Alaşımsız ve düşük alaşımlı çeliklerde küreselleştirme ısıl işleminin optimizasyonu ve hassas kesme işlemine etkisi

Abstract

AISI 4140 is a tempered steel with high strength and ductility, which can be hardened as a result of heat treatment applications. Due to its structural features, it finds a wide place in the machinery manufacturing, automotive, defense and aerospace industries. AISI 6150 steel grade is spring steel used in the machinery manufacturing industry, especially in the automotive industry, due to its features such as high wear resistance, strength and impact toughness. AISI 1045 and AISI 1070 steel grades are in the group of medium and high carbon spring steels that do not contain alloying elements. Due to their high strength and hardness properties, as well as their low cost, their use in similar sectors has become widespread over time. The heat treatment capabilities of these materials are frequently used during the production of parts for the automotive sector, which is among the common areas of use of the steel grades used in the study. The complexity of the part geometry, which is especially needed in the automotive industry, causes a decrease in product quality. These high strength and brittle structures of steels play a restrictive role in the shaping of parts. Other parameters that affect the result of the sheet metal forming process are the die geometry and the pressing process. With the development of today's technology in the machinery manufacturing sector, the traditional cutting processes have started to be replaced by the fine blanking process for the production of parts with high surface quality and dimensional accuracy. Due to the fact that the molds and hydraulic presses used in the fine blanking process create systems that operate with very low tolerances and high precision, very high efficiency can be achieved. For this reason, various heat treatment methods have been developed to improve material properties in order to increase product quality. After the traditional cutting process, fracture surface and shear surface are observed in the edge morphology of the piece. Fracture area has a rough structure because of formed as a result of tearing. It is known that the mechanical performance of the material decreases because these indentations and protrusions in the rough structure. Material tearing is affected by die design, punch geometry, cutting speed, and material microstructure. Preferred the fine blanking process, it is aimed to obtain an edge morphology with the entire sheared surface. After this cutting, in which burr, tearing, roll over and fracture penetration is minimal, the surface of the piece is formed higher quality. In order to increase the formability of the materials, it is necessary to increase the ductility and decrease the brittleness.