ALD’s newly developed “Velocity Gauge” enables the gas flow in the batch chamber to be checked during gas quenching. It allows preventive testing of the quenching system, supports fault analysis in the event of quenching problems and helps to ensure the quality of gas quenched components.

An important process parameter in gas quenching is the flow velocity of the circulated quenching gas. In addition to other parameters such as quenching pressure, gas type and -temperature, it determines the quenching intensity. This in turn has a decisive influence on the achievable component properties such as hardness, microstructure and distortion. It is therefore important to ensure that these process parameters are measured and documented. While gas temperature and gas pressure are recorded and documented by appropriate sensors, the gas velocity and its uniformity in the effective space of the quenching chamber is generally not recorded. If changes in the flow velocity profile occur after a longer period of operation, this is often only detected when the component quality deteriorates. We therefore recommend having the flow velocity and distribution checked at regular intervals during quenching. For this measurement, a so-called “Velocity Gauge” is used, which works according to the physical measuring principle of a Prandtl-sensor.  This makes it possible to measure the distribution of the flow velocity over the base area of a quenching chamber without great effort. The selected measuring principle and the simple measuring setup ensure that the measurements are reproducible and independent of operating influences.

Insertion of a Velocity Gauge into the quenching chamber of a SyncroTherm

Following the measurement, a protocol with the current measurement data is generated. This data can be compared with the data at the time of delivery of the quenching system. In case of deviations, the analysis of the measured flow profile enables conclusions to be drawn about possible causes of faults in the system.

ALD offers the measurement of the gas flow in quenching chambers as a service. It makes sense to do this preventively, e.g. as part of the annual system maintenance. However, the measurement can also be carried out at any time and at short notice if the component quality has changed and if it is to be ruled out that changes in the gas flow distribution are responsible.

The time required for a measurement at the plant is approx. 2 hours including all necessary preparations. The measurement is documented with a test certificate and a corresponding inspection plate is attached to the system.

If you want to ensure that your gas quenching system will continue to meet your quality requirements with regard to gas flow and distribution in the future, please do not hesitate to contact our service.

ALD Vacuum Technologies GmbH
Hall 4.1 Booth C-059