Hydrogen Embrittlement of Steel

Gaël GUETARD 1Gaël GUETARD

English presentation - 16/02/12Tutor : David DELAFOSSE

Summary

2

What is the « hydrogen embrittlement » ?

How does it work ? What are the risks ?

Why is it a topical issue?

What is hydrogen used for? What will it be used for?

How to study the « hydrogen embrittlement » ?

What is the experimental setup ?What do we measure?

3

Fe (140pm)

H (25 pm)

C (70 pm)

Comparison of radii

Why is the hydrogen corrosion so special ?

Hydrogen diffusion (1)

Mobility in α-iron at 20°C :

1 mm/min

4

Hydrogen diffusion (2)

FLUID METAL AIR

H H H H H H

diffusion

adsorption

absorption desorptio

n

sorption

Perfect Crystals

5

V

vacancies

dislocations

grain boundaries

precipitates

cavities

interphases

Hydrogen trapping (1)

6

Hydrogen trapping (2)

Hydrogen in grain boundaries an in the

pearlitic phase

Hydrogen on a manganese sulfide in a ferritic steel

Sources: Ohmisawa 2003 / Otsuka 2007

7

Hydrogen embrittlement

H

HH

H

HH

H2 H2H2

a loss in ductility a loss load carrying ability cracking (usually as sub-microscopic

cracks) catastrophic brittle failures

Recombination in H2

It can cause :

World production :

50 million

metric ton per yearFertilizer

Hydrocracking

8

Increasing demand of hydrogen for actual uses

Why do we need to improve steel resistance to hydrogen embrittlement ?

pro

babili

ty

10 % growth each year

9

Increasing demand of hydrogen for actual uses

Why do we need to improve steel resistance to hydrogen embrittlement ?

Oil extraction in harsher conditions

pro

babili

ty

Less accessible ressources

+An increasing

demand=

Harsher extraction conditions

High hydrogen sulfid concentration

10

Increasing demand of hydrogen for actual uses

Why do we need to improve steel resistance to hydrogen embrittlement ?

Oil extraction in harsher conditions

Storage and transport of renewable energiesp

robabili

ty

Discontinous energy production

Hydrogen can be a good way to store and

transport it

11

Increasing demand of hydrogen for actual uses

Why do we need to improve steel resistance to hydrogen embrittlement ?

Oil extraction in harsher conditions

Development of the “Hydrogen Economy”

Storage and transport of renewable energiesp

robabili

ty

Alternative economy based on hydrogen instead of oil

12

Increasing demand of hydrogen for actual uses

Why do we need to improve steel resistance to hydrogen embrittlement ?

Oil extraction in harsher conditions

Development of the “Hydrogen Economy”

Storage and transport of renewable energiesp

robabili

ty • More resistant steel (for a given price)

• Cheaper steel (for a given resistance)

• Steel that requires less maintenance

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Example

What is the price for a 1%wt decrease of Nickel in a pipeline ?

P=20$/kg

PriceLengthSection Density

D=1me=2cm

L=10km ρ=8kg/L

=$ 2,000,000

x x x

14

My Research Project

Traction and Permeation tests

Sources: Moro 2007

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My Research Project

Better understanding of the embrittlement mecanisms:

Trapping Mechanical properties

TrappingMicrostructure

Thanks for your attention

Questions ?

16