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Casting method of nodular cast iron axle box for bogie of multiple unit trains below 40 DEG C

A ductile iron and bogie technology, which is applied in the casting field of ductile iron axle boxes for bogies, can solve the problems of increasing production costs and increasing yield strength, and achieves the effects of reducing costs, reducing difficulty, and maintaining stable production quality.

Active Publication Date: 2011-07-13
CHANGZHOU HUADE MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, Ni increases the yield strength and requires heat treatment to obtain a complete ferrite structure. Both the raw material cost of Ni and the difficulty of controlling its content will increase the production cost. At present, there is no relatively perfect and stable casting production process. Can be mass produced

Method used

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  • Casting method of nodular cast iron axle box for bogie of multiple unit trains below 40 DEG C

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1. Raw material preparation

[0029] ①, pig iron, scrap steel, ferrosilicon:

[0030]

[0031] ②, Carburizer: existing commercially available materials;

[0032] ③. Nodulizer: Elkem low-magnesium and low-rare-earth nodulizer, which contains Mg: 5.5%-6.2%, Re: 0.4%-0.6%;

[0033] ④, Inoculant: Elkem low magnesium inoculant, which contains Ba: 2% ~ 3%, Ca: 1% ~ 2%, Ae Max : 1.5%.

[0034] 2. Casting grade: QT400-18LT (-40°C)

[0035] 3. The required chemical composition (mass percentage)

[0036] C: 3.6%-3.8%; Si: 1.9%-2.5%; Mn≤0.05%; P≤0.02; S≤0.05%.

[0037] 4. Mechanical properties achieved by castings

[0038] The tensile strength is above 400MPa, the yield strength is above 260MPa, the elongation is above 18%, and the average impact energy at -40°C is not less than 12J.

[0039] 5. Specific casting process:

[0040] ①, molten iron smelting

[0041] a. Melting in an intermediate frequency induction furnace;

[0042] b. Ratio of charge (%): pig iron 89%-92...

Embodiment 2

[0054] In the manufacturing process of the axle box of ductile iron for the bogie, it is generally carried out in batches with multiple furnaces, that is, the continuous production of several furnace products. In order to improve the utilization rate of production costs, the casting process of the present invention can effectively reduce production costs by utilizing returned materials, which is embodied in the preparation of raw materials, namely:

[0055] 1. 55%-60% of pig iron, 38%-42% of recycled material, 9%-12% of steel scrap, 0.3%-0.4% of ferrosilicon:

[0056] 2. Nodulizer: Elkem low magnesium and low rare earth nodulizer, containing Mg: 5.5%~6.2%, Re: 0.4%~0.6%;

[0057] 3. Inoculant: Elkem low magnesium inoculant, containing Ba: 2%~3%, Ca: 1%~2%, Ae Max : 1.5%.

[0058] It is obvious that compared with Example 1, not only the ratio of pig iron, a high-cost raw material, can be greatly reduced, but also the use of recarburizer will no longer be required.

[0059] E...

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Abstract

The invention discloses a casting method of a nodular cast iron axle box for a bogie of multiple unit trains below 40DEG C. The method comprises the following steps of: preparing 88-92% of pig iron, 8-11% of scrap steel, 1.7-2.0% of ferrosilicon and 0.2-0.24% of carburant by weight; smelting the materials in a medium-frequency induction furnace into molten iron; adjusting the components in weight so that the molten iron comprises 3.6-3.8 of C, 1.9-2.5 of Si, less than or equal to 0.05 of Mn, less than or equal to 0.02 of P, less than or equal to 0.01 of S and balance of Fe; when the furnace temperature reaches 1,550DEG C, purifying the molten iron and performing nodulizing, pouring, mold filling and shakeout; and performing inoculation processing for three times in the nodulizing and pouring process. For the nodular cast iron axle box manufactured by the casting method, the tensile strength reaches 400MPa, the yield strength is 260MPa, the elongation is higher than 18%, the impact work is greater than 12J below -40DEG C, and an axle box with more persistent and stable performance and high quality is provided for the high-speed rails in cold areas.

Description

Technical field: [0001] The invention relates to a casting method of an axle box for a bogie of an EMU, in particular to a casting method for a nodular cast iron axle box for a bogie of an EMU running at minus 40°C. Background technique: [0002] The bogie axle box is a key component of the EMU. The bogie axle box bears the weight of the whole vehicle through the spring. At the same time, the walking wheels and bearings are installed on the bogie axle box, so it bears complex stress states during the operation of the vehicle. The performance and quality of the material are directly related to the operation safety of the bus. [0003] Due to its excellent mechanical properties, processing properties, wear resistance, shock absorption properties and low manufacturing cost, ductile iron is widely used, such as important locomotive structural parts, automotive structural parts, ocean container locks and wind power equipment. Ductile iron is selected. These parts must not only h...

Claims

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Application Information

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IPC IPC(8): B22D3/00B22D1/00C22C33/10
Inventor 丁建中丁杰刘兴艳尤其光孙一彭路辉毛利平孙冬玲
Owner CHANGZHOU HUADE MACHINERY
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