NOKTA DİRENÇ KAYNAĞI İLE BİRLEŞTİRİLEN FARKLI DAYANIM SEVİYELERİNE SAHİP ÇİFT FAZLI ÇELİKLERİN MİKROYAPI VE MEKANİK ÖZELLİKLERİNİN İNCELENMESİ
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Tarih
2023-07
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info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, DP600-DP1000 ve DP600-DP1200 çift fazlı çeliklerin mikroyapı ve mekanik özelliklerini değerlendirmek için nokta direnç kaynaklı birleşimleri gerçekleştirilmiştir. Nokta direnç kaynak işlemleri 7 kA sabit kaynak akımında ve 2, 3, 4, 5, 6 Bar olmak üzere 5 farklı elektrot basıncında uygulanmıştır. Farklı birleşimlerin mikroyapı analizleri, çekirdek çap ölçümleri, çekme-makaslama deneyleri ve sonrasında meydana gelen kırılma tipleri detaylı olarak incelenmiştir. Esas metalden kaynak metaline doğru martenzit hacim oranı artmıştır. Elektrot basıncı arttıkça çekme-makaslama kuvveti her iki birleşim çeşidi için de azalmıştır. Birleşimlerde kırılmalar daha düşük dayanım seviyesine sahip olan DP600 tarafında meydana gelmiştir. Tüm birleşimlerde özellikle otomotiv endüstrisinde tercih edilen düğme tipi kırılma gözlenmiştir.
In this study, joints of Dual Phase Steels which are DP600-DP1000 and DP600-DP1200 was carried out by resistance spot weldings to evaluate microstructure and mechanical properties. Processes of resistance of spot welding was performed 7kA constant welding current and five different electrode pressure (2-6 Bar). Microstructure analysis of different joints, measurement of nugget diameter, tensile shear tests and types of fraction that is took place because of these tests was investigated in detail. Results shows joints of welded consisted of three different region just as base metal, heat-affected zone, weld metal. Volume ratio of martensite was increased from base metal to weld metal. As long as electrode pressure is increased, strength of tensile shear is decreased for both joints types. Fractions in joints was occurred on the side of DP600 which has lower strength than others. In all joints were observed plug type failure especially favored in automotive industry."
In this study, joints of Dual Phase Steels which are DP600-DP1000 and DP600-DP1200 was carried out by resistance spot weldings to evaluate microstructure and mechanical properties. Processes of resistance of spot welding was performed 7kA constant welding current and five different electrode pressure (2-6 Bar). Microstructure analysis of different joints, measurement of nugget diameter, tensile shear tests and types of fraction that is took place because of these tests was investigated in detail. Results shows joints of welded consisted of three different region just as base metal, heat-affected zone, weld metal. Volume ratio of martensite was increased from base metal to weld metal. As long as electrode pressure is increased, strength of tensile shear is decreased for both joints types. Fractions in joints was occurred on the side of DP600 which has lower strength than others. In all joints were observed plug type failure especially favored in automotive industry."
Açıklama
Anahtar Kelimeler
Nokta direnç kaynağı, Çift fazlı çelik, Mikroyapı, Çekme-makaslama kuvveti, Düğme tipi kırılma, Resistance spot welding, Dual phase steel, Microstructure, Tensile shear
