Scanning Induction Tempering

When you need a scanning scheme

A short neck can be stiffened locally in a stationary area. For a long track with transitions, a scanning scheme is preferable: it coordinates the speed of the inductor, the rotation of the part, the inclusion of the shower and the exit beyond the boundaries of the working zone.

The standard description of such an installation is PLC, touch panel, rotation of the part and vertical or longitudinal movement of the inductor. Automatic loading, pyrometry, additional axles and extended mechanics cannot be promised as a basic equipment without a separate technical specification. UralInduktor develops the concept and technical solution, and the Chinese factory performs detailed design and manufacture of the machine.

What data is needed for machine design

For scanning hardening, it is important to describe not only the detail, but also the trajectory of the process. The same diameter shafts may require a different stroke of the inductor due to the length of the zone, grooves, burts and areas that need to be missed without heating.

part material, its initial heat treatment and the required hardness after quenching;

the maximum length of the part, the length of the hardened zone, diameters by sections and transition elements;

the required effective depth of the layer and the allowable spread over the length;

what areas should remain unheated and what kind of entry or exit is needed;

allowable beating, folding and requirements for subsequent machining;

tempering cooling environment, restrictions on the flow and quality of water or solution;

performance, loading type, batch sizes and number of sizes.

How a scanning machine differs from a manual or conventional installation

Manual LN is useful for repair and hard-to-reach area when the operator fails the remote inductor. The stationary installation is suitable for short circular zones. For stable programmable movement along a long surface, a machine is needed, where the electrical part and mechanics work as a single system.

That is why the fixed electrical characteristics of the generator are not published for scanning machines. Solutions based on AVZ or AVN can be designed for the task, and in some small narrow zones - AVV or AVVS. The final choice depends on the diameter, the required depth of the layer, the length of the core, the speed of passage and cooling. The LN series is considered as an auxiliary option for individual manual operations, but not as the equivalent of a scanning complex.

What decides the metallurgy process

In scanning quenching, the connection between the time of stay of the zone under the inductor and the rate of heat transfer to the metal is especially important. Too high speed will give underheating and insufficient depth of the layer; too low can lead to overheating of the surface and increased deformation. The result is also affected by steel hardiness, real clearance, rotation of the part, shower shape and cooling delay relative to heating.

The depth of the layer and the hardness are confirmed by testing, and not by calculating the current penetration. The shower position, flow rate and composition of the solution are adjusted according to the test part, since the geometry of the transition and the concentration of the polymer change the tempering pattern.

Correct approximate calculation of working speed

The following approximate example supports an initial selection of the power and speed range. Assume a 50 mm diameter shaft must be scan-hardened over a length of 500 mm, with a surface layer approximately 3 mm thick to be austenitised. The heated annular layer volume over this length is π × 500 × (25² − 22²) mm³, approximately 222 cm³. The layer mass is approximately 1,74 kg.

If you take the mean heat capacity of the steels 0,60 kJ/(kg·C) and heat from 20 to 850 °C, the useful heat will be 1,74 × 0,60 × 830 ~ ≈ 867 kJ or about 0,24 kWh. With a imputed total CDI of the 50 process, a percentage of the network would require approximately 0,48 kWh. If the average electric power during the process of about 40 kW, the calculated time will be about 43 seconds and the approximate speed of the passage is about 11 - 12 mm/s. In fact, heat goes deeper than the calculated layer and beyond the zone, so it's just the starting range: speed is specified by material, rotation, transitions, and operation of the solid soul.

How is the acceptance and what is included in the delivery

A simple inductor is usually included if it is provided in an agreed base configuration. Complex profiled inducers, sets of interchangeable inducers and special devices are calculated separately. After assembly, the plant checks the equipment with the inductor ordered. Then, in Miass, a second check is carried out with full connection without load.

Management and documentation - in Russian. commissioning is performed by the customer on his details with the execution of acts. Warranty 18 months under the contract, with reference to shipment or commission act. Price on request. The depth of the layer, performance and deformation are confirmed by testing.

What to send for selection

Send the detail drawing, length and location of the hardened area, steel grade, required layer depth and performance. We will propose the concept of a scanning complex, select the series of ABC, ABB, AVZ, AVN or LN in an acceptable role and agree on a test program. Price on request.