Low Pressure Carburizing

Low pressure carburizing provides many advantages over traditional atmospheric carburizing: absence of oxidation, precise control of the process and case-depth.

ECM Technologies Infracarb® process
Infracarb® is the patented process used in ECM Technologies's ICBP® vacuum carburizing systems or low pressure carburizing systems. More precisely, Infracarb® consists of an alternate injection of hydrocarbon (for carburizing) and a neutral gas (for diffusion). It relies on the thermal cracking of hydrocarbon at low pressure (7-13 mbar).

The ECM Technologies Infracarb® process ensures that all the process parameters are controlled for optimal results.

Propane C3H8 or Acetylen C2H2 for carburizing, and, nitrogen N2 for diffusion are the most commonly used gases in Infracarb® in standard conditions. Number and duration of the steps depends on the case-depth required. Fine tuning these parameters allows precise control of low pressure carburizing process results on ECM Technologies's ICBP® installations.
Simulations of Infracarb® allow fine tuning of recipe parameters to reach the center a perfect control of case-depth.

ECM Technologies CBPWin is the Infracarb® process-simulation software a tool used to assist the metallurgist in the development of proper cycle recipes. It offers a great deal of flexibility, allowing input of key process parameters, targeted effective case depth and maximum/minimum carbon contents at the end of each boost and each diffusion step, and outputs the cycle recipe.

On the other hand, the system works equally well by putting in results and “working backwards” to determine the process parameters necessary to achieve a specific result. This is particularly useful, for example, when trying to avoid carbide formation in the tips of gear teeth, or carbide networking in high sensitive materials.

In ECM Technologes's ICBP® systems, enrichment is brought to saturation as long as enough carburizing gas is supplied and parts are adequately positioned to enable gas flow to reach centre of the load.

If you are to treat parts with complex geometry or particularly dense loads, acetylene C2H2 is the answer, currently used on 40% of ECM Technologies's installations in service. With higher enrichment capabilities than propane, acetylene responds to higher requirements for carburizing homogeneity and is suited for complex-shaped parts, with greater surface to treat (bores, blind holes). Acetylene tests run by ECM Technologies on diesel injectors showed a 41% higher carbon enrichment than with propane at the base of the part.

ECM Technologies has developed and patented its acetylene process. Consistent with Infracarb®, it uses alternate injections of acetylene and nitrogen. Beyond advanced uniformity, acetylene (combined with the diffusion capabilities of nitrogen) preserves a very uniform result in case of "soft spots" or washing inconsistencies, as tests have demonstrated.