Computers not only make for better machine tools, they also make the materials processed on those machine tools better. Ispat Inland Bar Products (East Chicago, Indiana), a division of Ispat Inland Inc., has introduced a new series of steels called EM or Enhanced Machinability steels. The EM steels are not new formulations. They were developed by optimizing the chemistries of such standard steel grades as 1018, 1117, 1137, 1141 and 1144.
Ispat Inland is committed to making more and better free-machining steels than have been possible in the past. The basic oxygen furnace/caster at the East Chicago complex is one of the tools it is using to achieve that goal. The BOF shop has new computerized operating controls and slag-free tapping. The ladle metallurgy station features arc reheating for accurate temperature control, electromagnetic stirring for improved homogeneity, computer-controlled alloy additions and reagent injection, and a host of other state-of-the-art features. These, along with controlled solidification rates and below-the-mold electromagnetic stirring, work to ensure good soundness and diffuse center segregation patterns, ensuring the consistent quality of the firm's free-machining steels.
The refined control of the production process results in EM steels that are more consistent from batch to batch. For the user, the uniformity of the steel not only reduces time-consuming adjustments that are sometimes necessary with new batches of steel, but also reduces unforeseen material-related crashes.
According to the steelmaker, users of EM steels can expect generally longer tool life because of the bar stock's improved consistency. Alternately, users may be able to reduce machine cycle times while maintaining current tool life. The more uniform performance in such aspects as chip control and size repeatability also contribute to the cost-effectiveness of these steels.
Because of the greater consistency of the EM steels, there is less need for the operator to monitor the machine's operation, and he or she has more time to attend to other responsibilities, such as running another machine or inspecting parts. The consistency of the steel effectively eliminates a variable from the operation, allowing the user to concentrate on other aspects of the operation to optimize the process.