Selecting Optimal Ingot Sizes for Bethlehem Steel

Abstract

To take maximum advantage of a new ingot mold stripping facility, which was installed in 1984 at the Bethlehem Plant, we developed a two-phase, computer-based procedure for selecting optimal ingot dimensions and internal ingot mold dimensions. Phase 1 generated feasible ingot and internal ingot mold dimensions consistent with the new stripper's capability and with foundry, steelmaking, metallurgical, mill, and shipping yard constraints. Phase 2 then used a set-covering approach to select the optimal ingot and internal ingot mold sizes from among the feasible sizes. Based on model results and following trial mill tests, full production use of new mold sizes has affected the entire plant operation, resulting in over $8 million annual realized savings.

The simulation of the preparation of the ingot with liquid core

“…The ingot is octagonal and the speci c sizes are shown in Table 2 with 10017 nodes and 47017 grid elements. The height to diameter ratio and the preliminary ingot taper are 1.5 and 3.93%, respectively [16], which are proper according to the widely accepted censuses. The casting material is gray cast iron, which contains 3.3-3.9%C, 0.6-0.9%Mn, 1.8-2.3%Si, P < 0.15 and S < 0.12.…”

The Simulation of the Preparation of the Ingot With Liquid Core

“…The ingot is octagonal and the speci c sizes are shown in Table 2 with 10017 nodes and 47017 grid elements. The height to diameter ratio and the preliminary ingot taper are 1.5 and 3.93%, respectively [16],…”

A Binary Cat Swarm Optimization Algorithm for the Non-Unicost Set Covering Problem

“…The SCP has been applied to many real world problems such as crew scheduling [19][20][21], location of emergency facilities [22,23], production planning in industry [24][25][26], vehicle routing [27,28], ship scheduling [29,30], network attack or defense [31], assembly line balancing [32,33], traffic assignment in satellite communication systems [34,35], simplifying boolean expressions [36], the calculation of bounds in integer programs [37], information retrieval [38], political districting [39], stock cutting, crew scheduling problems in airlines [40], and other important real life situations. Because it has wide applicability, we deposit our interest in solving the SCP.…”