Fatigue behavior of plain C–Mn steel plates with fine grained ferrite in surface layers

The Effect of Cyclic Solution Heat Treatment on the Martensitic Phase Transformation and Grain Refinement of Co-Cr-Mo Dental Alloy

“…According to the classical Hall-Petch relationship (for grain sizes larger than 1 µm), the yield strength increases as grain size decreases which is attributed to the grain boundaries acting as obstacles to slip dislocations causing dislocation pile-up behind grain boundaries. Therefore, surface modification through grain refinement of the surface layer could effectively enhance the surface proportioned properties such as wear resistance (surface hardness) and fatigue performance [6,7]. Generally, in Co-based alloys, ε phase with hexagonal close-packed (hcp) structure, are expected to be stable at room temperature, but γ phase with a face-centered-cubic (fcc) structure is a typical and quite common structure at room temperature.…”

Mechanical properties and microstructure of longitudinal submerged arc welded joint of a new C–Mn steel sheet cladding fine grained ferrite in surface layer for a long distance transport pipeline

“…The microstructure of the LSAW joint is mainly made up of the coarse martensite phase and the bainite phase. These researches show that the size of prior austenite grain, the volume fraction of bainitic ferrite, and M/A constituent increase with increasing the cooling time, moreover the martensite's volume fraction decreases [14][15][16][17][18]. Remarkable of toughness decrease observes with increasing the size of austenite grain and the volume fraction of M/A constituent.…”

“…This kind of metal-filled zone's phases is characterized by a brittle microstructure that greatly hinders the mechanical properties of the welded joint. The ferrite phase generally exhibits a lower strength than that of the bainite and martensite phases [16][17][18][19][20]. As the Hall-Petch relationship suggests, a reduction in grain size will improve mechanical properties, including hardness and yield stress.…”

“…Since the end of the twentieth century, many materials research projects have focused on ultra-fine grain (UFG) steel. Some research results of the laboratory have applied in the metallurgical industry [14][15][16][17][18]. The smallest ferrite grain size approaches 5.5 μm in the surface layers, and can reaches 6.5 μm on average in the whole thickness of the plates.…”

“…The LSAW is one of basic welding technology for the pipeline duo to its low cost, high efficiency, and good applicability [1]. However, because the characteristics of the LSAW, the properties of the metal-filled zone and the heat-affected zone are more difficult to control than that of the base metal, so the welding seam or welding joint is a weak for manufacturing the pipeline [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”