https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Tue, 16 Jun 2026 00:08:43 GMT 2026-06-16T00:08:43Z http://hdl.handle.net/10985/9418 Towards Establishment of Weldability Test Standards for Hydrogen Assisted Cold Cracking KURJI, Rahim; CONIGLIO, Nicolas Industry and research have long desired the establishment of standards for weldability testing in regards to hydrogen assisted cold cracking formation. This would have the obvious advantage of allowing data to be reliably compared between different research labs. But making decisions regarding standards requires some careful thought and agreement on i) how test parameters affect test results, ii) what exactly needs to be measured, and iii) how test results should be interpreted and reported. Our depth of understanding on these points has matured significantly over time and, while there is not always universal agreement, it is at least possible to start highlighting factors important to standards. This paper examines these factors, including the welding parameters, restraint, hydrogen, and cracking index. When comparing different alloys having different thermal characteristics, the use of constant welding parameters (common practice) will result in variable weld penetration and weld pool shape, which can influence grain shape and microstructural features, which can result in inequitable weldability comparisons. Welding on test coupons having different dimensions can affect restraint, which will influence the residual stresses around the weldment. High restraint usually results in higher crack susceptibility. Also, hydrogen content present in a weldment depends on the thermal history, welding parameters, and surrounding atmosphere humidity; with high hydrogen contents associated to great cracking susceptibility. Finally, the selection of an appropriate cracking index is required for data analysis. Quantifications of crack length and minimum preheat temperature are common indexes used for comparison. Critical stress and hydrogen content are other indexes. But how well these indexes actually represent weldability are contentious issues. This paper will examine and quantify these issues in detail, thus providing the reader with an appreciation of all things that must be considered when preparing a standardized procedure for weldability testing. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9418 2015-01-01T00:00:00Z KURJI, Rahim CONIGLIO, Nicolas Industry and research have long desired the establishment of standards for weldability testing in regards to hydrogen assisted cold cracking formation. This would have the obvious advantage of allowing data to be reliably compared between different research labs. But making decisions regarding standards requires some careful thought and agreement on i) how test parameters affect test results, ii) what exactly needs to be measured, and iii) how test results should be interpreted and reported. Our depth of understanding on these points has matured significantly over time and, while there is not always universal agreement, it is at least possible to start highlighting factors important to standards. This paper examines these factors, including the welding parameters, restraint, hydrogen, and cracking index. When comparing different alloys having different thermal characteristics, the use of constant welding parameters (common practice) will result in variable weld penetration and weld pool shape, which can influence grain shape and microstructural features, which can result in inequitable weldability comparisons. Welding on test coupons having different dimensions can affect restraint, which will influence the residual stresses around the weldment. High restraint usually results in higher crack susceptibility. Also, hydrogen content present in a weldment depends on the thermal history, welding parameters, and surrounding atmosphere humidity; with high hydrogen contents associated to great cracking susceptibility. Finally, the selection of an appropriate cracking index is required for data analysis. Quantifications of crack length and minimum preheat temperature are common indexes used for comparison. Critical stress and hydrogen content are other indexes. But how well these indexes actually represent weldability are contentious issues. This paper will examine and quantify these issues in detail, thus providing the reader with an appreciation of all things that must be considered when preparing a standardized procedure for weldability testing. http://hdl.handle.net/10985/10822 Weld pool surface temperature measurement from polarization state of thermal emission MATHIEU, A.; AUBRETON, O.; STOLZ, C.; CONIGLIO, Nicolas This paper presents a passive polarimetry method using a division of aperture optical device in order to measure the temperature distribution at the weld pool surface. Thermal emission from a hot liquid metal was investigated at a near-infrared wavelength corresponding to a blind spectral window of a helium plasma generated during gas tungsten arc welding process. The refractive index of liquid metal and the surface radiance are deduced from the polarisation state of thermal emissions. Based upon the knowledge of both characteristics, the temperature distribution can be calculated. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/10822 2016-01-01T00:00:00Z MATHIEU, A. AUBRETON, O. STOLZ, C. CONIGLIO, Nicolas This paper presents a passive polarimetry method using a division of aperture optical device in order to measure the temperature distribution at the weld pool surface. Thermal emission from a hot liquid metal was investigated at a near-infrared wavelength corresponding to a blind spectral window of a helium plasma generated during gas tungsten arc welding process. The refractive index of liquid metal and the surface radiance are deduced from the polarisation state of thermal emissions. Based upon the knowledge of both characteristics, the temperature distribution can be calculated. http://hdl.handle.net/10985/12014 Investigating surface roughness of ZE41 magnesium alloy cast by low-pressure sand casting process SANITAS, Antonin; BEDEL, Marie; EL MANSORI, Mohamed; CONIGLIO, Nicolas The sand mold 3D printing technologies enable the manufacturing of molds with great dimensional accuracy. However, the roughness of as-cast components is higher when cast in a 3D printed mold rather than in a traditional sand mold. Coating the inner cavity is an efficient solution but can be costly and, in the narrowest cavities, not achievable. Finding a procedure to reduce the as-cast roughness without coating would ease the casting procedures. In the present work, surface analysis of ZE41 magnesium alloy is presented after being cast in 3D printed furan sand molds without coating using the low-pressure casting process. The molten metal temperature was measured during casting at different positions along the cast cavity. The as-cast surface roughness was correlated to the molten metal temperature and solid fraction at the time of contact against the sand mold surface. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/12014 2017-01-01T00:00:00Z SANITAS, Antonin BEDEL, Marie EL MANSORI, Mohamed CONIGLIO, Nicolas The sand mold 3D printing technologies enable the manufacturing of molds with great dimensional accuracy. However, the roughness of as-cast components is higher when cast in a 3D printed mold rather than in a traditional sand mold. Coating the inner cavity is an efficient solution but can be costly and, in the narrowest cavities, not achievable. Finding a procedure to reduce the as-cast roughness without coating would ease the casting procedures. In the present work, surface analysis of ZE41 magnesium alloy is presented after being cast in 3D printed furan sand molds without coating using the low-pressure casting process. The molten metal temperature was measured during casting at different positions along the cast cavity. The as-cast surface roughness was correlated to the molten metal temperature and solid fraction at the time of contact against the sand mold surface. http://hdl.handle.net/10985/18800 Effect of weld travel speed on solidification cracking behavior. Part 3: modeling CROSS, C. E.; CONIGLIO, Nicolas Solidification cracking is a weld defect common to certain susceptible alloys rendering many of them unweldable. It forms and grows continuously behind a moving weld pool within the two-phase mushy zone and involves a complex interaction between thermal, metallurgical, and mechanical factors. Research has demonstrated the ability to minimize solidification cracking occurrence by using appropriate welding parameters. Despite decade’s long efforts to investigate weld solidification cracking, there remains a lack of understanding regarding the particular effect of travel speed. While the use of the fastest welding speed is usually recommended, this rule has not always been confirmed on site. Varying welding speed has many consequences both on stress cells surrounding the weld pool, grain structure, and mushy zone extent. Experimental data and models are compiled to highlight the importance of welding speed on solidification cracking. This review is partitioned into three parts: part I focuses on the effects of welding speed on weld metal characteristics, part II reviews the data of the literature to discuss the importance of selecting properly the metrics, and part III details the different methods to model the effect of welding speed on solidification cracking occurrence. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18800 2020-01-01T00:00:00Z CROSS, C. E. CONIGLIO, Nicolas Solidification cracking is a weld defect common to certain susceptible alloys rendering many of them unweldable. It forms and grows continuously behind a moving weld pool within the two-phase mushy zone and involves a complex interaction between thermal, metallurgical, and mechanical factors. Research has demonstrated the ability to minimize solidification cracking occurrence by using appropriate welding parameters. Despite decade’s long efforts to investigate weld solidification cracking, there remains a lack of understanding regarding the particular effect of travel speed. While the use of the fastest welding speed is usually recommended, this rule has not always been confirmed on site. Varying welding speed has many consequences both on stress cells surrounding the weld pool, grain structure, and mushy zone extent. Experimental data and models are compiled to highlight the importance of welding speed on solidification cracking. This review is partitioned into three parts: part I focuses on the effects of welding speed on weld metal characteristics, part II reviews the data of the literature to discuss the importance of selecting properly the metrics, and part III details the different methods to model the effect of welding speed on solidification cracking occurrence. http://hdl.handle.net/10985/18799 Effect of weld travel speed on solidification cracking behavior. Part 2: testing conditions and metrics CROSS, C. E.; CONIGLIO, Nicolas Solidification cracking is a weld defect common to certain susceptible alloys rendering many of them unweldable. It forms and grows continuously behind a moving weld pool within the two-phase mushy zone and involves a complex interaction between thermal, metallurgical, and mechanical factors. Research has demonstrated the ability to minimize solidification cracking occurrence by using appropriate welding parameters. Despite decade’s long efforts to investigate weld solidification cracking, there remains a lack of understanding regarding the particular effect of travel speed. While the use of the fastest welding speed is usually recommended, this rule has not always been confirmed on site. Varying welding speed has many consequences both on stress cells surrounding the weld pool, grain structure, and mushy zone extent. Experimental data and models are compiled to highlight the importance of welding speed on solidification cracking. This review is partitioned into three parts: part I focuses on the effects of welding speed on weld metal characteristics, part II reviews the data of the literature to discuss the importance of selecting properly the metrics, and part III details the different methods to model the effect of welding speed on solidification cracking occurrence. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18799 2020-01-01T00:00:00Z CROSS, C. E. CONIGLIO, Nicolas Solidification cracking is a weld defect common to certain susceptible alloys rendering many of them unweldable. It forms and grows continuously behind a moving weld pool within the two-phase mushy zone and involves a complex interaction between thermal, metallurgical, and mechanical factors. Research has demonstrated the ability to minimize solidification cracking occurrence by using appropriate welding parameters. Despite decade’s long efforts to investigate weld solidification cracking, there remains a lack of understanding regarding the particular effect of travel speed. While the use of the fastest welding speed is usually recommended, this rule has not always been confirmed on site. Varying welding speed has many consequences both on stress cells surrounding the weld pool, grain structure, and mushy zone extent. Experimental data and models are compiled to highlight the importance of welding speed on solidification cracking. This review is partitioned into three parts: part I focuses on the effects of welding speed on weld metal characteristics, part II reviews the data of the literature to discuss the importance of selecting properly the metrics, and part III details the different methods to model the effect of welding speed on solidification cracking occurrence. http://hdl.handle.net/10985/18544 Designing metallic surfaces in contact with hardening fresh concrete: A review SPITZ, N.; EL MANSORI, Mohamed; CONIGLIO, Nicolas Concrete, a commonly used material in the construction industry, interacts with metallic surfaces such as formwork during pouring and reinforced bar during lifespan. Formworks are designed to minimize hardened concrete adherence in order to avoid wall defects after formwork removal. In opposite, reinforced bar designs aim at maximizing their adherence to concrete for optimizing the transmission of mechanical solicitations. The present review investigates the surface properties that govern bonding of freshly poured concrete onto metallic surfaces. Identifying the underlying mechanisms of adhesion highlighted the importance of substrate characteristics (roughness, composition), concrete curing and compaction), and interfacial additives (release agents, wetting). This paper addresses the basic requirements in designing a functional surface interacting with concrete and emphasizes today challenges. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18544 2020-01-01T00:00:00Z SPITZ, N. EL MANSORI, Mohamed CONIGLIO, Nicolas Concrete, a commonly used material in the construction industry, interacts with metallic surfaces such as formwork during pouring and reinforced bar during lifespan. Formworks are designed to minimize hardened concrete adherence in order to avoid wall defects after formwork removal. In opposite, reinforced bar designs aim at maximizing their adherence to concrete for optimizing the transmission of mechanical solicitations. The present review investigates the surface properties that govern bonding of freshly poured concrete onto metallic surfaces. Identifying the underlying mechanisms of adhesion highlighted the importance of substrate characteristics (roughness, composition), concrete curing and compaction), and interfacial additives (release agents, wetting). This paper addresses the basic requirements in designing a functional surface interacting with concrete and emphasizes today challenges. http://hdl.handle.net/10985/18718 Features selection approaches for an objective control of cosmetic quality of coated surfaces BESSONNET, S; EL MANSORI, Mohamed; MEZGHANI, S; PEE, R; PINAULT, S; CONIGLIO, Nicolas The cosmetic aspect is one of the main functions of industrial surfaces in numerous applications. Even the smallest surface defects may have a critical effect on the cosmetic tolerability of such industrial surfaces. Thus, surfaces are generally coated at the last manufacturing process stage to cover existing defects and to certify their cosmetic quality. The surface quality is however constantly controlled after coating that induces an increase of lead-time increase and production costs. This is due to a various flaw patterns and a lack of uncoated surfaces specifications. Hence, the identification of relevant surface morphological parameters underlies an objective and automatic cosmetic control performance. In fact, this relevant parameter selection allows tracking surface flaws during the coating finishing operation. This paper presents a comprehensive overview of various feature selection tools for data analysis (Neighbourhood Component Analysis (NCA), ReliefF, Sequential wrapper method, Decision tree) to extract relevant information out of physical data. A design of experiment based on scratches test on amorphous polymers to generate typical controlled defects has been performed. Then, several cosmetic defects characteristics were extracted from experimental measurements. Feature selection approaches were applied and compared to determine the most relevant parameters. The advantages and limitations of each method for data analysis have been highlighted in the case of real engineering surface quality control. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18718 2020-01-01T00:00:00Z BESSONNET, S EL MANSORI, Mohamed MEZGHANI, S PEE, R PINAULT, S CONIGLIO, Nicolas The cosmetic aspect is one of the main functions of industrial surfaces in numerous applications. Even the smallest surface defects may have a critical effect on the cosmetic tolerability of such industrial surfaces. Thus, surfaces are generally coated at the last manufacturing process stage to cover existing defects and to certify their cosmetic quality. The surface quality is however constantly controlled after coating that induces an increase of lead-time increase and production costs. This is due to a various flaw patterns and a lack of uncoated surfaces specifications. Hence, the identification of relevant surface morphological parameters underlies an objective and automatic cosmetic control performance. In fact, this relevant parameter selection allows tracking surface flaws during the coating finishing operation. This paper presents a comprehensive overview of various feature selection tools for data analysis (Neighbourhood Component Analysis (NCA), ReliefF, Sequential wrapper method, Decision tree) to extract relevant information out of physical data. A design of experiment based on scratches test on amorphous polymers to generate typical controlled defects has been performed. Then, several cosmetic defects characteristics were extracted from experimental measurements. Feature selection approaches were applied and compared to determine the most relevant parameters. The advantages and limitations of each method for data analysis have been highlighted in the case of real engineering surface quality control. http://hdl.handle.net/10985/18798 Effect of weld travel speed on solidification cracking behavior. Part 1: weld metal characteristics CROSS, C. E.; CONIGLIO, Nicolas Solidification cracking is a weld defect common to certain susceptible alloys rendering many of them unweldable. It forms and grows continuously behind a moving weld pool within the two-phase mushy zone and involves a complex interaction between thermal, metallurgical, and mechanical factors. Research has demonstrated the ability to minimize solidification cracking occurrence by using appropriate welding parameters. Despite decade’s long efforts to investigate weld solidification cracking, there remains a lack of understanding regarding the particular effect of travel speed. While the use of the fastest welding speed is usually recommended, this rule has not always been confirmed on site. Varying welding speed has many consequences both on stress cells surrounding the weld pool, grain structure, and mushy zone extent. Experimental data and models are compiled to highlight the importance of welding speed on solidification cracking. This review is partitioned into three parts: part I focuses on the effects of welding speed on weld metal characteristics, part II reviews the data of the literature to discuss the importance of selecting properly the metrics, and part III details the different methods to model the effect of welding speed on solidification cracking occurrence Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18798 2020-01-01T00:00:00Z CROSS, C. E. CONIGLIO, Nicolas Solidification cracking is a weld defect common to certain susceptible alloys rendering many of them unweldable. It forms and grows continuously behind a moving weld pool within the two-phase mushy zone and involves a complex interaction between thermal, metallurgical, and mechanical factors. Research has demonstrated the ability to minimize solidification cracking occurrence by using appropriate welding parameters. Despite decade’s long efforts to investigate weld solidification cracking, there remains a lack of understanding regarding the particular effect of travel speed. While the use of the fastest welding speed is usually recommended, this rule has not always been confirmed on site. Varying welding speed has many consequences both on stress cells surrounding the weld pool, grain structure, and mushy zone extent. Experimental data and models are compiled to highlight the importance of welding speed on solidification cracking. This review is partitioned into three parts: part I focuses on the effects of welding speed on weld metal characteristics, part II reviews the data of the literature to discuss the importance of selecting properly the metrics, and part III details the different methods to model the effect of welding speed on solidification cracking occurrence http://hdl.handle.net/10985/20876 Characterizing tribological behavior of fresh concrete against formwork surfaces SPITZ, N.; CONIGLIO, Nicolas; LIBESSART, L.; EL MANSORI, Mohamed; DJELAL, C. The friction of concrete on the interior skin of formworks takes place during the pouring of concrete into the molds. The present work investigates the friction of a granular material (i.e. fresh concrete) against metallic and polymeric surfaces. Interfacial behavior between different formulated concretes and formwork skins is characterized using a plane-plane tribometer dedicated to concrete tribometer. The formwork surface is measured before and after testing to quantify the wear issue. A Coulomb friction law is observed within the range of tested normal pressures. Tribological tests reveal that friction mechanisms depend on the interface properties. Two underlying mechanisms are hypothesized to explain the wearing of the formwork skin: a granulate-formwork solid-solid friction and a capillary-dominated friction. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/20876 2021-01-01T00:00:00Z SPITZ, N. CONIGLIO, Nicolas LIBESSART, L. EL MANSORI, Mohamed DJELAL, C. The friction of concrete on the interior skin of formworks takes place during the pouring of concrete into the molds. The present work investigates the friction of a granular material (i.e. fresh concrete) against metallic and polymeric surfaces. Interfacial behavior between different formulated concretes and formwork skins is characterized using a plane-plane tribometer dedicated to concrete tribometer. The formwork surface is measured before and after testing to quantify the wear issue. A Coulomb friction law is observed within the range of tested normal pressures. Tribological tests reveal that friction mechanisms depend on the interface properties. Two underlying mechanisms are hypothesized to explain the wearing of the formwork skin: a granulate-formwork solid-solid friction and a capillary-dominated friction. http://hdl.handle.net/10985/23608 Nano-wear-induced behavior of selective laser melting commercial pure titanium KANG, Nan; EL MANSORI, Mohamed; CONIGLIO, Nicolas; CODDET, Christian In this work, the nano-wear-induced behavior of selective laser melting (SLM) processed commercial pure titanium was investigated under several applied loads from 1 mN to 100 mN. The dense (over 99%) commercial pure titanium sample was manufactured using SLM process with optimized process parameters (900 J m-1). Nano-wear testing was performed on the polished surface of SLM processed commercial pure titanium. The friction coefficient increased from 0.04 to 0.9 as the load increased from 1 mN to 100 mN. Additionally, the sliding behavior changed along with the applied loads, from elastic to plastic and unstable friction behaviors. The elastic-plastic transition appeared at applied load of 50 mN, which was also confirmed by the calculation results. While the applied load ranged between 50 mN and 80 mN (plastic friction), the average friction coefficient was light smaller than that of the macroscopic ball-on-disc test. During the sliding, a friction vibration appeared and its mechanism was also investigated and discussed combine the wear surface morphologies. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/23608 2018-01-01T00:00:00Z KANG, Nan EL MANSORI, Mohamed CONIGLIO, Nicolas CODDET, Christian In this work, the nano-wear-induced behavior of selective laser melting (SLM) processed commercial pure titanium was investigated under several applied loads from 1 mN to 100 mN. The dense (over 99%) commercial pure titanium sample was manufactured using SLM process with optimized process parameters (900 J m-1). Nano-wear testing was performed on the polished surface of SLM processed commercial pure titanium. The friction coefficient increased from 0.04 to 0.9 as the load increased from 1 mN to 100 mN. Additionally, the sliding behavior changed along with the applied loads, from elastic to plastic and unstable friction behaviors. The elastic-plastic transition appeared at applied load of 50 mN, which was also confirmed by the calculation results. While the applied load ranged between 50 mN and 80 mN (plastic friction), the average friction coefficient was light smaller than that of the macroscopic ball-on-disc test. During the sliding, a friction vibration appeared and its mechanism was also investigated and discussed combine the wear surface morphologies.