Breakthrough in heat treatment process

The MLC 9000 PID Multi Loop Controller system has brought integrated control to the nitriding heat treatment process at Wallwork Heat Treatment.

The MLC 9000 PID Multi Loop Controller system has brought integrated control to the nitriding heat treatment process at Wallwork Heat Treatment.

The system, from West Instruments, was designed and engineered by West’s distributor, The Industrial Pyrometer Company (IPCO) of Birmingham. The application provides Wallwork operators with greater precision and flexibility in controlling the critical breakdown of ammonia gas inside the nitriding furnace, to produce nitrogen for diffusion into the surfaces of metal components. The advanced communications capability and modular loop design of the West MLC9000 system has enabled control of the process to be fully integrated, thus eliminating many of the problems associated with the use of integrated stand-alone furnace control devices.

Where before there was no overall visibility of the process, the latest touch-screen technology provides operators with a single window through which they can monitor all control parameters, make changes where necessary and retrieve data for analysis. A combination of PID integrity and bus integration capability overcomes previous difficulties of access to PID control by the furnace PLC and fast centralised programming replaces the time-consuming configuration of individual standalone controllers.

Wallwork HT, a heat treatment specialist, is using the West MLC 9000 system in a nitriding furnace to control temperature, pressure and flow rate parameters, critical for achieving optimum ammonia dissociation. Nitrogen produced from this dissociation is diffused into the surfaces of metal components to improve their strength and resistance to wear. The process calls for tight control of the ammonia flow rate relative to the temperature and pressure in the nitriding retort to ensure a controlled depth of hard alloy nitrides of correct composition is produced.