سباكة الصلب عالي السبائكية AISI321 باستخدام السباكة الرملية

Abstract

In this work, sand casting was used to obtain high-strength steel AISI-321 by melting alloy AISI304 using sand casting. This is in addition to titanium using an induction furnace, which is considered one of the metal forming processes that originated from the principle of casting in sand molds. In general, Ti will oxidize quickly in the melt if it is exposed to air in typical sand/investment casting processes; Titanium element provides greater resistance to inter granular corrosion. Stainless steel alloy 321, which differs from 304 in that it contains a percentage of titanium, which has given it the property of being used at high temperatures, which has increased the need or demand for stainless steel casting in some industries and due to the difficulty and complexity of producing some pieces or parts using SS304 (wrought) forging alloy by Machines, so that it became necessary to search for a way to improve quality and reduce time and cost, using plumbing technology, although information about this technology is not available in open references. The ability to cast stainless steel is affected by a variety of factors, such as the time and degree of melting, the types of additives, and the time of total solidification. In addition, there are some other casting factors that have a direct impact on the quality of casting stainless steel, such as the sand mold materials, their type, preparation of the sand mold, and the heat treatment steps. This research includes two parts, a theoretical part that includes the steps of sand casting, and the second part related to the practical side, where the effect of some casting factors was studied, which includes the weight and quantity of addition of titanium (300 to 1000 grams), the time of addition and pouring from (3 to 15 minutes), as well as a study of heat treatment and its effect. This is due to the quality of the stainless steel alloy under study. In each experiment, 100 kilograms were used on stainless steel 321 and 304. The practical experiments were completed in several experimental stages, and in each stage, some modifications were made so that they were based on previous results. The results of the chemical analysis of the last five samples showed a gradual increase in the amount of Ti% until it reached about 0.4%. The tensile strength and yield strength were at acceptable values compared to the Wrought SS321 and cast SS (CF) alloys, an austenitic stainless steel, where the lowest value was (200 and 198) MPa and the highest value was (559 and 315) MPa, respectively. The hardness values were between (145 to 149). Key words: sandcasting, Austenitic SS321, SS304, FeTi.