Microstructure and Mechanical Properties of Silicon Carbide-Treated Ferritic Stainless Steel Welds

2021 ◽  
pp. 395-411
Author(s):  
Muhammed O. H. Amuda ◽  
Taiwo Folorunsho Lawal ◽  
Shahjahan Mridha
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Grain Morphology ◽  
Grain Structure ◽  
Weld Geometry ◽  
Powder Addition ◽  
Steel Welds ◽  
Equiaxed Grain

To further previous works on grain refinement in ferritic stainless steel (FSS) welds via elemental powder addition, microstructure evolution and mechanical properties in non-metallic carbide treated FSS weld is discussed. Silicon carbide (SiC) powder preplaced on medium chromium FSS bevelled joint was fusion melted using tungsten inert gas (TIG) torch at different combination of process parameters. The incorporation of the powder in the weld pool constricted the weld geometry in addition to grain modification from columnar to equiaxed grain structure. Whilst significant improvement was obtained in hardness characteristics in powder treated welds, those of ductility and tensile strength were marginal. The study also established that welds mechanical properties are controlled by a combination of phenomena such as phase fraction and grain morphology.

Grain Refinement in Medium Chromium Ferritic Stainless Steel Welds via Aluminum Powder Addition

2012 ◽  
Vol 445 ◽  
pp. 717-722 ◽  
Author(s):  
M.O.H. Amuda ◽  
S. Mridha
Keyword(s):  
Stainless Steel ◽  
Grain Refinement ◽  
Ferritic Stainless Steel ◽  
Aluminum Powder ◽  
Travel Speed ◽  
Energy Conditions ◽  
Melt Pool ◽  
Powder Addition ◽  
Process Factors ◽  
Steel Welds

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.

scholarly journals Microstructure and mechanical properties of AISI 439 ferritic stainless steel welds without filler metal

2019 ◽  
Vol 29 ◽  
pp. 1-12
Author(s):  
Juan Manuel Salgado López ◽  
Marc Preud homme ◽  
Francisco Lopez Monroy ◽  
Jose Luis Ojeda Elizarráraz ◽  
Arturo Toscano Giles
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Tensile Test ◽  
Grain Growth ◽  
Ferritic Stainless Steel ◽  
Filler Metal ◽  
Testing Machine ◽  
Thin Plates ◽  
Technical Literature ◽  
Steel Welds

In literature, it has been reported that a current intensity lower than 120 A leads to a microstructure without grain growth in the heat affected zone (HAZ) of ferritic stainless steel welds. Nevertheless, in technical literature there is little information about the reduction in mechanical properties of ferritic stainless steel welds without filler metal due to grain growth in the HAZ. In this work, thin plates of ferritic stainless 439 steel were welded using pulse current gas tungsten arc welding (P-GTAW) without filler metal. The microstructures in the HAZ were analyzed and the mechanical properties on the welded joint were found by tensile test. This was carried out by cutting samples for the tensile test from the weldments and then tested in a universal testing machine. The fracture surface were observed using scanning electron microscope.

Influences of Grain Refining Conditions on Sensitization in 16 wt% Chromium Ferritic Stainless Steel Welds

2012 ◽  
Vol 576 ◽  
pp. 496-499
Author(s):  
M.O.H. Amuda ◽  
S. Mridha
Keyword(s):  
Stainless Steel ◽  
Oxalic Acid ◽  
Ferritic Stainless Steel ◽  
Cryogenic Cooling ◽  
Inert Gas ◽  
Grain Refining ◽  
Powder Addition ◽  
Titanium Powders ◽  
Steel Welds ◽  
Metal Powder Addition

The paper discusses sensitization characteristics in medium chromium Ferritic Stainless Steel (FSS) welds processed at two different grain refining conditions namely metal powder addition and cryogenic cooling. Tungsten Inert Gas (TIG) torch welded samples were exposed to 10% oxalic acid electrolytic etch for evaluation of sensitization. Empirical analysis indicated that, though both the grain refining conditions reduced the sensitization width relative to the conventional weld, the width was virtually nil with cryogenic cooling suggesting the elimination or reduction of sensitization. Similarly, the microstructure of cryogenically cooled welds showed no ditched grain boundary but aluminum powder treated welds revealed extensive ditching and none in titanium treated welds while knifeline attack was observed in welds treated with the mixture of aluminum and titanium powders.

Influence of Nb-Ti Composition on Recrystallization of Ferritic Stainless Steel

2011 ◽  
Vol 702-703 ◽  
pp. 619-622
Author(s):  
Yi Qiao Yang ◽  
Yan Dong Liu
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Recrystallization Texture ◽  
Texture Evolution ◽  
Grain Morphology ◽  
Continuous Annealing ◽  
Recrystallization Process ◽  
Additional Amount ◽  
Equiaxed Grain

An experimental study of the microstructural and texture evolution attending recrystallization of Nb-Ti stabilized ferritic stainless steel is presented. Two specimens with different Nb-Ti compositions, TCS345 and B4003, have been selected for comparison. The result shows that, after annealing at 750 °C for 5min, the major orientation in the TCS345 specimen locates at {111}, microstructures presents an equiaxed grain morphology, whereas the texture in the B4003 is not typical recrystallization texture and remains weak, indicating recrystallization occur preferentially to the TCS345 sheet. And after continuous annealing at 850°C for 5 min, the texture in TCS345 remains stronger than in the B4003, indicating that the additional amount of Nb-Ti acts to significantly hinder the recrystallization process.

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