• Aucun résultat trouvé

Comparison of two hot cracking tests JWRI and CRW


Academic year: 2021

Partager "Comparison of two hot cracking tests JWRI and CRW"


Texte intégral


HAL Id: hal-02442274


Submitted on 16 Jan 2020

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Comparison of two hot cracking tests JWRI and CRW Y. Gao, O. Asserin, D. Ayrault, O. Fandeur, M. Ronfard-Haret, D. Solas, P.


To cite this version:

Y. Gao, O. Asserin, D. Ayrault, O. Fandeur, M. Ronfard-Haret, et al.. Comparison of two hot cracking tests JWRI and CRW. FEMS Junior Euromat 2016, Jul 2016, Lausanne, Switzerland. �hal-02442274�


Numerical Simulation JWRI & CRW

Conclusions and further works

Comparison of two hot cracking tests JWRI and CRW





• Compare hot cracking tests for different welding processes, TIG and Laser, using 316L(N) stainless steel alloy

• Develop simulation of type CAFE (Cellular Automaton Finite Element) in order to predict granular structures in welds with the help of metallographic observations + EBSD

• Identify the high temperature behavior law with the help of Gleeble simulator tests

• Develop numerical simulations of hot cracking tests to identify a hot cracking thermomechanical criterion


Contact: yuan.gao@cea.fr


Solidification hot cracking

may be encountered when

welding 316L(N) using its

filler metals. This material

is used for the reactor


Hot cracking is not allowed in

welds according to the rules of

construction and design of

nuclear components

It requires :

• to prevent this risk

• to ensure that the material

exhibits a satisfactory


• Propose a hot cracking test which realizes the tradeoff between sensitivity and robustness :

sensitivity to differentiate the nuances of the material and to propose a thermomechanical

hot cracking criterion ;

robustness to avoid the operatives uncertainties and get in repeatability conditions.

• Improve the understanding of hot cracking mechanisms and to identify a

thermomechanical hot cracking criterion by means of the numerical simulation of hot

cracking tests.

• Characterize granular structures around the crack areas to couple multiscale approaches

such as CAFE (Cellular Automata Finite Element) for the prediction of the grain structures

with the thermomechanical behavior of the mushy zone.

JWRI test

Restraint test - CRW

Free restraint test - JWRI

JWRI (Joining and Welding Research Institute) test Maintaining of specimen Trapezoidal specimen Gas backside

protection Welding torch

2D simulated temperature field with the hot crack

JWRI test allows :

• to observe a crack arrest • to analyze hot cracking


• to identify a crack arrest criterion

Comparing the simulation results to the experimental data from the literature [1]

[1] N. CONIGLIO, M. PATRY. Science and Technology of Welding and Joining, vol. 18, No 7, p. 573-580, 2013.

Yuan GAO


, Olivier ASSERIN


, Danièle AYRAULT


, Olivier FANDEUR




, Denis SOLAS


, Philippe PILVIN



CEA, DEN, DANS, DM2S, SEMT, LTA, 91191 Gif-sur-Yvette, France


CEA, DEN, DANS, DM2S, SEMT, LM2S, 91191 Gif-sur-Yvette, France


Université de Bretagne-Sud, LIMATB>IRDL, Rue Saint-Maudé, 56321 Lorient, France


Université de Paris-Sud, ICMMO, Rue du Doyen Georges Poitou, 91405 Orsay, France

IV generation nuclear reactor SFR (Sodium Fast Reactor)

2D simulated stress field


x y

Stress along Y at 8s

JUNIOR EUROMAT July 10-14 2016

Hot cracking in welding

CRW (Controlled Restraint Weldability) test [1]

Advantage of CRW test • both initiation and

arresting crack

Numerical simulation of this test

• Understand local mechanisms of hot

cracking and to identify a hot crack initiation


The preferential growth direction is the

<100> direction that is aligned with the

temperature gradient

Metallographic observations and experimental results

Structure of the welding seam for elliptical bath

(a): epitaxial grains growing near the fusion line

(b): competitive growth between grains in the melting zone

Micrograph of the epitaxial area Base metal Molten zone Undersides

Sample for the analysis of the cracked part


Sample for the analysis of the non cracked part


cracking Welding direction Observation direction

EBSD cartographic for test for (a)

Welding direction

Energy balance: ρ𝐶𝑝 𝜕𝑇

𝜕𝑡 = −𝑑𝑖𝑣 −𝑘𝑔𝑟𝑎𝑑𝑇 + 𝑤

ρ : material density

𝐶𝑝 : specific heat capacity 𝑇 : temperature

𝑘 : thermal conductivity 𝑤 : volumic heat sources Material : aluminum alloy 6061 Welding process : laser

Stress along Y with a restraint of 86 MPa at point P3 over time

-150 -100 -50 0 50 100 150 200 250 0 2 4 6 8 10 0 200 400 600 800 1000 C o nt ra int e Y Y T em pé ra tu re ( °C )

Contrainte YY avec un chargement 86MPa sur la point P3 de l'éprouvette en fonction du temps

'smy86pa3.csv' u 1:2 'T86pa3.csv' u 1:2


Blue curve : temperature at point P3 over time Violet curve: stress along Y at point P3 over time

St ress alo n g Y (MP a) Temp er at u re (° C)

The equivalent source :

𝑤 𝑚, 𝑡 = 𝐴𝑒𝑥𝑝 −3 𝑥𝑓

2 + 𝑦 𝑓2


𝐴 : power dissipated in the Gaussian 𝑟 : radius of flux distribution


(a) (b)

Top view : (a) 𝑉𝑠 = 150 𝑚𝑚/𝑚𝑖𝑛; (b) 𝑉𝑠 = 80 𝑚𝑚/𝑚𝑖𝑛






, observation axial grain

Se ns d e s o ud ag e 𝜺𝒂 𝜺𝒃

Mechanical modeling (elastic -plastic constitutive law + thermal expansion) : Hooke’s law: σ𝑖𝑗 = μ ε𝑖𝑗𝑒 + 𝜐 1 − 2𝜐 𝑡𝑟(ε𝑒)δ𝑖𝑗 𝑎𝑛𝑑 μ = (1+υ)𝐸(𝑇) Strain decomposition : ε𝑖𝑗 = ε𝑖𝑗𝑒 + ε𝑖𝑗𝑝 + ε𝑖𝑗𝑡ℎ Plastic flow : ε𝑖𝑗𝑝 = λ 𝜕𝑓(σ𝜕σ 𝑖𝑗) 𝑖𝑗 Thermal expansion : ε𝑖𝑗𝑡ℎ=α(𝑇 − 𝑇0) δ𝑖𝑗

Evolution of the stress along Y between the liquidus temperature and the solidus temperature at different

points of the specimen

-20 -15 -10 -5 0 5 10 15 20 2 3 4 5 6 7 8 9 C o n tra in te YY en tre la T liq et T so l ( M Pa ) Temps (s)

Contrainte YY entre la Tliq et Tsol avec condition soudage A en 86MPa

'smyy1.csv' u 1:2 'smyy2.csv' u 1:2 'smyy3.csv' u 1:2 'smyy4.csv' u 1:2 'smyy5.csv' u 1:2 'smyy6.csv' u 1:2 'smyy7.csv' u 1:2 'smyy8.csv' u 1:2 'smyy9.csv' u 1:2 'smyy10.csv' u 1:2 'smyy11.csv' u 1:2 'smyy12.csv' u 1:2 'smyy13.csv' u 1:2 'smyy14.csv' u 1:2 'smyy15.csv' u 1:2 'smyy16.csv' u 1:2 'smyy17.csv' u 1:2 'smyy18.csv' u 1:2 P1 P2 P6 P8 P9 P10 P11 P12 P13 P174 P15 P16 P17 P18

Stress along Y with a restraint of 86 MPa between Tliq and Tsol

St ress alo n g Y b et w ee n Tliq an d T sol (MP a) Zone fissurée expérimentale [1] P3 P4 P5 P7

2D simulated temperature field

Temperature at 8s


Documents relatifs

Effect of ionic liquids on the structural, thermal and in vitro degradation properties of poly(ϵ-caprolactone) synthesized in the presence of Candida antarctica lipase..

Discrete Simulation of Sound Propagation in the City Based on Cellular Automaton.. Eloi Keita, Valéry Monthé,

• The CIS local ion measurements have been also correlated with global images of the plasmasphere, obtained by the EUV instrument onboard Image [4], for an event where the

le Soudage, le CND et l’Industrie des Matériaux et Alliages (IC-WNDT-MI’12) Oran du 26 au 28 Novembre 2012, http://www.csc.dz/ic-wndt-mi12/index.php 114 Figure 7: Variation

In this context, we studied law cracking of internal pressure pipe of super martensitic stainless steel 13% Cr and 5% Ni 2% Mo by a simulation using a finite element code

Using univariate analysis of 16 electrophysiological parameters (AP meas- urements, passive properties, excitability, etc…) and multivariate analyses (AHC and PCA) of 8

It is a well-known fact that one may turn finite Q-metric spaces into a Fra¨ıss´e class in a countable relational language (by adding a binary predicate for each pos- sibel value of

Neumann or Robin boundary conditions â First results with a mixed formulation Dynamic equation : heat equation. Michel Duprez Rule of the mesh in the Finite Element