Mehmet ERDOĞAN, Ahmet GÜRAL, İhsan KORKUT, Ulvi ŞEKER

Çift fazlı çeliklerde martensit hacim oranı ve parçacık boyutunun kesici uçta aşınma ve sıvanma (BUE) oluşma eğilimleri üzerine etkileri

Bu çalışmada, AISI-SAE 8620 çeliği ve bu çelikten üretilen farklı martensit hacim oranı (MHO) ve martensit parçacık boyutuna (MPB' na) (kaba, orta ve ince) sahip çift fazlı çeliklerin (ÇFÇ' in) işlenmesinde kullanılan kesici uçlar üzerinde aşınma ve sıvanma (built-up edge;BUE) oluşma eğilimleri ve bunların yüzey pürüzlülüğüne etkileri farklı kesme hızlarında incelenmiştir. ÇFÇ' de BUE oluşma eğilimi, ferrit+perlit mikro yapılı çeliklerde (FPÇ' de) BUE oluşma eğilimine göre daha az gerçekleşmiştir. Genellikle, ÇFÇ' de, BUE oluşma eğilimi, MHO ve kesme hızının artırılmasıyla ve MPB'nün inceltilmesiyle minimize edilmiştir. Bu eğilim, aynı zamanda (FPÇ'in) işlenmesinde kesme hızının artırılması ile ve perlit tane boyutunun inceltilmesi ile de minimize edilmiştir. Yüksek kesme hızlarında kaba MPB' na sahip ÇFÇ' in işlenmesi ile kesici uç üzerinde çentiklenme tipi aşınma eğilimi gözlenmiştir. İnce MPB' na sahip ÇFÇ' in işlenmesinde yüksek kesme hızlarında kesici uç üzerinde sıvanma ve aşınma eğilimi gözlenmemiştir.

The effects of martensite volume fractions and particle sizes in dual phase steels on the wear and built-up edge formation tendencies on cutting edges radius

In this work wear and built-up edge (BUE) formation tendency on the cutting edges radius and their effect on surface roughness öf as received AISI-SAE 8620 steel and dual phase steel (DPS) having different martensite volume fraction (MVF) and martensite partide sizes (MPS) (coarse, medium and fine) produced from AISI-SAE 8620 steel were exanıined at different cutting speeds. BUE forrnation tendency in DPS was less than BUE formation tendency in steels composed of ferrite plus pearlite (FPS). Generally, BUE formation tendency with DPSs was minimised with increasing MVF and cutting speeds and with decreasing MPS. This tendency in FPS was also minimised with increasing cutting speeds and with fine pearlite structure. At high cutting speeds chipping type wear was observed on the cutting edge with machining DPS having coarse MPS. Wear and BUE formation tendencies were not observed with machining steels having fine MPS at high cutting speeds.

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