Effect of Soaking Time on the Mechanical Properties of Annealed Cold-Drawn Low Carbon Steel (original) (raw)
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Influence of Degree of Cold-Drawing on the Mechanical Properties of Low Carbon Steel
Low carbon steel metal is used for the manufacture of nails. Steel wire with <0.3% C content is cold-drawn through a series of drawing dies to reduce the diameter of the wire to the required diameter of the nails. A 0.12%w C steel wire cold drawn progressively by 20%, 25%, 40% and 50% was investigated. The influence of the degree of cold drawing on the mechanical properties of the carbon steel material were studied using the tensile test, impact test and hardness test experiments in order to replicate the service condition of the nails. The tensile test was done on a Montanso® tensome- ter to investigate the yield strength and the tensile strength of the material as the degree of deformation increases. An Izod test was used to determine the impact toughness of the steel using the Hounsfield impact machine and the hardness numbers were obtained for the different degrees of drawn deformation of the steel on the Brinnel tester. The study used the stress-strain relationship of the tensile test experiment to study the effect of the degree of cold-drawing deformation on the yield strength and tensile strength properties of the low carbon steel. The yield strength of the material was ob- served to reduce with increasing degree of cold-drawing, an indication of reduction in the ductility and the tensile strength of the material reduced with increasing degree of cold-drawn deformation. The ability of the material to resist impact loads when nails are hammered reduced with increasing degree of drawn deformation as a result of strain hardening of the material after the drawing operation. However the resilience of the material to further cold drawn deformation increased with increasing degree of deformation as evident in the Brinnel hardness number which in- creases with the degree of drawing deformation. This is an indication of the material’s approach to brittleness as the degree of drawn deformation increases.
Drawn low carbon steel is characterized by brittle fracture. These defects are associated with the poor ductility and high strain hardening due to the cold work. There is a need therefore to determine optimum heat treatment parameters that could ensure improved toughness and ductility. Determining the optimum annealing parameters ensures valued recrys-tallization and also minimizes grain growth that could be detrimental to the resulting product. 40% and 55% cold drawn steels were annealed at temperatures 500°C to 650°C at intervals of 50°C and soaked for 10 to 60 minutes at interval of 10 minutes to identify the temperature range and soaking time where optimum combination of properties could be ob-tained. Tensile test and impact toughness experiments were done to determine the required properties of the steel. Po-lynomial regression analysis was used to fit the properties relationship with soaking time and temperatures and the clas-sical optimization technique was used to determine the minimum soaking time and temperature required for improved properties of the steel. Annealing treatment at 588°C for 11 minutes at grain size of 44.7 m can be considered to be the optimum annealing treatment for the 40% cold drawn 0.12 wt% C steel and 539°C for 17 minutes at grain size of 19.5 m for the 55% cold drawn 0.12 wt% C steel.
The aim of this work is to determine the mechanical properties of cold drawn low carbon steel subjected to full annealing. The specimens were slowly heated up to a temperature of 900°C followed by soaking treatment of 60 minutes under this temperature in a muffle furnace. Tensile, charpy and Brinnel hardness tests were conducted to determine the yield strengths, tensile strengths, impact strengths, and hardness of the annealed steel. The yield strength, tensile strength, hardness and toughness of the nail are greater in the non-treated nails when compared to the fully annealed nails at 60 minutes soaking time. The microstructure analysis showed that rate of grain nucleation and recrystallization increased with increasing degree of cold-drawn deformation. Grain growth was observed at higher degree of deformation leading into reduction in the mechanical properties of the material. I t i s e v i d e n t f r om t h e r e s u l t i n g me c h a n i c a l p r o p e r t i e s o f t h e n a i l s a n d t h e mi c r o s t r u c t u r e a n a l y s i s t h a t d e s i r e d p r o p e r t i e s o f t h e n a i l s c o u l d b e o b t a i n e d b y c o n t r o l l i n g t h e mic r o s t r u c t u r e e v o l u t i o n o f t h e l ow c a r b o n s t e e l i n a n n e a l i n g
Mechanical Properties of Cold-Drawn Low Carbon Steel for Nail Manufacture: Experimental Observation
The objective of this study is to investigate the influence of service situation on the mechanical properties of plain nails manufactured from low carbon steel. The influence of the degree of cold drawing on the mechanical properties and strain hardening of the material is investigated by tensile test experimentation. The stress-strain relationships of the cold-drawn low carbon steel were investigated over the 20, 25, 40 and 55% degree of drawn deformation for the manufacture of 4, 3, 2½ and 2 inches nails, respectively. The true stressstrain curves were analyzed to obtain the yield strength and tensile strength of the cold drawn steel. It is shown that the yield strength, tensile strength, hardness and toughness of the low carbon steel reduce with increasing degree of cold-drawn deformation. The micrographs of the deformed samples obtained using optical microscope shows that the grain structure elongates in the direction of the drawing operation and misorientation of the grains set in at 40 and 55% degree of deformation. The difference in yield strength was attributed to the strain hardening, resulting from the different degrees of drawn deformation.
1.0 Introduction Plain Carbon Steels are widely used for many industrial applications and manufacturing on account of their low cost and ease of fabrication. In general, plain carbon steels are classified based on their carbon content, Steels with carbon content varying from 0.3% to 0.6% are classified as medium carbon, while those with carbon content less than 0.25% are termed low carbon. Those with high carbon content in the range 0.65-1.5% are classified as high carbon steels. Low carbon steel has attracted a lot of research around the globe due to its numerous industrial applications. In industries, cold rolling is largely responsible for structural changes in engineering materials which often result in improved mechanical properties due to gradual extension of grains in the direction of the principal deformation stress with no recrystallization occurring. A Low Carbon Steel subjected to intercritical annealing at 850oC exhibited a dual phase microstructure consisting of ferrite martensite and presented excellent mechanical properties in term of hardness, strength and elongation (Phoumiphon et al., 2016). To further enhance the mechanical properties of engineering materials, heat treatment operation is carried out on low carbon steels to obtain desirable mechanical properties like hardness; toughness; ductility; strength. Low carbon steel is the most common form of steel as its price is relatively low while it provides material properties that are acceptable for many applications. LCS has a ARTICLE INFORMATION ABSTRACT This study investigated the effect of deformation by cold rolling and stress relief anneal on the mechanical and structural properties of low carbon steel. The as-received steel samples were cold rolled at 20%-40 % degrees of deformation using Buhler rolling machine in Metallurgical and Materials engineering department University of Lagos, Nigeria. Additionally, some of the cold rolled samples were annealed at a temperature of 650°C and soaked for 1 hour in a muffle furnace. The results revealed that the ultimate tensile strength (UTS), percent elongation, hardness and impact strength of the cold rolled low carbon steel improved significantly after stress relief anneal due to the elimination of induced strain hardening caused by cold rolling. The micrographs show that cold rolled + stress relief anneal caused significant recrystallization of ferrite-austenite phase to refine martensite with reduction of dislocations. Therefore, the low carbon steel can be used effectively for structural purposes in machines and equipment.
This work studied the effect of grain size evolution of cold drawn 0.12wt% C steel subjected to process annealing on tensile behavior. 20%, 25%, 40% and 55% cold drawn 0.12wt% C steel were subjected to annealing comprising of slow heating-up to various temperature ranging from 500oC to 700oC at interval of 50oC followed by soaking treatment for 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes under each of the temperature in a muffle furnace. These samples were submitted tooptical microscopy analysis and to tensile test. After annealing at 650oC and soaked for 10 minutes, the dislocation defects were annihilated in the 25% cold drawn samples. Grain coarsening is observed for the annealed steel at soaking time of 20 minutes to 30 minutes after which grain growth commenced at annealing temperature above 650oC at soaking time of 40 minutes for the 25%, 40% and 55% cold drawn samples. Fine grains of the microstructure were observed for all the annealed samples between the temperature range 500 o C-650 o C.The yield strength of the annealed samples increases compared to the non-treated samples thus improving the ductility of the steel. A better improvement of the yield strength is observed for the annealing temperature of 500 o C and 550 o C at soaking time of 10 minutes and 30 minutes for all the cold drawn samples except for the annealed 25% cold drawn steel whose yield strength is below the yield strength of the non-treated samples.
The effect of heat treatment on the hardness and impact properties of medium carbon steel
IOP Conference Series: Materials Science and Engineering, 2016
This paper covers the effect of heat treatment on the mechanical properties of medium carbon steel. The main objective of this project is to investigate the hardness and impact properties of medium carbon steel treated at different heat treatment processes. Three types of heat treatment were performed in this project which are annealing, quenching and tempering. During annealing process, the specimens were heated at 900 o C and soaked for 1 hour in the furnace. The specimens were then quenched in a medium of water and open air, respectively. The treatment was followed by tempering processes which were done at 300 o C, 450 o C, and 600 o C with a soaking time of 2 hours for each temperature. After the heat treatment process completed, Rockwell hardness test and Charpy impact test were performed. The results collected from the Rockwell hardness test and Charpy impact test on the samples after quenching and tempering were compared and analysed. The fractured surfaces of the samples were also been examined by using Scanning Electron Microscope. It was observed that different heat treatment processes gave different hardness value and impact property to the steel. The specimen with the highest hardness was found in samples quenched in water. Besides, the microstructure obtained after tempering provided a good combination of mechanical properties due to the process reduce brittleness by increasing ductility and toughness.
Effect of Heat Treatment Parameters on Mechanical Properties of Medium Carbon Steel
Mechanics and Mechanical Engineering, 2018
Engineering materials, mostly steel, are heat treated under controlled sequence of heating and cooling to alter their physical and mechanical properties to meet desired engineering applications. This paper presents a study of the influence of austenitization temperature, cooling rate, holding time and heating rate during the heat treatment on microstructure and mechanical properties (tensile strength, yield strength, elongation and hardness) of the C45 steel. Specimens undergoing different heat treatment lead to various mechanical properties which were determined using standard methods. Microstructural evolution was investigated by scanning electron microscopy (SEM). The results revealed that microstructure and hardenability of the C45 steel depends on cooling rate, austenitization temperature, holding time and heating rate.
Structure-Properties Relationships in Heat Treated Low Carbon Steel
The samples of AISI 1018 Low carbon steel were heated to austenite zone then cooled in different mediums with different cooling rates. Mechanical tests show increase in hardness, yield strength, tensile strength, modulus of elasticity, and yield/tensile ratio as cooling rate is increase. Ductility has inverse proportionality to cooling rate. The resulting microstructures show decreasing in grains sizes accompanying to cooling rate increase. The relations between mechanical properties and grains size are opposites of relations between mechanical properties with cooling rates. Hardness, yield strength, tensile strength, modulus of elasticity, and yield/tensile ratio increase as grains size decreases, while ductility decreases.
Surman Journal for Science and Technology , 2023
The main objective of this paper is experimental study of pack carburizing of carbon steels (AISI 1020) by using two parameters (holding time and carburizing temperature). This study was conducted by using electrical furnace. This process is carried out at temperatures of 950°C for durations time 90 minutes. From the experiment, the surface hardness and thickness of carbon layer was different according to the parameters used. The quenching medium that uses in this experiment is water, oil, sea water and air. For carburizing temperature at 950°C, the highest of surface hardness value for air is 128 HV that carburized for 90 minutes, the highest of surface hardness value for water is 224 HV that carburized for 90 minutes. For carburizing temperature of 950°C, the highest of surface hardness value for sea water is 166.9 HV that carburized for 90 minutes and for carburizing temperature at 950°C which is the highest of surface hardness value for oil is 126 HV. The thickness of carbon layer was between 40μm to 120μm. The result indicates the carburizing process accelerates the diffusion of carbon atoms into the surface, thus increasing the thickness of carburized layer as well as the surface hardness.