How can large-scale research facilities like ESS and

MAX IV help in understanding the microstructural

and corrosion properties of welds in stainless steels?

1

Mikael GrehkSandvik Materials Technology

2

The Sandvik group business areas – our portfolio

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10%

40%

63%

38%

29%

3

Share of revenues 2016 excl. Mining

systems and group activities

Share of adjusted operating profit 2016,

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Other operations (non-strategic assets)

contributed by 6% to revenues 2016

and 5% to adjusted operating profit 2016

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THE MATERIALS EVOLUTION SMTOUR CORE CAPABILITIES AND DNA

19301980

20082015

2020

Nickel based alloys

Powder metallurgy

Advanced stainless incl. duplex

Stainless steels

Carbon incl.drill steels

Super alloys*

*Alloys that require primary vacuum melting.

• UNIQUE EXPERTISE in advanced stainless steels

and special alloys for the most demanding industries.

• WORLD-LEADING R&D and METALLURGICAL

KNOW-HOW.

• Extensive KNOWLEDGE about

CUSTOMER APPLICATIONS.

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• SERVICE OFFERING in materials technology.

• DRIVING THE MATERIALS EVOLUTION,

contributing to making industrial activity SAFER,

MORE EFFICIENT and SUSTAINABLE.

Furnaceproductsandheatingsystems

Tube, pipe,fittings andflanges

Bar and hollow bar

Welding products

Strip steel andstrip-basedproducts

Wire

Hot isostaticpressed (HIP)products

Metal powder

Controlledexpansion (CEalloy products

Billets and blooms

PRODUCT OFFERING IN ADVANCED MATERIALS

6

Research questions

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Research areas of interest

Corrosion

• Composition of the passive film (1-5nm) in Ni-

based alloys

• Mechanisms for pitting and stress corrosion in

chloride solutions

• Mechanisms for hydrogen embrittlement in H2S

environments including the impact of chlorine and

sour environments, and pressure

• Growth of the oxide film as a function of alloy

composition at high temperatures

• Oxidation of ferritic stainless steels in chlorine

environments at high temperatures

• Metal dusting

Welding

• Microstructural development in the HAZ

• Improved understanding of sub-solidus

intergranular cracking (ductility dip cracking)

• Cooling down processes including residual stress,

appearance of welding defects (e.g. hot cracks

and inclusions)

• Development of brittle phases in welding of

alumina forming steels

• Corrosion mechanisms in weld deposit and the

HAZ

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CORROSION

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Pitting corrosion in 316 stainless steel

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Influence of MnS inclusions

M. P. Ryan et al Nature 14, 770 (2002)

Traditional view

Including influence

thermodynamic

treatment

Metal dusting

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P. Szakalos thesis, KTH 2004

Initiation in the center of

large grains Material model Open questions

• Critical thickness for

protective chromia film?

• Chemical composition of

the film as a function of

gas pressure?

• Speed and driving force

for the lather diffusion?

WELDING

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HAZ in duplex stainless steel

13

Microstructure and temperature welded SAF 2507

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Distance from FZ

M. S. F. de Lima, S. M. de Carvalho, V. Teleginskia, M. Pariona, Mat. Res. 18, 723 (2015).

Desiderata

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Absorption experiments, local

geometry16

Inelastic vs. elastic scattering

17

I I e tI

It o

t o

t

, ln ,

t

Io It

= absorption

coefficient (m-1)

= density (kgm-3)

= mass absorption

cross section (m2/kg)

I0 = incident

photon flux

t = thickness

It = transmitted flux

Inelastic vs. elastic scattering

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Some

mathematics,

correction to

phase angel

and so on..

Fourier

transform

In situ XAS measurement

19 S. Y. Lai, D. Ding, M. Liu, M. Liu, and F. M. Alamgir ChemSusChem, 7, 3078 (2014).

Tomography

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In situ synchrotron tomographic investigation of the

solidification of an AlMg4.7Si8 alloy

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Mg2Si particles

segmented from

microtomography at

the onset of their

growth at 575 °C.

D. Tolnai, P. Townsend, G. Requena, L. Salvo, J. Lendvai, and H.P. Degischer, Acta Mater.

60, 2568 (2012).

In situ synchrotron tomographic investigation of the

solidification of an AlMg4.7Si8 alloy

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Growth of the α-Al

dendrites at

different

temperatures

during cooling. The

voxel size is

(1.4 μm)3. The

different colours

correspond to

different α-Al

dendrites

D. Tolnai, P. Townsend, G. Requena, L. Salvo, J. Lendvai, and

H.P. Degischer, Acta Mater. 60, 2568 (2012).

Processes that could be investigated with in situ

tomography

• Welding metallurgy

• Sintering processes

• Solidification mechanisms

• Grain growth?

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Diffraction

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High penetration depth: e.g Swedish beamline at

PETRA, impact of high energy (40-150 keV)

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In situ experiments: Synchrotron-based experiments

for weld investigations

26

John W. Elmer, 2015 Workshop on Collection and Analysis of Big Data in 3D

Materials Science, UCSB, Santa Barbara, CA, USA.

In situ Gleeble and dilatometer measurements

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Thank you for the attention

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