| In a new alternative to carburizing, an integrated control device manages dosing of liquid methanol (rather than endothermic gas) and optimizes the differential pressure to maintain the chemical composition for an effective and efficient heat treating process. |
Resourceful metalcasters have been adopting ancillary capabilities like prototyping, machining or fabricating to their operating portfolio, to enhance their appeal to customers and diversify their sources of revenue. To that list of “new” offerings add heat treating, increasing the number of operations that have been performing thermal processing all along.
Heat treating is frequently the final process stage for critical aerospace or automotive components, so the revenue opportunities for metalcasters are significant.
It’s also an area of emerging technology, so while there are opportunities for operations to make a breakthrough with new capabilities, there are challenges to mastering the technology with efficiency and proficiency.
One new development in heat treating is an alternative to hardening steel by nitrogen-methanol carburizing. It was developed by Brkert Fluid Control Systems (www.burkert.co.uk) and researched and tested the Institute for Materials Engineering (IWT) in Bremen, Germany.
Brkert’s Liquid Fluid Controller (LFC) is an intelligent, integrated, costeffective device for regulating several liquids, or a liquid and a gas, simultaneously. Until recently this sort of control was comparatively complex and required using individual components. This raised investment and maintenance costs and complicated the task of interfacing the controllers. Brkert’s LFC is a compact, integrated device that optimizes the differential pressure process for liquid flowrate measurements, to achieve precise, fast, and repeatable measurements.
The LFC measures flow rate accurately and speedily, so it is well suited for the dynamic control or metering of liquids like deionized or demineralized water, methanol, or low-viscosity oils.
In the new carburizing process, liquid methanol rather than endothermic gas is introduced directly to a furnace and the solution is regulated using the Brkert LFC. The advantages are that the dosing of methanol is precise and transparent, with the dosage levels, consumption, and flow values measured and documented so they can be reproduced with reliability.
Methanol is cheaper than endothermic gas and easy to store, and it can be fed into the furnace in exact measurements, according to the process requirement. In addition, there are no investment or operating costs for an endothermic gas generator. Brkert maintains its method is more energy efficient, too.
In the ITW test at Bremen, the Brkert LFC automatically controls methanol dosing, reacting to disturbance variables like pressure (such as fluctuations in pump pressure upstream of the LFC, or in the pipe downstream of the LFC) and dynamically adjusts the methanol dosage to maintain a constant mixture. The high-precision measuring capability and adjustment keeps operating costs low and guarantees optimal efficiency, according to the developer.
In contrast to flow controllers that measure according to the Coriolis principle, the LFC uses differential pressure measurement. This means substantially lower initial costs, and because the measurement principle of the LFC requires no moving parts (e.g., impellers) the maintenance and replacement costs also are reduced.
ITW researchers note the particular advantage of improved process data available thanks to recording methanol consumption and temporal flow characteristics. “The complete process can be fully documented,” according to Dr.-Ing. Heinrich Klmper-Westkamp. “Within one test series, we can analyze the impact of various process data on the treatment of a component and develop improved reproducible processes.”