The research objective is to determine the total size of the lot of iron scrap orders, and the total cost of the company's inventory before and after carrying out the method of controlling iron scrap inventory using the Wagner Within Algorithm method. Demand forecasting uses the Single Moving Averge, Weight Moving Average, and Exponential Smoothing methods. Based on the results of the study, the total lot size of iron scrap material orders is smaller than the size of previous lot orders without using the inventory control method, which is 15,362 tons per year. Total inventory of Rp. 105,076,125,840 and the total cost is more optimal when compared with the total cost of inventory with the company system that is Rp. 109,734,165,840 so that the company can save costs by Rp. 4,658,040,000.

The research objective was to determine the application of Supply Chain Management (SCM) at PT Brataco Chemical Medan Branch. This research used a descriptive approach with SCM analysis. Based on the research results, the company's suppliers consist of suppliers of main and supporting raw materials. Purchases of raw materials are made by pre-order with a credit payment system. Incoming raw materials will be checked with order data. If the item does not match the order, it will be returned to the supplier for replacement. Meanwhile, the appropriate goods will be placed in the warehouse and then the production process is carried out. The production process is carried out in two stages, namely the first stage to produce low TDS & nearly neutral PH and the second stage to produce Aqua Demineralization. The production results are then checked for conformity with the predetermined standards. Products that pass will be distributed to consumers using a car provided by the company. Orders that do not fit or are defective, then consumers can return to the company to be replaced with new goods.