Influence of shielding gases on grain refinement in welds of stabilized 21 % Cr ferritic stainless steel

2014 ◽  
Vol 58 (6) ◽  
pp. 805-817 ◽  
Author(s):  
S. Anttila ◽  
D. A. Porter

2021 ◽  
Vol 194 ◽  
pp. 113690
Author(s):  
A. Durga ◽  
Niklas Holländer Pettersson ◽  
Sri Bala Aditya Malladi ◽  
Zhuoer Chen ◽  
Sheng Guo ◽  
...  


2015 ◽  
Vol 4 (2) ◽  
pp. 13-13
Author(s):  
M.O.H. Amuda ◽  
E.T. Akinlabi ◽  
S. Mridha


2012 ◽  
Vol 445 ◽  
pp. 717-722 ◽  
Author(s):  
M.O.H. Amuda ◽  
S. Mridha

Grain refinement in medium chromium ferritic stainless steel weld was attempted via elemental (aluminum) powder pre-placement technique prior to melting under a TIG torch. A Box-Behnken experimental design was adopted with current, travel speed and the amount of aluminum powder added as the process factors for producing weld pool. The resolidified weld tracks were characterized using microscopy, microhardness and mechanical testing. The degree of grain refinement achieved was evaluated using a scaling index known as Grain Refinement Index (GRI). The findings showed that the GRI is influenced by the concentration of the aluminum powder introduced into the melt pool. Furthermore, high GRI does not necessarily translate to better mechanical properties relative to the conventional weld. This suggests that the grain size effect might not be the only factor influencing the property of weld metal. However, weld track treated with 0.08mg/mm2 of aluminum powder exhibited about 20% improvement in properties relative to the conventional weld made under the same energy conditions.



2009 ◽  
Vol 83-86 ◽  
pp. 1165-1172 ◽  
Author(s):  
M.O.H. Amuda ◽  
S. Mridha

The ferritic stainless steel is a low cost alternative to the most often adopted austenitic stainless steel due to its higher strength, better ductility and superior corrosion resistance in caustic and chloride environments. However, the application of ferritic steel is limited because of poor ductility and notch impact toughness of its weld section with differential grain structures. Several techniques have been explored to control the grain features of the weld to minimize these problems. In the present effort, a review of these options in relation to the degree of grain refinement in ferritic stainless steel weld is conducted in order to have a better understanding about the grain refining phenomenon in the weld microstructure. So far, the most effective technique is found to be the pulse AC TIG welding which can produce weld with mechanical properties equivalent to 65% to those of the base metal. The refinement in this process occurred through dendrite fragmentation and grain detachment in the weld pool producing small-grained microstructures with a large fraction of equiaxed grains. However, in friction welding process where heat input and heat transfer are effectively controlled, the strength can be as high as 95% of the parent metal. This suggests that the total energy input for welding and heat transfer phenomenon mainly control the development of microstructural feature in the weld pool and hence the strength.





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