Publication: Farklı koşullarda dövülmüş kurşunsuz pirinç malzemelerin işlenebilirliğinin incelenmesi
Abstract
Sıhhi tesisatta kullanılan ürünlerin kurşunsuz pirinçten imal edilmesi zorunluluğu son yıllarda bu malzemeden imal edilen ürünlere olan talepte çok ciddi artışa sebep olmuştur. Kurşunlu pirinçlerle kıyaslandığında, uzun ve sürekli talaş, çapak, takımda yığma ağız, kabul edilemez yüzey kalitesi sorunu gibi sebeplerden dolayı talaşlı imalatı hayli zorlaşmaktadır. Bu tezde, kurşunsuz pirinç malzemelerin mikroyapısal ve mekanik özelliklerinin kontrolü ile bahsi geçen talaşlı imalat sorunlarını minimize eden birim zamandaki üretim hacmini arttıracak talaşlı imalat sürecinin geliştirilmesine yönelik çalışmalar gerçekleştirilmiştir.Bu tez kapsamında, Kurşunsuz Pirinç Malzemelerin, sıcak dövme sürecindeki ; Dövülecek malzemenin bakır oranı, dövme öncesi numune sıcaklığı, dövme sonrası kriyojenik soğutma yöntemi, tavlama süresi girdi parametrelerinin malzemenin mikroyapısal ve mekanik özellikleri üzerine etkisi incelenerek iyi derecede talaş kırılabilirliğine sahip olan Kurşunlu Pirinç Malzemelerin işlenebilirlik performansına yakın ve yüksek performanslı talaşlı imalat süreci elde edilmesi üzerine çalışmalar gerçekleştirilmiştir. Faz oranı, tane boyutu gibi mikroyapısal özellikler ve mikrosertlik, kırılma enerjisi gibi mekanik özelliklerin belirlenmesi için test ve analizler gerçekleştirilmiştir. Dövme işlemindeki parametrelerin belirlenmesi sonrasında talaşlı imalat testleri delik delme operasyonu olarak gerçekleştirilmiştir. Talaşlı imalat testleri sonrasında kesme kuvvetleri, yüzey pürüzlülüğü, boyutsal doğruluk analizleri gerçekleştirilmiştir.
The necessity of manufacturing products used in sanitary systems from lead-free brass has led to a significant increase in the demand for products made of this material in recent years. Compared to leaded brasses, machining becomes very difficult due to reasons such as long and continuous chips, burrs, built up edge in the tool, and unacceptable surface quality problems. In this thesis, studies have been carried out to develop the machining process that will increase the production volume per unit time, which minimizes the mentioned machining problems by controlling the microstructural and mechanical properties of lead-free brass materials.Within the scope of this thesis, in the hot forging process of Lead-Free Brass Materials; Studies on obtaining a high performance machining process close to the machinability performance of Lead Brass Materials with good chip breakability by examining the effect of input parameters of the copper ratio of the forged material,test sample temperature before forging, cryogenic cooling method after forging, annealing time on the microstructural and mechanical properties of the material. Tests and analyzes were carried out to determine microstructural properties such as phase ratio, grain size and mechanical properties such as microhardness and fracture energy. After the determination of the parameters in the forging process, the machining tests were carried out as a hole drilling operation. After the machining tests, cutting forces, surface roughness and dimensional accuracy analyzes were carried out.
The necessity of manufacturing products used in sanitary systems from lead-free brass has led to a significant increase in the demand for products made of this material in recent years. Compared to leaded brasses, machining becomes very difficult due to reasons such as long and continuous chips, burrs, built up edge in the tool, and unacceptable surface quality problems. In this thesis, studies have been carried out to develop the machining process that will increase the production volume per unit time, which minimizes the mentioned machining problems by controlling the microstructural and mechanical properties of lead-free brass materials.Within the scope of this thesis, in the hot forging process of Lead-Free Brass Materials; Studies on obtaining a high performance machining process close to the machinability performance of Lead Brass Materials with good chip breakability by examining the effect of input parameters of the copper ratio of the forged material,test sample temperature before forging, cryogenic cooling method after forging, annealing time on the microstructural and mechanical properties of the material. Tests and analyzes were carried out to determine microstructural properties such as phase ratio, grain size and mechanical properties such as microhardness and fracture energy. After the determination of the parameters in the forging process, the machining tests were carried out as a hole drilling operation. After the machining tests, cutting forces, surface roughness and dimensional accuracy analyzes were carried out.