Material Handling, Packaging & Transportation
This paper introduces a special failure case of a main hoist reducer on ladle cranes. A maintenance team noticed abnormal signs in the bearings. During the maintenance, it was found that the keys in the main hoist gear reducer were either displaced or missing and staggers occurred between keyseats and keyways. After repair, the causes of displaced or missing keys were discussed and verified. Finite element modeling was utilized to analyze the interference of gears and shafts to explain why keyseats and keyways staggered, which showed an inappropriate fit of the design in general. Suggestions for improvement and repair are provided.
For economical operations of steel works, it is important to efficiently plan routes of torpedo cars. Today’s stationary detection methods (e.g., radio frequency identification) have the disadvantage that torpedo cars are detected only at this stationary location and there is no live movement tracking of the torpedo cars. Furthermore, for all-in-all tracking, the entire track network must be equipped with stationary sensors. SMS group has chosen a new approach to equip the individual torpedo cars with battery-powered differential global positioning system modules. First test measurements showed location accuracies below 2.5 m circular error probable and the modules are able to transmit the live location information via radio transceivers over distances of up to kilometers to a common base station. There the data is evaluated and made available to connected software modules.
This paper evaluates several active and passive arc flash reduction solutions based on NFPA 70E. A case study simulation is performed on an existing conventionally coordinated low-voltage switchgear system based on IEEE 1584-2018 standard, and the comparative results are presented. For each solution, the concept, the achievable energy levels and the associated cost of implementation are provided. A discussion of trade-offs and benefits of various solution is presented to help electrical safety supervisors make a sound judgment according to their requirements.
Blast furnace hearth refractory systems are exposed to high temperatures and harsh conditions during operation, causing refractory degradation that often limits the furnace campaign life. Thermocouples are used to monitor the hearth wear. Proper interpretation of measurements is critical to understand the reason for the wear and determine the hearth conditions. This paper presents what-if scenarios, using 2D finite element analysis to evaluate the effect of cooling water temperature, iron fingers, air gaps between refractory and shell, and refractory/skull profile on the thermocouple temperatures. The findings are used to provide operational and maintenance recommendations to improve hearth refractory life.
A new reversing cold mill for stainless steel sheet and foil was successfully started up in China in early 2018. It is a 20-high Sendzimir mill that has first intermediate roll shifting and double “As-U-Roll” (AS-U) mechanisms as a means of controlling flatness. One of the key technologies is to eliminate thickness change caused by AS-U movement. Another is to control flatness accurately especially at quarter and edge part, which tends to become wavy easily. The advanced control system has overcome these and achieved high quality in both thickness and flatness. The features of the control system and application results are shown in this paper.
JFE Fukuyama No. 2 CGL (continuous galvanizing line) produces galvanized steel sheets for automobiles, structure materials and home appliances. It is required to decrease environmental load material. Coating equipment was introduced to produce chromate-free galvanized steel sheets. The following three points were decided at the time of introduction: Designing a CGL that can produce chromate-free steel sheets for structure materials and automotive exposed panels; dividing construction into three phases to reduce the impact on the existing level of production; and introducing a vertical roll coater for a chromate-free film coating with uniform thickness. The new and improved No. 2 CGL started up on May 2018 and began commercial production.