Achieving excellent mechanical properties in type 316 stainless steel by tailoring grain size in homogeneously recovered or recrystallized nanostructures

The objective of this study is to investigate and determine the effect of the stand-off distance (distance between the welded plates) on the mechanical properties of the Tungsten Inert Gas (TIG) welded joints. Butt TIG welding was performed for 316 stainless steel (SS) by using different pre welding stand-off distances with fixing the other parameters (thickness of welded plates, voltage, current, groove shape, and scanning speed). The influence of the stand-off distance parameter was examined by using tensile test, hardness test in the three different regions (base metal, heat effected zone, and molten zone), non-destructive testing (including visual inspection, liquid pentrant and X – ray) and microscopic examinations. Results show that the stand-off distance is one of the most important geometrical parameters of the Butt welded joints to end by good mechanical properties. It is found that the optimum stand-off distance was about 1 mm (shows the highest hardness results), but still there were some defects in some spots in the molten metal zone which caused a decrease in the hardness values in these locations. The 2 mm stand-off distance shows reasonable results, and the worst case was recorded for the 0 mm stand-off distance condition. Generally the hardness values of the heat affected zone in all conditions were the highest when compared to both metal welding zone and the base metal zone.

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Effect of alloy grain size on oxidation resistance of silica-coated stainless steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171110 ◽

1994 ◽

Vol 52 ◽

pp. 676-677

Author(s):

C. S. McDowell ◽

S. N. Basu

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Stainless Steel ◽

Oxidation Resistance ◽

Powder Processing ◽

Hot Isostatic Pressing ◽

Silica Coating ◽

Austenitic Steels ◽

Coarse Grained ◽

Fine Grained

Oxidation resistance of stainless steels, which rely on the formation of a Cr2O3 (chromia) scale, can be further improved through minor alloying additions such as Al or Si, or by application of coatings to the exposed surfaces. Although, additions of Si to austenitic steels have demonstrated an improvement in oxidation resistance, high Si contents can be detrimental to the mechanical properties of these alloys. The application of a silica coating on the surface of the stainless steel provides improved oxidation resistance without detrimental effects on the mechanical properties. This study examines the effect of the grain size of the stainless steel on the effectiveness of a silica coating as an oxidation barrier.Fully austenitic stainless steel of composition Fe-18(wt%)Cr-20Ni-1.5Mn was produced in both coarsegrained and fine-grained form. The coarse-grained alloy, with a grain size of approximately 100 μm, was produced by casting and hot rolling. The fine-grained alloy, with a grain size of approximately 5 μm, was produced by rapid solidification powder processing, followed by consolidated by hot isostatic pressing and swaging.

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