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Application of yttrium-based heavy rare earth magnesium spheroidized cored wire

Application of yttrium-based heavy rare earth magnesium spheroidized cored wire

(Summary description)

Application of yttrium-based heavy rare earth magnesium spheroidized cored wire


Hu Linghai 1, Dong Chengyu 1, Yang Yupeng 2, Liu Yanping 2

(1. FAW Foundry Co., Ltd., Changchun, Jilin 130011; 2. Longnan Longyttrium Heavy Rare Earth Technology Co., Ltd., Ganzhou, Jiangxi 341700)


Abstract: The wire feeding process and the specifications of the cored wire are introduced in detail. The yttrium-based heavy rare earth magnesium nodular cored wire is used to produce automobile weighted axle housing ductile iron castings and wind power castings. The test results show:

(1) Yttrium-based heavy rare earth and high-magnesium spheroidized cored wire is used in the production of large-section ductile iron castings. It has strong resistance to spheroidization recession and can ensure the quality requirements of materials;

(2) The spheroidizing process of feeding thread is a good process to ensure the quality of nodular iron materials and improve the working environment.

Key words: yttrium-based heavy rare earth magnesium spheroidized cored wire; wire feeding spheroidizing process; resistance to spheroidization decline

Chinese Library Classification Number: TG255 Document Identification Code: B Article Number: 1003-8345 (2011) 05-0052-03

DOI: 10.3969/j.issn.1003-8345.2011.05.009


Application of Y-Base Heavy RE-Mg Nodularizing Alloy-Cored Wire
HU Ling-hai1, DONG Cheng-yu1, YANG Yu-peng2, LIU Yan-ping2 (1. First Automotive Foundry Co. Ltd., Changchun 130011, China; 2. Longnan Longyi Rare-earth Material Co. Ltd., Ganzhou
341700, China)


Abstract: A detailed introduction was given to the cored wire injection nodularizing process and the specifications of thecored wire. The Y-base heavy rare earth-containing RE-Mg-Si-Fe nodularizing alloy was used to produce heavy automotive bridge housing and wind power nodular iron castings. The test results showed: (1) when being used for production of heavy section nodular iron castings, the Y -base heavy RE -Mg -Si -Fe nodularizing alloy has relatively strong anti -nodularizing degeneration capacity so it could ensure the casting material quality requirement; (2) Cored wire injection nodularizing process is a excellent process which could ensure the nodular iron casting quality.Keywords: Y -base heavy RE -Mg -Si -Fe nodularizing alloy -cored wire; cored wire injection nodularizing process; anti -nodularizing degeneration capacity

As a result, the number of graphite spheres is small, the spheroidization rate is reduced, and the tendency of slag inclusion, shrinkage and carbides to be increased, and the cost increases. Therefore, the amount of w (Mg residual) should be reduced as much as possible on the premise of ensuring good spheroidization. Generally, the amount of w (Mg residual) ≥ w (S final) amount + 0.024%. To

(3) Case study Case 1: The influence of the amount of w (MgO) in the spheroidizing agent. Plant A uses two spheroidizing agents with both w (Mg) content of 5.8%, w (Mg residual) content is both 0.035%, w (MgO) content is 0.38% and 0.82%, respectively. The latter has poor spheroidization. After calculation, the corresponding effective w (Mg) amounts are 0.033% and 0.030%, respectively.

Case 2: The influence of Mg absorption rate. Plant B uses spheroidizing agent with w (Mg) content of 6%, adding 1.0%, and w (Mg residual) volume fluctuates to 0.042% and 0.030%, respectively. The latter has poor spheroidization, and the corresponding Mg absorption rate 70% and 50% respectively

Case 3: The influence of spheroidizing agent composition fluctuation. Plant B uses a spheroidizing agent, the amount of w (Mg) is 5.6% and 6.3%, which meets the range of standard (6±0.5)%, the amount of addition is 1.0%, and the amount of w (Mg residual) is 0.034%, 0.039 %, the former has poor spheroidization.

Case 4: The influence of RE composition in spheroidizing agent. In the comparative test conducted by Plant C, the spheroidizing agent is only different in RE, which are single Ce and Ce+La. As a result, the number of graphite spheres containing Ce+La increases significantly, and the shrinkage tendency decreases. 4 Conclusion
(1) High-quality raw iron liquid is the prerequisite for producing high-quality ductile iron;
(2) Stable spheroidizing process is a guarantee;
(3) The use of high-quality spheroidizing agent can significantly reduce defects such as poor spheroidization, slag inclusion, shrinkage, and subcutaneous pores, while reducing the amount of spheroidizing agent added.

(Editor: Zhou Gen, E-mail: zhougen_embx@163.com; Editor: Yuan Yajuan, E-mail: xdzt-yyj@126.com)

FAW Foundry Co., Ltd. applies wire feeding spheroidizing process and adopts yttrium-based heavy rare earth high magnesium spheroidizing cored wire to produce automobile weighted axle housing ductile iron castings and wind power ductile iron castings. Practice has proved that the spheroidizing agent has strong anti-balling properties. The mechanical properties of the castings fully meet the material requirements.

1 Casting and its requirements

The name and requirements of the casting are shown in Table 1, and the shape and outline of the casting are shown in Figure 1.

Table 1 Names and requirements of castings

Tab.1 Castings designations and materials requirements

 
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Received Date: 2011-02-20
Revised Date: 2011-06-08
About the author: Hu Linghai (1970.6-), male, Han nationality, from Jilin Yushu, graduated from Wuhan
Senior Engineer, Major in Foundry, College of Engineering.
 
 
2 spheroidizing treatment
The wire feeding spheroidization process is to continuously insert the cored wire containing alloying elements into the bottom of the treatment package through the wire feeding machine. After the action of the high temperature molten iron, the core skin is melted, and the core material (alloying element) immediately contacts the molten iron , The process of spheroidization reaction. According to the introduction of relevant materials, and verified by the practice of the feeding wire spheroidizing process in the first and second foundry of FAW Foundry Co., Ltd.,
This process has the following advantages:
(1) Compared with the spheroidizing process of the flushing method, it can reduce the cost of spheroidizing;
(2) Facilitate centralized treatment of smoke and dust, improve the working environment, and reduce the labor intensity of workers;
(3) The operation is simple, easy to control, easy to realize automatic management, easy to avoid operation errors, and stabilize the quality of spheroidization. The spheroidizing processing station of the feeding line is shown in Figure 2. To
3 The chemical composition and specifications of cored wire are shown in Table 2.
 
Table 2 Chemical composition and specifications of cored wire
Tab. 2 Chemical composition and specification of the cored
wires
 
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4 Feeding line treatment process
(1) The chemical composition of the original molten iron: w(C)3.75%~3.85%, w(Si)1.5%~1.7%, w(Mn) 0.3%~0.5%, w(P)≤0.05%, w(S ) ≤0.03%.
(2) Feeding speed: currently set at 0.45~0.5 m/s when processing molten iron. To
(3) Feeding method: Double-line feeding machine is used, one side is equipped with heavy rare earth core wire, and the other side is equipped with light rare earth core wire, and both sides are fed simultaneously. To
(4) Feeding wire length setting (including 2 m returned after processing): ① side bearing (1 700 kg/bag), set 29 m on both sides; ② clamping flange (3 400 kg/bag), Both sides are set to 58 m; ③ Axle housing (1 400 kg/package), both sides are set to 25 m. To
(5) Treatment of molten iron when it is out of the furnace: When the molten iron is out of the furnace, the ladle is flushed with 0.4% of the Ba-containing high-efficiency inoculant and 0.4% of 75SiFe in the molten iron, and w (Cu), w ( Mn) and w (Sn) amount. Table 3 shows the target components after spheroidization of molten iron. To

5 Feeding wire ball treatment effect
Table 4 shows the results of random inspection of the performance of the casting with a test block (thickness 70 mm). Figure 3, Figure 4, and Figure 5 are the side bearing and clamping method respectively.

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The metallographic photos of the blue and bridge shells have a spheroidization rate of 3 and a ball diameter of 6. The results show that the material quality of all ductile iron castings can meet the requirements of users. To

6 Conclusion
(1) Yttrium-based heavy rare earth and high-magnesium spheroidized cored wire is used in the production of large-section ductile iron castings. It has strong resistance to spheroidization and recession, ensuring the quality requirements of casting materials;
(2) The wire feeding method spheroidizing process is a good process to ensure the quality of ductile iron castings and improve the working environment, and it is worthy of popularization and application.

(Editor: Wang Feng, E-mail: xdzt_wf@fawfc.com) Editor: Zhou Gen, E-mail: zhougen_embx@163.com)

 

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