May/June_AMP_Digital

FEATURE A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A Y / J U N E 2 0 2 0 6 2 deflector is used (Fig. 2). The tapered top plate deflects the gas away from the barrier. The unique design means the plate is supported on either four or six support legs. As it is not in contact with the barrier, no force is applied directly to the barrier and the force is shared between the support legs. Performing a temperature uniformity survey (TUS) to comply with AMS2750E/CQI-9 standards requires that the survey, analysis of data, and reporting, is performed in agree- ment with strict criteria. This can be tedious and lengthy un- less using a customized TUS software analysis package such as the PhoenixTM Thermal View Survey software. Applying the thru-process monitoring technique there is no hardwired link between the monitoring system within the furnace and the outside world. To achieve real timemea- surement, as if using trailing thermocouples, the data mea- surements need to be transferred remotely. This is achieved using a high-performance two-way radio telemetry system. The temperature readings are transmitted as a RF signal from the data logger via external barrier antenna from inside the furnace to a receiver connected to the external monitor- ing PC. The two-way communication protocol allows not only live data collection for profiling or TUS work but also direct control of the data logger (reset/download) inside the furnace (Fig. 3). CASE 2: SEALED GAS CARBURIZING WITH INTEGRAL OIL QUENCH A common process in today’s heat treatment indus- try is the carburizing of lower cost steel products for use in the automotive industry. To achieve this process a popular heat treatment technology used is a sealed gas carburizing 6 furnace with an integral oil quench. For such furnace tech- nology the historic limitation of thru-process temperature profiling has been the need to bypass the oil quench and wash stations. Obviously passing a conventional hot barrier through an oil quench creates potential risk of both system damage from oil ingress, barrier distortion, and general pro- cess safety. In such carburizing processes the oil quench rate is crit- ical to both the metallurgical composition of the metal and elimination of product distortion and quench cracks, so the need for a monitoring solution has been significant. Reg- Fig.2 — Thermal barrier fitted with quench deflector designed specifically for surveying LPC batch furnaces with high pressure gas quenches. Fig. 3 — Thru-process temperature monitoring system loaded into a batch furnace with TUS frame to complete a temperature uniformity survey. Fig. 4 — Thru-process temperature monitoring system for use in sealed carburizing furnace with integral oil quench. To the left is the inner sealed thermal barrier and data logger and on the right is the outer structural frame containing sacrificial insulation.