In order to reduce fuel consumption and CO2 emissions, to respect actual environment norms, vehicle weight need to be reduced. Moreover, safety norms impose continuous crash resistance improvement for this reason Advanced High Strengh Steels, which present excellent mechanical properties, are consequently increasingly used in industry, both in sheets and fasteners.
If on one hand the steels used for Fasteners application offer great mechanical performances, on the other hand they are susceptible to corrosion phenomena and that is the reason why the components have to be coated.
The electrochemical deposition is the only process able to apply a very thin coating also in threaded components with complex shapes which vary in thickness. A disadvantage of the electrochemical deposition is the hydrogen formation and adsorption in the metal substrate during the process. When the strength of steel is higher than 1000 MPa, the fastener could be highly sensitive to hydrogen induced delayed fracture. This phenomenon in threaded components can be caused by hydrogen absorbed during pickling and electroplating processes or during corrosion reactions.
Delayed fracture is difficult to be detected and usually happens suddenly for these reasons it becomes fundamental the materials selection and the hydrogen content monitoring in the finished fasteners.


HELIOS 2 GALVANIC is an innovative laboratory instrument that can be used to evaluate the hydrogen adsorption during the galvanic processes.

HELIOS 2 GALVANIC can also be used as a laboratory equipment to compare the hydrogen activity of different galvanic baths. The test method is based on the elaboration of the permeation curve obtained for ARMCO Pure Iron sheets using the process conditions applied in galvanic industry (current density, test solution, temperature, liquid circulation, air insufflation, etc.).

Moreover the Instrument can be also used to optimize inhibitors concentration, pickling temperature, help galvanic bath formulators…

Once acquired the signal that depends on the hydrogen flux through the examined test sample, is processed by proper mathematical codes (by means of a dedicated panel PC) and hydrogen bath activity is evaluated.

HELIOS 2 GALV is a completely automated instrument!

Letomec offers customized instruments and consultancy to define optimal hydrogen charging conditions (current density, electrochemical solution, re-circulation of the test solution, air circulation, etc.).

The HELIOS Platform including HELIOS 2 GALVANIC is coverd by the Patent N. EP 2912452 B1.


HELIOS 3-FASTENERS is an innovative solution to get fast, precise and repeatable measurement of diffusible hydrogen content in metallic samples.

HELIOS 3-FASTENERS can be used:

  • to measure diffusible hydrogen content in electroplating components (bolts, fasteners, springs, etc.) foundries, castings, metal manufacturing, welding and fabrication process samples;
  • as laboratory instrument for R&D applications.

Once acquired, the signal is processed by proper mathematical codes (by means of a dedicated panel PC), in order to return the diffusible hydrogen content.

HELIOS 3 FASTENERS can be used to estimate the level of diffusible hydrogen that can cause a reduction in mechanical properties of a metallic component. The estimated value can be used to evaluate the suitability of supplied batches of fasteners or to optimize processes such as dehydrogenation duration. It can also be used to assess the effects of corrosion caused by the environment. HELIOS 3 FASTENERS aims to prevent delayed component fracture through quality control of galvanized batches.

HELIOS 3 FASTENERS can be also used to estimate the diffusible hydrogen concentration adsorbed by the galvanized components of brake line terminals and connectors. The furnace temperature can be set to 180°C. Incorrect galvanization of brake line terminals can cause hydrogen leakage into the brake fluid, leading to an extended brake lever travel, decreased braking capacity, and increased risk of accidents.

Letomec can provide a customized solution based on the dimensions of the customer's samples.

The HELIOS Platform including HELIOS 3-FASTENERS is coverd by the Patent N. EP 2912452 B1.

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