Page 42 - SSAB Welding Handbook Edition 2

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6.0 The choice of consumables Welding handbook

6.7 Stainless austenitic consumables Hardfacing Buffer layer
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Welding the Hardox and Strenx grades with
stainless austenitic consumables offers certain
features. A main reason being that the weld metal in
the joint will include a substantial amount of
austenite in the microstructure after welding. Steel substrate
Fig. 6.3: Appliance of a buffer at hardfacing layer on a
A joint that is welded with an appropriate stainless Hardox/Strenx plate
consumable has a very high resistance towards
hydrogen cracks. This is because the austenite in
the weld metal dissolves hydrogen more than the Essential drawbacks with stainless consumables
microstructures in unalloyed and low-alloyed are that:
consumables. This largely counteracts the negative 4 Low-alloyed consumables are feasible in higher
effects of hydrogen in the joint. strengths compared to stainless austenitic
consumables. The yield strengths of suitable
Additionally, the austenite in the weld metal consumables are up to approximately 500 MPa
supports ductility. This typically means that the in the all weld metal.
impact toughness in the weld metal of the joints 4 Flame cutting in joints welded with stainless
exceeds the requirements for the individual austenitic consumables is not possible. However,
Hardox and Strenx grade. all other thermal cutting techniques can be
applied in these weldments.
Other important benefits of welding with stainless
austenitic consumables are that: 4 Stainless austenitic consumables are more
4 Preheat temperatures, which means a temperature expensive than unalloyed and low-alloyed
above +20°C in the joint as well as in the consumables.
surrounding air, can be avoided prior to welding
for all Hardox and Strenx steels, except for The recommended stainless consumable is of type
Hardox 600 and Hardox Extreme. The two AWS 307. A second alternative is a consumable of
latter steel grades require preheating, according type AWS 309, which is often used when an
to chapter 4. AWS 307 is not commercially available. However,
the risk of hot cracking in the weld metal is somewhat
4 Stainless austenitic consumables are suitable for higher for AWS 309 in relation to AWS 307.
welding the Hardox and Strenx grades to other
kinds of steels, such as: The hydrogen potential of stainless consumables
- Stainless steels is of secondary importance due to their high
- Manganese steels (Hadfield steels), which resistance to hydrogen cracks. According to
have a Mn content of approximately 13% evaluations performed by SSAB, there are no
- Steels that are difficult to weld, such as formal restrictions regarding maximum hydrogen
spring steels content for these types of consumables. However,
4 It is preferred that the buffer layer at the consumables are to be handled according to
hardfacing is welded with stainless consumables, their manufacturer in order to avoid unnecessary
according to fig. 6.3. Further information on this hydrogen pick-up.
matter is found in chapter 20.

42 This handbook contains general suggestions and information without any expressed or implied warranty of any kind. SSAB hereby expressly disclaims
all liability of any kind, including any damages, in connection with the use of the information and for their suitability for individual applications.
It is the responsibility of the user of this brochure to adapt the recommendations contained therein to the requirements of individual applications.