Sains Malaysiana 43(8)(2014): 1213–1219

 

Morphological Evolution during Partial Re-Melting of AISI D2 Cold-Work Tool Steel

(Perubahan Morfologi Keluli Kerja Sejuk AISI D2 melalui Peleburan-Semula-Separa)

 

 

M.N. MOHAMMED, M.Z. OMAR*, J. SYARIF & M.S. SALLEH

 

Department of Mechanical and Materials Engineering, Faculty of Engineering and Built Environment

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

 

Received: 28 December 2012/Accepted: 26 November 2013

 

ABSTRACT

The impact of isothermal temperature and holding time on the microstructural evolution process is studied. This process is used to produce globular microstructures during partial re-melting of AISI D2 cold work tool steel. The experimental results showed that the optimum process factors should be selected according to the criteria for average grain size and shape factor and also by acknowledging the distribution of the liquid phase around the grains. With increasing isothermal temperature and holding time, the liquid phase starts to diffuse into the grain boundaries and spread more evenly. Also, the equiaxed grains were transformed into near-globular shape, which makes the grain size and shape factor more favourable for thixoforming. The work shows that the optimal process condition for the thixoforming of AISI D2 is 1340°C and 5-min holding time, having a shape factor of 1.13 and a particle size of 51 μm.

 

Keywords: AISI D2; direct partial re-melting; microstructure evolution; thixoforming

 

ABSTRAK

Kesan suhu dan masa memegang proses evolusi mikrostruktur telah dikaji. Proses ini digunakan untuk menghasilkan mikrostruktur globular untuk besi gred AISI D2. Keputusan uji kaji menunjukkan bahawa proses optimum dipilih mengikut kriteria untuk saiz ira purata dan faktor bentuk dan juga menggunakan pengagihan fasa cecair sekitar ira yang terbentuk. Dengan peningkatan suhu dan masa, fasa cecair mula meresap ke dalam sempadan ira dan tersebar lebih merata. Ira juga telah berubah ke dalam bentuk bulat, yang menjadikan saiz ira dan faktor bentuk yang lebih baik untuk kerja pembentukan-tikso. Kerja-kerja ini menunjukkan bahawa keadaan proses yang optimum untuk pembentukan-tikso D2 AISI ialah 1340°C dan masa yang diambil ialah 5 min. Ia mempunyai faktor bentuk 1.13 dan saiz zarah 51 μm.

 

Kata kunci: AISI D2; evolusi mikrostruktur; mengarahkan sebahagian lebur semula; pembentukan-tikso

REFERENCES

Alfan, A., Omar, M.Z., Syarif, J. & Sajuri, Z. 2010. Direct partial remelting of XW-42 steel in semi-solid zone. Journal of Applied Sciences 10: 1255-1262.

American Society for Testing and Materials. 2004. Standard test methods for determining average grain size. ASTM E 112-96.

Arif, M.A.M., Omar, M.Z., Muhamad, N. & Kapranos, P. 2013. Microstructural evolution of solid-solution-treated Zn-22Al in the semisolid state. Journal of Materials Science & Technology 29: 765-774.

Atkinson, H.V. 2005. Modelling the semisolid processing of metallic alloys. Materials Science 50: 341-412.

Bergsma, S.C., Tolle, M.C., Kassner, M.E., Li, X. & Evangelista, E. 1997. Semi-solid thermal transformations of Al-Si alloys and the resulting mechanical properties. Material Science Eng. 237: 24-34.

Budiman, H., Omar, M.Z., Jalar, A. &. Jaharah, A.G. 2009. Effect of water cooling on the production of Al-Si thixotropic feedstock by cooling slope casting. European Journal of Scientific Research 32: 158-166.

Fan, Z. 2002. Semi-solid metal processing. International Materials Reviews 47: 49-85.

Hirt, G., Bleck, W., Bührig-Polaczek, A., Shimahara, H., Püttgen, W. & Afrath, C. 2006. Semi solid casting and forging of steel. Solid State Phenomena 116-117: 34-43.

Hirt, G., Khizhnyakova, L., Baadjou, R., Knauf, F. & Kopp, R. 2009. Semi-solid forming of aluminium and steel-introduction and overview. In Thixoforming-Semi-Solid Metal Processing, edited by Hirt, G. & Kopp, R. USA: Willey-VCH Verlag GmbH. pp: 1-27.

Legoretta, E.C., Atkinson, H.V. & Jones, H. 2008. Cooling slope casting to obtain thixotropic feedstock II: Observations with A356 alloy. Materials Science 43: 5456-5469.

Mohammed, M.N., Omar, M.Z., Salleh, M.S., Alhawari, K.S. & Kapranos, P. 2013a. Semi-solid metal processing techniques for nondendritic feedstock production. The Scientific World Journal 2013: 752175.

Mohammed, M.N., Omar, M.Z., Salleh, M.S. & Alhawari, K.S. 2013b. Study on thixojoining process using partial remelting method. Advances in Materials Science and Engineering 2013: 251472.

Mohammed, M.N., Omar, M.Z., Syarif, J., Sajuri, Z., Salleh, M.S. & Alhawari, K.S. 2013c. Microstructural evolution during DPRM process of semisolid ledeburitic D2 tool steel. The Scientific World Journal 2013: 828926.

Mohammed, M.N., Omar, M.Z., Salleh, M.S., Zailani, M.A. & Alhawari, K.S. 2012. Joining two metals via partial remelting method. Journal of Asian Scientific Research 2: 724-730.

Omar, M.Z., Alfan, A., Syarif, J. & Atkinson, H.V. 2011a. Microstructural investigations of XW-42 and M2 tool steels in semi-solid zones via direct partial remelting route. Journal of Materials Science 46: 7696-7705.

Omar, M.Z., Atkinson, H.V. & Kapranos, P. 2011b. Thixotropy in semisolid steel slurries under rapid compression. Metallurgical and Materials Transactions A 42: 2807-2819.

Omar, M.Z., Atkinson, H.V., Howe, A.A., Palmiere, E.J., Kapranos, P. & Ghazali, M.J. 2009. Solid-liquid structural break-up in M2 tool steel for semi-solid metal processing. Material Science 44: 869-874.

Salleh, M.S., Omar, M.Z., Syarif, J. & Mohammed, M.N. 2012. Thermodynamic modelling on the mutual effect of copper, manganese and iron addition in Al-Si-Cu for semisolid processing. Journal of Asian Scientific Research 2: 614-619.

Spencer, D.B., Mehrabian, R. & Flemings, M.C. 1972. Rheological behavior of Sn-15 Pct Pb in the crystallization range. Metallurgical and Materials Transactions 3: 1925- 1932.

Vivès, Ch. 1993. Effects of electromagnetic vibrations on the microstructure of continuously cast aluminium alloys. Material Science Eng. 173: 169-172.

 

 

*Corresponding author; email: zaidi@eng.ukm.edu.my

 

 

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