Multi-furnace heat treat project for major steel forger

Between May and December 2023, NUTEC Bickley will manufacture and install five completely new furnaces and a 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 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 have a comprehensively modernized combustion system (including replacement fans), the latest control systems, complete fiber flues, a new exhaust and pressure control system, and freshly insulated casings.

Each state-of-the-art combustion package will be fully compliant with NFPA 86 standards. The installations will comprise the complete supply of materials and instrumentation required to operate the furnace combustion systems, plus new air and gas piping sets.

The operation will be based on a fuel-only control system (fixed air modulating gas) to allow maximum temperature uniformity potential for all cycles. The furnaces will benefit from incorporating high-velocity nozzle mixing burners fitted with high-temperature 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 central air manifold that will provide the means to adjust the maximum air volume the system can use and to lower the burners' air supply to ensure proper burner ignition conditions.

Fig. 1 NUTEC Bickley lift-up furnace for forging

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 overtemperature. The control panel will be installed next to the existing furnace panels, prewired, and positioned before the replacements begin. They will be wired across the quench pit to the local furnace areas before the first furnace is converted. This system will be designed following the NFPA 70 standard.

To achieve a wholly coordinated command structure, a master PLC will be supplied to integrate the five furnaces and communication with the two existing quench tanks, the 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–870°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 critical factor in the successful delivery and highest quality outcomes.

Rodrigo González, VP of 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. Our observation over many years in this sort of undertaking is that the closer the cooperation and the better the flow of information, the nearer one can get to the optimum progress levels."