Periodic Reporting for period 2 - H2Free (Investigation and modelling of Hydrogen effusion in electrochemically plated ultra-high-strength-steels used for landing gear structures)
Période du rapport: 2022-04-01 au 2023-10-31
One drawback associated to Ultra High Strength Steels (UHSS) coated components is the risk of hydrogen embrittlement (HE) and delayed hydrogen fracture of the part. This problem has been tackled by developing LHE processes and by applying a degassing stage. The standard degassing process is applied equally to the components regardless UHSS or coating composition/morphology. However, it is known that the nature and structure of both the base material and the coating have a great influence in the hydrogen intake and degassing efficiency. As there are no experimental techniques to measure hydrogen content or HE in a specific part of a real component at an industrial environment, modelling and simulation approaches, developed with a strong experimental base, provided the keys to improve the process.
The main objective of the H2Free project was to develop a practical guideline for hydrogen degassing of UHS-steels plated with LHE-ZnNi, with the aim of saving production costs and allowing ZnNi to overtake Cd coatings.
H2Free developed and validated a model able to predict the H uptake during plating as well as the effusion rate during degassing at different temperature. Guidelines contained simple rules to provide criteria both for plating and degassing have been created as well as simple characterization techniques to evaluate the morphology of the produced coatings in industrial environment.
The main objective of the H2Free project was to develop a practical guideline for hydrogen degassing of UHS-steels plated with LHE-ZnNi, with the aim of saving production costs and allowing ZnNi to overtake Cd coatings.
H2Free developed and validated a model able to predict the H uptake during plating as well as the effusion rate during degassing at different temperature. Guidelines contained simple rules to provide criteria both for plating and degassing have been created as well as simple characterization techniques to evaluate the morphology of the produced coatings in industrial environment.
WP1: The project specifications and the investigations to create the model have been fully defined. A large number of specimens has been manufactured. The applicable standardization landscape has been analyzed.
WP2. ZnNi coatings have been obtained under different plating conditions on a high number of 300M specimens. The extended experimental activity allow the correlation among plating conditions, coatings characteristics and H content. Moreover, the H diffusion kinetics through the steels and the coatings with different morphologies has been evaluated at different degassing temperatures. Small punch tests and HE experiments according to ASTM F519 standard have been performed to correlate H content and mechanical properties.
WP3. A model to perform outgassing simulations of a 300M coated steel has been developed and validated. The model is developed with the finite element library Fenics and implemented with python scripting. A tool to generate martensite microstructure was developed for this project. Work on the initial conditions, mainly the hydrogen distribution profile was discussed. The model has been integrated in a 3D CAE tool (Elsyca Plating Manager). The model has been validated experimentally using a dedicated tool designed and fabricated in the project.
WP4: The same approach used in WP2 for ZnNi and Cd coatings on 300M steel was used for the coatings on E35NCD16H, Custom 465 and EZ2NKD8 steel. The obtained results have been used to adapt the model to the further studied steels. The model has been validated in laboratory scale.
WP5: Based on the experimental and modelling results, a series of practical rules to be applied at industrial environment aiming to minimize H uptake during plating and optimize degassing efficiency have been drafted. Simple characterization techniques which can easily be used in industrial environment have been developed to characterize the obtained coatings morphology. The model and the characterization techniques have been validated at industrial environment by plating on demonstrators and real parts.
WP6: Different technical articles have been published to technical magazines to promote the project. A total of 10 presentations have been performed to scientific conferences and one peer review article has been published. 3 more are under preparation and will be published after the end of the project. A dedicated workshop, open to wider public, has been organized presenting the model developed during the project.
WP2. ZnNi coatings have been obtained under different plating conditions on a high number of 300M specimens. The extended experimental activity allow the correlation among plating conditions, coatings characteristics and H content. Moreover, the H diffusion kinetics through the steels and the coatings with different morphologies has been evaluated at different degassing temperatures. Small punch tests and HE experiments according to ASTM F519 standard have been performed to correlate H content and mechanical properties.
WP3. A model to perform outgassing simulations of a 300M coated steel has been developed and validated. The model is developed with the finite element library Fenics and implemented with python scripting. A tool to generate martensite microstructure was developed for this project. Work on the initial conditions, mainly the hydrogen distribution profile was discussed. The model has been integrated in a 3D CAE tool (Elsyca Plating Manager). The model has been validated experimentally using a dedicated tool designed and fabricated in the project.
WP4: The same approach used in WP2 for ZnNi and Cd coatings on 300M steel was used for the coatings on E35NCD16H, Custom 465 and EZ2NKD8 steel. The obtained results have been used to adapt the model to the further studied steels. The model has been validated in laboratory scale.
WP5: Based on the experimental and modelling results, a series of practical rules to be applied at industrial environment aiming to minimize H uptake during plating and optimize degassing efficiency have been drafted. Simple characterization techniques which can easily be used in industrial environment have been developed to characterize the obtained coatings morphology. The model and the characterization techniques have been validated at industrial environment by plating on demonstrators and real parts.
WP6: Different technical articles have been published to technical magazines to promote the project. A total of 10 presentations have been performed to scientific conferences and one peer review article has been published. 3 more are under preparation and will be published after the end of the project. A dedicated workshop, open to wider public, has been organized presenting the model developed during the project.
H2Free project provides a unique combination of new scientific knowledge and mid-term technological impact. A deep knowledge of hydrogen diffusion and intake on coated UHSS parts has been generated. Techniques for detection of undesirable coating structures and fast method for HE probability have been developed to help industries in recognizing defects. A very complete computational tool for simulating hydrogen diffusion and hydrogen remaining content after a degassing process and coupled to a 3D tool for modelling coating characteristics depending on plating process conditions has been implemented and validated at industrial environment.
The progress beyond the state of the art is marked through the following project results:
1. Fast method to determine the H embrittlement of UHSS coated with ZnNi: LECO and GDOES have been used as techniques to evaluate the H content after plating and degassing.
2. Test results’ database and its conclusions: A database correlating plating parameters with coating morphology, thickness and H content has been created. The H effusion is related both to the initial H content and coating morphology.
3. Validated computer-based model to simulate H effusion
4. CAD-based simulation software platform including the coating morphology prediction and embedding H effusion model: The developed model has been coupled to a CAD-based simulation software platform and validated at industrial environment.
5. Simple non-destructive method for coating characterization. Different simple methods have been developed allowing a fast evaluation of the coating morphology over complex parts.
6. Guidelines for a plating procedure minimizing HE risk and for optimizing degassing have been draft.
7. A new device for controlling the galvanic processes has been developed during the project.
The H2Free outcomes have a strong industrial, scientific, and environmental impact. The main benefit is to have a practical guideline for hydrogen degassing of plated UHSS aiming on saving production costs and minimising environmental impact allowing ZnNi to overtake Cd coatings.
The progress beyond the state of the art is marked through the following project results:
1. Fast method to determine the H embrittlement of UHSS coated with ZnNi: LECO and GDOES have been used as techniques to evaluate the H content after plating and degassing.
2. Test results’ database and its conclusions: A database correlating plating parameters with coating morphology, thickness and H content has been created. The H effusion is related both to the initial H content and coating morphology.
3. Validated computer-based model to simulate H effusion
4. CAD-based simulation software platform including the coating morphology prediction and embedding H effusion model: The developed model has been coupled to a CAD-based simulation software platform and validated at industrial environment.
5. Simple non-destructive method for coating characterization. Different simple methods have been developed allowing a fast evaluation of the coating morphology over complex parts.
6. Guidelines for a plating procedure minimizing HE risk and for optimizing degassing have been draft.
7. A new device for controlling the galvanic processes has been developed during the project.
The H2Free outcomes have a strong industrial, scientific, and environmental impact. The main benefit is to have a practical guideline for hydrogen degassing of plated UHSS aiming on saving production costs and minimising environmental impact allowing ZnNi to overtake Cd coatings.