Investigating the effect of tungsten and heat treatment on microstructure and wear behavior of Ni-hard 4 cast iron

Document Type : Research Paper

Authors

• A. Karimi Taghanaki
• T. Dallali Isfahani
• H. Ghayour H. Ghayour
• F. Shah mohammadian

Abstract

      Wear is a major cause of damage occurring in workpieces and industrial machins, especially in construction and mining industry.  One of the most common and widely used alloys in the above-mentioned industries is Ni-hard 4 cast iron. In the present study, the addition of tungsten to Ni-hard 4 cast iron and its effect on the morphology, structure and wear resistance have been investigated. For this purpose, samples containing of 0, 0.3, 0.7 and 1.1 wt % tungsten were prepared by casting and then heat treatment was applied. After the heat treatment the effect of tungsten on the structure and wear behavior of different alloys in the as-cast and heat treated samples were examined. The structures of the samples were studied by optical microscope and scanning electron microscope furthermore EDS analysis was used to determine the distribution of chromium and tungsten in the different phases in the microstructure. The results showed that the tungsten was solved in the existing phases present in Ni-hard 4 cast iron and fishbone-type and spongy tungsten carbides were formed due to the long-range segregation of tungsten during solidification and also due to the eutectic reaction.  Furthermore by applying heat treatment the tungsten carbides dissolved in the eutectic carbides and in various parts of the matrix had a higher potential for a more homogeneous nucleation of secondary carbides. In addition the distribution of the secondary carbide precipitations becomes finer and more uniform. The area fraction of the carbides increased by 4.23% and the average diameter of the carbides decreased from 47.2 to 20.6 μm. As a result the abrasion properties improves.

Keywords

• tungsten
• Ni-hard 4 cast iron
• casting
• Wear
• Heat Treatment

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References

References:

 

1-J. Gordan, "Development of abrasion-resistant Nickel-containing alloy white irons of high-hardness", American Foundrymens Society,11, pp. 1-21, 1988.

2-L. Jinzhu and M. Yongfa, "Wear resistance of ni-hard 4 and high-chromium cast iron re-evaluated",  ASTM international, Wear, 186, pp. 37 -40, 1986.

3-Standard ASTM A532-standard specification for abrasion resistant cast iron.     

 

4- م. ع. گلعذار، "اصول کاربرد عملیات حرارتی فولاد ها و
چدن ها  "، اتشارات دانشگاه صنعتی اصفهان، ص 396، 1367.

5- June-Tongxi,Qing-Dezhon, Shi-Hui and Guang-Shun-Song; " Influence of retained austenite on the wear resistance of high-chromium cast iron under various impact loads", Wear, 162-164, 1993.

6-F.Maratray and A.Poulation, "Austenite retention in high-chromium white iron", AFS Transactions, 895-803, 1982.

7-R.B.Gundlach, "Microstructure, hardness and abrasion resistance of as-cast 17.5% chromium white cast iron", AFS Transactions, 309-316, 1974.

8-J.M.Tong, Y.Z.Zhou, T.Y.Shen and H.J.Deng, "The influence of retained austenite in high chromium cast iron on impact-abrasion wear", Wear, 135, 217-226, 1990.

9-I.R.Sare and B.K.Arnold, "The effect of heat treatment on the gouging abrasion resistance of alloy white cast irons", Metallurgical Transactions A, 26A, 357-370, 1995.

10-C.P.Tabrett and I.R.Sare, "Effect of high temperature and sub-ambient treatments on the matrix structure and abrasion resistance of a high-chromium white iron", Scripta Materialia, 38, 1747-1753, 1998.

11-J.T.H.Pearce, "High chromium cast Irons to resist abrasive wear", Technical paper, Foundryman, 156-166, April 2002.

12-. Jinzhu and M. Yongfa, "Wear resistance of Ni-hard 4 high-chromium cast iron re-evaluated",  ASTM international, Wear, 186, pp. 37 -40, 1986.

13-L.Jinzhu and M.Yongfa, "Development of abrasion-resistant Ni-hard 4 cast irons", Wear, 162, pp. 883-836, 1993.

14-م.  ب. علمدارلو ،و.جواهری، "تاثیر افزودن تیتانیوم بر مورفولوژی کاربید M7C3 در چدن Ni-hard4،"دومین همایش صنایع معدنی،کرمان، پژوهشکده صنایع معادن دانشگاه شهید باهنر کرمان.

15-A. Bedolla and A. Jacuinde, "Effect of titanium on the as-cast microstructure of a 16% chromium white iron",Materials science and engineering A, 398,pp.297-308, 2005.

16-S.H. Mousavi, A. Bahrami and P. Davami, "Effects of tungsten on erosion–corrosion behavior of high chromium white cast iron", Materials Science and Engineering A, 454–455, 2007.

17-ع.  شفاعتی، ف. خمامی زاده، "بررسی ساختاری چدن‌های سفید پرکروم حاوی تنگستن"، دومین همایش مشترک انجمن مهندسین متالورژی ایران وجامعه ریختگران ایران، 1-4، 1387.

18-Y.Lv. Yufu Sun , J. Zhao and J. Sh. Sumeng Hu, "Effect of tungsten on microstructure and properties of high chromium cast iron", Materials and Design, 39, pp.303–308, 2012.

19-Meesoft, Image Analyzer, Version 1.35, 2013.

20-D. A. Rigney and W. A. Glaeser, source book on wear control technology, American society for metals, 1978.

21-R. G. Bayer, mechanical wear fundamental and testing, Mahrcell dekkr, 2004.

22-آ، هاچینگر، ر، بخشی،" اصطکاک وسایش مواد مهندسی" دانشگاه صنعتی مالک اشتر،1383.

23-ا، رنجبر، ع، جعفری، ک، جانقریان، ع، کارگر،  "بررسی فرایند سایش و خوردگی سایشی چدن‌های سفید  Ni-hard2،Ni-hard1 و چدن سفید پر کروم Cr%27 و مقایسه‌ی این دو فرایند"، چهارمین کنگره سالانه انجمن مهندسین ایران، ص 25-27، 1379.