Between May and December 2023, Nutec Bickley will manufacture and install five completely new furnaces, along with fully modernized combustion system, for a leading US manufacturer of high-quality alloy steel and carbon steel closed-die forgings. Onsite work will be completed by Nutec Bickley’s expert team one furnace at a time, so that in any given month no more than one furnace will be out of operation, in order to help the customer keep its production schedules fully on track.
This highly prestigious contract involves five new lift-up furnaces – two for tempering and three for austenitizing. Each furnace will be fitted with a comprehensively modernized combustion system (including replacement fans), latest control systems, complete fiber flues, and new exhaust and pressure control system, plus freshly insulated casings.
Operation based on a fuel-only control system
Each of these state-of-the-art combustion packages will be fully compliant with NFPA 86 standards, and the installations will comprise the complete supply of materials and instrumentation required to operate the furnace combustion systems, plus new sets of air and gas piping.
Operation will be based on a fuel-only control system (fixed air modulating gas) to allow maximum temperature uniformity potential for all cycles. The retrofitted furnaces will benefit from the incorporation of high-velocity nozzle mixing burners fitted with high-temperature burner blocks. These burners fire with a constant air volume while the control system regulates the gas input by modulating an impulse-bleed valve.
Meanwhile, the combustion systems will be equipped with an automatic air control valve on the main air manifold that will provide the means to adjust the maximum air volume the system can use, and to lower the air supply to the burners to ensure proper burner ignition conditions.
Close Monitoring and Control
All controls and instrumentation are mounted in a NEMA 12 rated console, ergonomically arranged for simple and logical operation. Appropriate alarms will be supplied for burner flame failure, loss of air, loss of fuel, and over temperature. The control panel will be installed next to the existing furnace panels and will be prewired and positioned before the furnace replacements begin. They will be wired across the quench pit to the local furnace areas prior to the first furnace being converted. This system will be designed in accordance with the NFPA 70 standard.
In order to achieve a completely coordinated command structure, a master PLC will be supplied to integrate the five furnaces and communication with the two existing quench tanks, manipulator/charging machine, the two panel views, the SCADA system, two recording units, and the central hydraulic system. The master PLC will be mounted in a separate NEMA 12 rated cabinet.
When complete, the newly lined units (9in/23cm thick ceramic fiber modules) will work to operational temperature ranges of 900°F–1950°F (480°C–1065°C) for the austenitizing furnaces, and 840°F–1600°F (450°C–1065°C) for the tempering furnaces. Installed thermal capacities will be 8 million Btu/h (2345kW) for the austenitizing furnaces, and 5.5 million Btu/h (1612kW) for the tempering furnaces.
As with all projects of this type, especially given the exacting timescales involved, carefully planned teamwork between customer and supplier will be a key factor in successful delivery and highest quality outcomes.
Rodrigo González, VP Metals at Nutec Bickley, commented: “We have long recognized the value of this approach, and we are committed to constant communication and status updates with our customers. In turn, they reciprocate with the same level of engagement in the process, resulting in a dynamic and mutually beneficial project result. We are always determined to make this work, and our observation over many years in this sort of undertaking is that the closer the cooperation and the better the flow of information, then the nearer one can get to the optimum progress levels.”