INVESTIGATION OF THE MICROSTRUCTURAL AND MECHANICAL PROPERTIES OF EQUAL CHANNEL ANGULAR PRESSED (ECAPED) SHIP BUILDING STEEL

Abstract

Low-medium strength steels are used by increasing their thickness in parts where high strength is required on ships due to the low weldability and formability of high-strength steels. The use of thicker plates brings about a significant increase in the ship’s weight and their fuel consumption as expected. So, it is very important to improve the strength of low-medium strength shipbuilding steels by applying severe plastic deformation methods or heat treatments. Grain refinement via severe plastic deformation (SPD) seems to be an essential strengthening mechanism without changing the chemical composition of metallic materials. Among SPD methods, equal channel angular pressing (ECAP) is one of the most commonly used one due to its high grain refinement capacity. When the literature is examined, it is clearly seen that ECAP is not applied to any shipbuilding steel before. Therefore, in this study, one pass ECAP at 300 0C to low-medium strength shipbuilding steel (Grade A) which has intensively used in the shipbuilding industry and the changes in the microstructural and mechanical properties of steel after ECAP were investigated. After investigations, it was determined that the average grain size after ECAP decreased from 25 μm (base material) to 7 μm and as a result of this, hardness and strength values increased significantly compared to the base material. On the other hand, wear and formability tests were applied after and before ECAP and it was determined that while a slight improvement was obtained in wear behavior, formability behavior deteriorated after ECAP.

Keywords

• Equal Channel Angular,Pressing,Shipbuilding,Low Carbon Steel,Microstructure,Mechanical Properties

EŞ KANALLI AÇISAL PRESLEME (EKAP) UYGULANAN GEMİ İNŞA ÇELİĞİNİN İÇYAPI VE MEKANİK ÖZELLİKLERİNİN İNCELENMESİ

Abstract

Yüksek mukavemetli çeliklerin düşük kaynak edilebilirlik ve şekillendirilebilmeleri nedeniyle, gemilerde yüksek dayanım istenen kısımlarda düşük-orta mukavemetli çelikler kalınlıkları arttırılarak kullanılmaktadır. Daha kalın sacların kullanılması beraberinde ağırlığın ve yakıt tüketiminin önemli ölçüde artmasını getirmektedir. Bu bağlamda düşük-orta mukavemetli gemi imalat çeliklerinin aşırı plastik deformasyon yöntemleri veya ısıl işlemler uygulanarak dayanımlarının geliştirilmesi oldukça önemlidir. Aşırı plastik deformasyon (APD) yöntemleri ile malzemenin kimyasal bileşiminde herhangi bir değişiklik yapmadan tane boyutunu küçülterek malzemenin mukavemetini arttırmak son dönemlerde sıklıkla kullanılmaktadır. APD yöntemleri arasında eş kanallı açısal presleme (EKAP) yöntemi yüksek oranda tane inceltme ve mukavemet arttırma özelliği bakımından öne çıkmaktadır. Literatür incelendiğinde EKAP yönteminin herhangi bir gemi inşa çeliğine uygulamasının olmadığı açıkca görülmektedir. Bu yüzden yapılan çalışmada gemi inşaatından yoğun bir kullanıma sahip düşük-orta mukavemetli Grade A gemi inşa çeliğine 300 0C’de tek paso EKAP uygulanmış ve EKAP sonrası çelikteki içyapısal ve mekanik özelliklerinin değişimleri incelenmiştir. İncelemeler sonucunda EKAP sonrası ortalama tane boyutunun 25 μm seviyesinden 7 μm seviyesine indiği ve tane boyutunda meydana gelen bu azalmanın sonucu olarak sertlik ve mukavemet değerlerinin ana yapıya göre önemli oranda arttığı belirlenmiştir. Öte yandan EKAP sonrası numunelere aşınma ve şekil verilebilirlik deneyleri de uygulanmış ve aşınma davranışının bir miktar iyileştiği şekil verilebilirliğin ise EKAP sonrası kötüleştiği belirlenmiştir.

Keywords

• Eş Kanallı Açısal Presleme,Gemi İnşaatı,Düşük Karbonlu Çelik,İçyapı,Mekanik Özellik

Thanks

Çalışma kapsamında laboratuvar imkânlarının kullanılması noktasındaki katkılarından ötürü Karadeniz Teknik Üniversitesi Makine Mühendisliği Bölümü Öğretim Üyesi Prof. Dr. Gençağa PÜRÇEK’e teşekkürü bir borç bilirim.

References

1. Aldajah, S.H., Ajayi, O.O., Fenske, G.R., David, S., 2009. Effect of friction stir processing on the tribological performance of high carbon steel. Wear, 267(1–4), 350-355.
2. Becker, R., 1998. Effects of strain localization on surface roughening during sheet forming. Acta Materialia, 46(4), 1385-1401.
3. Bhadeshia, H. ve Honeycombe, R., 2011. Steels: Microstructure and Properties, Elsevier Science,.
4. Cheng, S., Spencer, J.A., Milligan, W.W., 2003. Strength and tension/compression asymmetry in nanostructured and ultrafine-grain metals. Acta Materialia, 51(15), 4505-4518.
5. Demirtas, M., Kawasaki, M., Yanar, H., Purcek, G., 2018. High temperature superplasticity and deformation behavior of naturally aged Zn-Al alloys with different phase compositions. Materials Science and Engineering: A, 730, 73-83.
6. Demirtas, M., Purcek, G., Yanar, H., Zhang, Z.J., Zhang, Z.F., 2015. Effect of equal-channel angular pressing on room temperature superplasticity of quasi-single phase Zn–0.3Al alloy. Materials Science and Engineering: A, 644, 17-24.
7. Demirtaş, M., 2017. Çinko-Esaslı Süperplastik Alaşımların Geliştirilmesi ve Yapısal, Mekanik ve Titreşim Sönümleme Davranışlarının İncelenmesi. Trabzon, Karadeniz Teknik Üniversitesi.
8. Dobatkin, S.V., Skrotzki, W., Rybalchenko, O.V., Terent’ev, V.F., Belyakov, A.N., Prosvirnin, D.V., Raab, G.I., Zolotarev, E.V., 2018. Structural changes in metastable austenitic steel during equal channel angular pressing and subsequent cyclic deformation. Materials Science and Engineering: A, 723, 141-147.

9. Ebrahimi, M., Attarilar, S., Shaeri, M.H., Gode, C., Armoon, H., Djavanroodi, F., 2019. An investigation into the effect of alloying elements on corrosion behavior of severely deformed Cu-Sn alloys by equal channel angular pressing. Archives of Civil and Mechanical Engineering, 19(3), 842-850.
10. Eyres, D.J., 2001. Ship Construction, Butterworth-Heinemann.
11. Furukawa, M., Horita, Z., Nemoto, M., Langdon, T.G., 2001. Review: Processing of metals by equal-channel angular pressing. Journal of Materials Science, 36(12), 2835-2843.
12. Gholinia, A., Prangnell, P.B., Markushev, M.V., 2000. The effect of strain path on the development of deformation structures in severely deformed aluminium alloys processed by ECAE. Acta Materialia, 48(5), 1115-1130.
13. Hayat, F., Uzun, H., 2011. Effect of Heat Treatment on Microstructure, Mechanical Properties and Fracture Behaviour of Ship and Dual Phase Steels. Journal of Iron and Steel Research International, 18(8), 65-72.
14. Horikiri, G., Kitazumi, T., Natori, K., Tanaka, T., 2017. Improvement in mechanical properties of semi-solid AA7075 aluminum alloys by Equal-Channel Angular Pressing. Procedia Engineering, 207, 1451-1456.
15. Huang, S.J., Semenov, V.I., Shuster, L.S., Lin, P.C., 2011. Tribological properties of the low-carbon steels with different micro-structure processed by heat treatment and severe plastic deformation. Wear, 271(5), 705-711.
16. Islamgaliev, R.K., Nikitina, M.A., Ganeev, A.V., Sitdikov, V.D., 2019. Strengthening mechanisms in ultrafine-grained ferritic/martensitic steel produced by equal channel angular pressing. Materials Science and Engineering: A, 744, 163-170.
17. Iwahashi, Y., Horita, Z., Nemoto, M., Langdon, T.G., 1998. The process of grain refinement in equal-channel angular pressing. Acta Materialia, 46(9), 3317-3331.
18. Kim, H.S., Ryu, W.S., Janecek, M., Baik, S.C., Estrin, Y., 2005. Effect of Equal Channel Angular Pressing on Microstructure and Mechanical Properties of IF Steel. Advanced Engineering Materials, 7(1‐2), 43-46.
19. Klepaczko, J.R., Rusinek, A., Rodríguez-Martínez, J.A., Pęcherski, R.B. ve Arias, A., 2009. Modelling of thermo-viscoplastic behaviour of DH-36 and Weldox 460-E structural steels at wide ranges of strain rates and temperatures, comparison of constitutive relations for impact problems. Mechanics of Materials, 41(5), 599-621.
20. Langdon, T.G., 2007. The principles of grain refinement in equal-channel angular pressing. Materials Science and Engineering: A, 462(1), 3-11.
21. Levin, Z.S., Brady, B.G., Foley, D.C., Hartwig, K.T., 2019. Recrystallization behavior of tungsten processed by equal channel angular extrusion at low homologues temperature: Microstructure, hardness, and texture. International Journal of Refractory Metals and Hard Materials, accepted manuscript.
22. Li, Y., Pang, Ng. H., Jung, H.D., Kim, H.E., Estrin, Y., 2014. Enhancement of mechanical properties of grade 4 titanium by equal channel angular pressing with billet encapsulation. Materials Letters, 114, 144-147.
23. Maier, G.G., Astafurova, E.G., Maier, H.J., Naydenkin, E.V., Raab, G.I., Odessky, P.D., Dobatkin, S.V., 2013. Annealing behavior of ultrafine grained structure in low-carbon steel produced by equal channel angular pressing. Materials Science and Engineering: A, 581, 104-107.
24. Niendorf, T., Canadinc, D., Maier, H.J., Karaman, I., Sutter, S.G., 2006. On the fatigue behavior of ultrafine-grained interstitial-free steel. International Journal of Materials Research, 97(10), 1328-1336.
25. Saray, O., Purcek, G., Karaman, I., Maier, H.J., 2013. Formability of Ultrafine-Grained Interstitial-Free Steels. Metallurgical and Materials Transactions A, 44(9), 4194-4206.
26. Saray, O., Purcek, G., Karaman, I., Maier, H.J., 2014. Improvement of formability of ultrafine-grained materials by post-SPD annealing. Materials Science and Engineering: A,. 619, 119-128.
27. Saray, O., Purcek, G., Karaman, I., Neindorf, T., Maier, H.J., 2011. Equal-channel angular sheet extrusion of interstitial-free (IF) steel: Microstructural evolution and mechanical properties. Materials Science and Engineering: A, 528(21), 6573-6583.
28. Segal, V.M., 1999. Equal channel angular extrusion: from macromechanics to structure formation. Materials Science and Engineering: A, 271(1), 322-333.
29. Sekban, D.M., Aktarer, S.M., Xue, P., Ma, Z.Y., Purcek, G., 2016. Impact toughness of friction stir processed low carbon steel used in shipbuilding. Materials Science and Engineering: A, 672, 40-48.
30. Sekban, D.M., Akterer, S.M., Saray, O., Ma, Z.Y., Purcek, G., 2018. Formability of friction stir processed low carbon steels used in shipbuilding. Journal of Materials Science & Technology, 34(1), 237-244.
31. Shaeri, M.H., Shaeri, M., Salehi, M.T., Seyyedein, S.H., Abutalebi, M.R., 2015. Effect of equal channel angular pressing on aging treatment of Al-7075 alloy. Progress in Natural Science: Materials International, 25(2), 159-168.
32. Smirnov, I., Konstantinov, A., 2018. Influence of ultrafine-grained structure produced by equal-channel angular pressing on the dynamic response of pure copper. Procedia Structural Integrity, 13, 1336-1341.
33. Suresh, M., Sharma, A., More, A.M., Kalsar, R., Bisht, A., Nayan, N., Suwas, S., 2019. Effect of equal channel angular pressing (ECAP) on the evolution of texture, microstructure and mechanical properties in the Al-Cu-Li alloy AA2195. Journal of Alloys and Compounds, 785, 972-983.
34. Valiev, R.Z., Islamgaliev, R.K., Alexandrov, I.V., 2000. Bulk nanostructured materials from severe plastic deformation. Progress in Materials Science, 45(2), 103-189.
35. Valiev, R.Z., Langdon, T.G., 2006. Principles of equal-channel angular pressing as a processing tool for grain refinement. Progress in Materials Science, 51(7), 881-981.
36. Wouters, O., Vellinga, W.P., Tijum, R.V., de Hosson, J.T.M., 2005. On the evolution of surface roughness during deformation of polycrystalline aluminum alloys. Acta Materialia, 53(15), 4043-4050.
37. Yanxia, G., Aibin, M., Jinghua, J., Dan, S., 2017. Research Progress of Ultrafine-Grained Pure Titanium Produced by Equal-Channel Angular Pressing. Rare Metal Materials and Engineering, 46(12), 3639-3644.
38. Yasavol, N., Ramalho, A., 2015. Wear properties of friction stir processed AISI D2 tool steel. Tribology International, 91, 177-183.
39. Zhao, Y., Topping, T., Li, Y., Lavernia, E.J., 2011. Strength and Ductility of Bi-Modal Cu. Advanced Engineering Materials, 13(9), 865-871.