%.

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