Analyzing of Cold Box Binder System and Determination of Its Eff ects on Cast Parts

Cores are used in casting process to form cavities, hole protrusions, recesses and casting products which are not possible to be shaped by the mold. In order to give strength and stiffness to the core, core sands and binders are used. There are several cold box systems in which different binders and gas catalyzers are used. For efficient productions such as automotive industry, pipe production, cooling systems cold box process are used because they can produce complicated tools, they have stable moisture content, they do not need any preheating, they have high strength and high precision. Because of his productivity, cold box process is used in most of the casting industry. For our research, of all cold box processes, we are going to use and analyze phenolic urethane cold box (PUCB) process. As we can understand from the name of this process, phenolic urethane cold box process is obtained by the reaction of two component with polyurethane. The constituent of Part I is a phenol-formaldehyde resin and the constituent of Part 2 is isocyanate. A polyaddition of the part 1 component, the phenolformaldehyde resin, and the part 2 component, the isocyanate, is initiated through basic catalysis, usually by means of gassing with a tertiary amine. The hardening reaction is very fast, which makes the PU cold box process attractive for the highly productive production of series components in particular. Different ratio (50/50, 40/60, 60/40) of Part 1 and Part 2 with DMEA (dimethylamine) gas cold box system is compared. They were tested with 3-point bending and analyzed effect on casting conditions. Introduction Phenolic resins have many various applications. Especially for heavy duty conditions, bonding of particle and fiber structure, those resins are used commonly. The casting industry is also one of the application area. In foundry process, resins are used in core making and mold making process. Different properties are expected from resins for these two sections. For example, the immediate and long-term strength is very crucial for core making process [1]. Hot box and cold box systems are common process for core making. Thin wall and detailed cores are made with hot box, relatively thicker cores are made with cold box process [2,3]. Cold box system is consisted of three parts. One of them is a resin that is generally a phenolic urethane resin, the other part is a crosslinking agent. The last part is an activator that is generally an amine (Fig 1)[4]. Figure 1 Cold box curing system[4] There are few researches about cold box systems. Some of them are given below. In study of Liu F. and his friends in the year of 2017, were investigated the factors which affect performance of no-bake resin bonded sand (NBRBS) including furan resin, curing agent and boric acid content and kinds of collapsibility agents and base sand. In the results are shown that the optimization of the comprehensive performance of NBRBS is achieved when the furan resin addition is 1.6 wt% of base sand content and the curing agent addition is 50 wt% of furan resin content. [5] In a work conducted by Stauder B. and his friends, were investigated the foundry sand core properties which are a key requirement for high precision casting process development. In this work is demonstrated the potential to evaluate mechanical and functional sand core UCTEA Chamber of Metallurgical & Materials Engineers’s Training Center Proceedings Book 1092 IMMC 2018 | 19th International Metallurgy & Materials Congress properties using precisely acquired 3-point bending test load curve data applying standard bending test geometries. The organic binder systems which have been investigated were: coldbox, hotbox and warmbox. [6] In a work conducted by Gonzalez R. and his friends in 2011, is presented the results of tests carried out on mixtures of sand and binders used in phenolic urethane cold box cores. In this work were analyzed: two binders and silica sand with two grain size distributions. The cores were blown with blends of sand that had resins within the range of 0.8 to 1.15%. Some tests were carried out for obtaining the viscosity, polydispersity, molecular weight and refractive index of the resins. The aim of this study was to determine which resin fulfills the critical conditions to obtain sound aluminum castings. [7] In our present work, we will keep stable the amount of sand and the Part 2 while in Part 1 we use a phenolic Afterwards, we use another resin which belongs to an A industry. Resin characterization tests were done., 3-point bending test. After, different ratios of Part 1 and Part 2 mix were compared and with standard core samples. All samples were tested on casting trial with cast iron. A cube model was determinate for casting trial.