This is a model of the soaking pit furnace. It is described in different sources [1, 2]. [1] A. Alan B. Pritsker, Simulation with Visual SLAM and AweSim, 2nd ed. [2] Труб И.И., Объектно-ориентированное моделирование на C++: Учебный курс. - СПб.: Питер, 2006 Steel ingots arrive at a soaking pit furnace in a steel plant with an interarrival time that is exponentially distributed with mean of 2.25 hours. The soaking pit furnace heats an ingot so that it can be economically rolled in the next stage of the process. The temperature change of an ingot in the soaking pit furnace is described by the following differential equation. d(h_i)/dt = (H - h_i) * C_i, where h_i is the temperature of the i-th ingot in the soaking pit; C_i is the heating time coefficient of an ingot and is equal to X + 0.1 where X is normally distributed with mean of 0.05 and standard deviation of 0.01; and H is the furnace temperature which is heated toward 2600 F with a heating rate constant if 0.2, that is, dH/dt = (2600 - H) * 0.2. The ingots interact with one another in that adding a "cold" ingot to the furnace reduces the temperature of the furnace and thus changes the heating time for all ingots in the furnace. The temperature reduction is equal to the difference between furnace and ingot temperatures, divided by the number of ingots in the furnace. There are 10 soaking pits in the furnace. When a new ingot arrives and the furnace is full, it is stored in an ingot storage bank. It is assumed that the initial temperature of an arriving ingot is uniformly distributed in the interval from 400 to 500 F. All ingots put in the ingot storage bank are assumed to have a temperature of 400 F upon insertion into the soaking pit. The operating policy of the company is to continue heating the ingots in the furnace until one or more ingots reach 2200 F. At such a time all ingots with a temperature greater than 2000 F are removed. The initial conditions are that there are six ingots in the furnace with initial temperatures of 550, 600, 650, 700, 750 and 800 F. Initially, the temperature of the furnace is 1650 F, and the next ingot is due to arrive at time 0. The objective is to simulate the above system for 500 hours to obtain estimates of the following quantities: 1) heating time of the ingots; 2) final temperature distribution of the ingots; 3) waiting time of the ingots in the ingot storage bank; and 4) utilization of the soaking pit furnace.