Welding and Heat Treatment Steel industry · 2014-11-05 · Crack propagates under the effect of...

Copyright © ESI Group, 2009. All rights reserved. 1

Welding and Heat Treatment

in

Steel industry

Modeling Techniques and Applications

Philippe MOURGUE ESI-France

16 October 2014


AGENDA

STEEL Material - Metallurgy

Heat Treatment application

Welding application

Copyright © ESI Group, 2009. All rights reserved.

distorsion history during quenching period

Quenching of a gear

WHY SUCH BEHAVIOR ?


Thermal & MetallurgicalProperties

Thermal properties versus to temperature (T°c) and according to the considered phases (zi)

Thermal conductivity : = f(T°c, zi)

Density : = f(T°c, zi)

Specific heat : Cp = f(T°c, zi)

Enthalpy : H = f(T°c, zi)

Latent Heat Effect : H = f(T°c, zi)

Metallurgical Kinetics of Transformation for different heating and cooling rate

Austenitic Transformation : Z = f(T °c, dT/dt)

Ferrite Transformation : Zf = f(T °c, dT/dt)

Bainite Transformation : Zb = f(T °c, dT/dt)

Martensite Transformation : Zm = f(T °c)


MODELISATION

CCT Diagram Transformations de phase (acier)

Evolution d’état

-0,4

0

0,4

0,8

1,2

1,6

0 400 800

Température [°C]

Défo

rmati

on [

%]

Phase

Phase

Body-centered

cubic

Face-centered

cubic

Austenite Transformation

Martensite Transformation

Cooling Rate

dT/dt = -15°C/s

-0,4

0

0,4

0,8

1,2

1,6

0 400 800

Température [°C]

Défo

rmati

on [

%]

Phase

Phase

Body-centered

cubic

Face-centered

cubic

Austenite Transformation

Martensite Transformation

Cooling Rate

dT/dt = -15°C/s

Yield Stress vs

Temperature

for each phases.


Mechanical Properties

Mechanical properties versus to temperature (T°c) and

according to the considered phases (zi) Young’s modulus : E = f(T°c, zi)

Poisson coefficient : = f(T°c, zi)

Thermal strains : th = f(T°c, zi)

Yield stress : = f(T°c, zi)

Strain hardening : h = f(T°c, zi)

Viscous parameter

Hardening Coefficient : K = f(T°c, zi)

Hardening Exponent : m = f(T°c, zi)

Strain Rate Sensitive Exponent : n = f(T°c, zi)


MODELES PHYSIQUE

SYSWELD permet un couplage fort entre la Thermique

et la Métallurgie

Diffusion - Précipitations

Electromagnétisme

Analyses Mécaniques

Analyse Thermique

Metallurgie

Dissipated Joule Energy

Temperatures

Temperatures Temperatures Phase Proportions

Temperatures Latent Heat Phase Proportions

Chemical Composition Precipitations

Chemical Composition Precipitations

Deformation- energy

Stresses


METALLURGICAL PHENOMENON

Température

Transformation Martensitique

Transformation Bainitique

Transformation Austénitique

Déformations

Contraintes


HEAT TREATMENT APPLICATIONS

9


distorsion history during quenching period

Quenching of a gear


Nozzle HyperQuench

Objectives: Residual stresses and deformation after

treament, machining and structural analysis


Thermal evolution during HT

Nozzle Hypertremp

Von mises stress after HT and Machining


Stresses at skin: Mesures Simulation

Nozzle HyperQuench


WELDING APPLICATIONS

14


Transient Welding Modeling

Heat source adjustment

0

200

400

600

800

1000

1200

1400

0 1 2 3 4 5 6 7

Position (mm)

tem

pera

ture

(°C

)

Experiment

Simulation


Various methodologies

for various expectations



Single Pass process

1: Transient temperature field

2: Final distortion

3: Residual stresses

1

3

2



A more complex welding sequence

Distortion



Multi-Pass Welding

Temperature

Distortion


Multi pass welding:

Thermal /metallurgical

/mechanical analysis

Thermal analysis

during each of the 30

welding pass taking

into account

convection and

radiation

Stress analysis during

welding sequences

Nozzle repair

Residual stress analysis

Drain/ Instrumentation Nozzle

Predifined Goldak heat source

SYSWELD Courtesy Doosan

20

Realistic ‘as-built’ model


Heat treatment:

Heat convection and

radiation

Stress released after

Post Weld Heat

Treatment (PWHT)

Nozzle repair

Residual stress analysis

SYSWELD

Courtesy Doosan

21


CTC

24

Examples & proofs from ship building (CTC) & railway (Maglev)

Tool

bars

Output

Console

Original position

Measured distortion

Predicted distortion

Distorted Structure SYSWELD Predictions Validation Plot

Example of Shipbuilding Application (Courtesy CTC)


ITER: Local-Global


Welding simulation for

Process optimisation

Stamping, Heat Treatment and Welding

Huge Thick Walled Designs



Multi-Pass Welding


ITER Vacuum Vessel Welding

ITER project – Vacuum vessel electron beam welding assembly

1 of the 9 sectors of the ITER vacuum vessel

VEC mock-up

Rolling the inner and outer shell

Machining the housing holes

Welding the components together SYSWELD

31


Distortion validation

Key welding results

Circular EB welds

32


Clamping effects


Fatigue life

Courtesy PSA

Congres NAFEM France – 12 Octobre 2010


Cold cracking

Hydrogen impact


Cold cracking

Welding of a Dissimilar weld

Electron beam process

Hydrogen diffusion

Crack initiation and propagation

3 Materials + molten zone

MATERIAL_1

MATERIAL_3

MATERIAL_2

Case study :

•26 months in storage conditions

•Pressure test

Initial H content


Welding simulation

3D axial symmetric model By Steady state method on 340 degrees

By a transient method to simulate the end of welding


Welding simulation 3D

By a transient method to simulate the weld recovery

area (3 degrees)

3°


Mechanical results

Slope area Hoops stresses

Crack opening stress

Copyright © ESI Group, 2009. All rights reserved. 46 46

Hydrogen concentration

Cumulative plastic strain

Iso H2 concentration after

welding and 1 during year

storage

Initial H2

content

H2 properties depend on

Température and Plastic

Strains

Hydrogen diffusion


Crack propagation

26 months In storage conditions

Crack propagates under the effect of welding residual stresses

and hydrogen embrittlement

a = 0 if J ≤ Jc kJ/m²

a = 0.5 mm where J = Jmax along the front

Ho

op

str

esses

Cu

mu

lati

ve

pla

sti

c s

tra

ins

H1

H2

a

J

Plastic strains developed at the

crack front


Crack propagation

In storage conditions

Crack propagates under the effect of welding residual

stresses and hydrogen embrittlement

Compressive

hoop stresses

Decreasing

tensile

hoop

stresses

From 0 to 26 months


Crack propagation

Hydro test simulation

Predicted crack

front

The wall is now

perforated


Couple mechanical results and hydrogen diffusion to capture the crack

propagation kinetic

Requires a better characterization of H diffusion to consider trapping effect

3D modeling of H diffusion and averaging of values in the first ring of elements

could be done in order to smooth numerical singularity

Possibility to check the stability of an open crack

Simulation of the pressure test with a crack open

Simulate the same crack behavior in real flight conditions

Requires the definition of flight loads

Do not require any new material characterization as the crack tip is out of the HAZ

Conclusions

Delivered Value


Thank You

You

Product, processes, knowledge, engineering

Simulation

Helps to improve engineering

You & Simulation Engineering

Cost reduction & Quality improvement

Simulation makes engineering more transparent

Welding and Heat Treatment Steel industry · 2014-11-05 · Crack propagates under the effect of...

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Transcript of Welding and Heat Treatment Steel industry · 2014-11-05 · Crack propagates under the effect of...