ECM Furnace Benefits

Integrated and Ecological

ECM Technologie's™ vacuum furnaces are an economic and ecological alternative. With ICBP® furnaces, gas quenching takes place in a specific cell in which the loaded parts are quickly transferred from their heating cell after low pressure carburizing.

The parts are then cooled by a high pressure gas injection, up to 20 bar, stirred by two turbines. Unlike with oil quenching, it is no longer necessary to wash, recycle or treat the effluent when upon exit. Gas quenching is a cleaner and cheaper process which respects the environment. It is a uniform, predictable and reproducible process because it eliminates the calefaction phenomena generated by oil quenching.

Gas quenching produces significant quality gains which can easily lead to savings, such as a decreasing percentage of waste or a reduction in post machining operations. With gas quenching, parts are closer to their final dimensions, with a high level of reproducibility. Companies like Delphi, which now use oil and gas quenching, increase the proportion of gas quenched parts for diesel pumps parts while keeping the oil quenching for more massive components.

Metallurgical Results

With ECM's Low Pressure Carburizing solutions, oxidation is eliminated, thermal treatment being carried out in a vacuum or partial pressure of gas-free oxygen. Carburized layer interface with the base material is a lot more regular. Carbon profile never shows decarburization on the surface: no bell-shaped profile!

The carburizing depth can also be precisely controlled; results have shown a very high degree of uniformity in batches of parts and even on one part only. Moreover, the difference in enrichment depth between the side and the bottom tooth is greater than 30% after conventional carburizing and oil quenching. After low pressure carburizing and gas quenching it is less than 15%. This reduces the specification carburizing depth and thus the cycle time. It also helps reduce stress and toothing distortion after quenching.

Mechanical Properties

There is an excellent hold to the pitting resulting from the absence of intergranular oxidation (IGO).

The ECM process makes a difference when strain or shock resistance is of importance, e.g. to increase torque in new generation gearboxes.

With perfect control of the carbon and nitrogen (if carbonitriding) enrichment, low pressure carburizing contributes to increase the surface compressive stresses which favor strain resistance. On our systems, low-pressure carbonitriding® and well controlled gas quenching lead to improved mechanical properties (shock and strain)

Controlling Distortion

The heat treatment does not necessarily imply that the parts will not meet the dimensional tolerances. ECM's processes, especially gas quenching, allow a better distortion control of the parts because the cooling rate after carburizing can be easily adjusted for each part shape according to specific procedures. The momentary interruption of the quenching- STEP QUENCH - is an additional tool which reduces heat stress in the material during quenching and improves distortion.

The results are very uniform, between parts and loads. Distortion is generally predictable, and its amplitude and direction more homogeneous. Therefore in some situations, they can be anticipated during processing before treatment.

• At best, the expensive final treatment is unnecessary.
• In general, the amount of material to be removed and the number of treatments are reduced.

Environmental Benefits

• No open flames or curtains needed
• No added heat from furnace in heat treat
• Cleaner facility
• Safe operation (no hot doors or hot moving parts)
• Reduction of process gas use
• Reduction of emissions

When using gas quenching system: No environmental issues with oil present in facility; No post-heat treat wash necessary