Metallographic inspection of flat-rolled semifinished products

1998 ◽  
Vol 41 (12) ◽  
pp. 1136-1138
Author(s):  
O. K. Kolerov ◽  
A. N. Logvinov
Keyword(s):  
Metallographic Inspection

An EBSD Study on Orientation Effects during Recrystallization of Coarse-Grained Niobium

2004 ◽  
Vol 467-470 ◽  
pp. 519-524 ◽  
Author(s):  
Hugo Ricardo Zschommler Sandim ◽  
Dierk Raabe
Keyword(s):  
Longitudinal Section ◽  
Primary Recrystallization ◽  
Coarse Grained ◽  
Subgrain Structure ◽  
Electron Backscattered Diffraction ◽  
Subgrain Growth ◽  
Metallographic Inspection ◽  
Cold Rolled ◽  
Cold Worked ◽  
Viable Mechanism

The recrystallization behavior of coarse-grained niobium depends on the nature of its deformation microstructure. In this regard, a longitudinal section of a high-purity coarse-grained niobium ingot was cold rolled to a thickness reduction of 96% followed by annealing in vacuum at 800°C for 1 h. Metallographic inspection in cold-rolled and annealed specimens was carried out in a field emission gun scanning electron microscope (FEG-SEM). Microtexture was determined by electron-backscattered diffraction (EBSD) coupled to the FEG-SEM. The use this technique has evidenced details of the boundary character and subgrain structure found in partially recrystallized regions. The early stages of primary recrystallization are associated to the presence of high-angle lamellar boundaries found in the cold-worked state. Abnormal subgrain growth has been evidenced as a viable mechanism for nucleation of recrystallization.

Metallographic inspection of the metal-enamel contact zone

1983 ◽  
Vol 25 (6) ◽  
pp. 472-475 ◽  
Author(s):  
Yu. A. Dudnik
Keyword(s):  
Contact Zone ◽  
Metallographic Inspection

Discussion of Wetting Phenomena Under Reducing Atmospheres Using a High Resolution Wetting Balancem

1986 ◽  
Vol 72 ◽  
Author(s):  
B. Jahnke ◽  
H. Reiss
Keyword(s):  
High Resolution ◽  
Interfacial Energies ◽  
Wetting Phenomena ◽  
Adsorption Processes ◽  
Metallographic Inspection ◽  
Diffusion Precipitation

AbstractIn wetting phenomena surface and interfacial energies play an important part. Due to diffusion, precipitation and adsorption processes these energies are time and temperature dependently changing. The influence on wetting behaviour is investigated using a high resolution wetting balance and metallographic inspection.

Metallographic Investigation on Solder Creep Phenomenon

2012 ◽  
Author(s):  
Paul Angelo D. Gustilo ◽  
Joyce Lyn G. Fernandez
Keyword(s):  
Deformation Mechanism ◽  
Visual Inspection ◽  
Grain Shape ◽  
Process Conditions ◽  
Ishikawa Diagram ◽  
Metallographic Investigation ◽  
Material Deformation ◽  
Metallographic Inspection ◽  
Free Area ◽  
Actual Unit

Abstract Solder bulging is detected on the exposed paddle of Device A after burn-in causing the affected units to fail the coplanarity criteria. The affected units show up at random burn-in board socket locations and occur with varying frequency. Potential causes are plotted through an Ishikawa diagram which reveal fusion and creep as the potential mechanisms behind the solder bulging phenomenon. This paper seeks to determine the mechanism behind the solder bulging phenomenon via a 2-step metallographic investigation through (i) material deformation characterization and (ii) deformation mechanism simulation. In material deformation characterization, visual inspection on affected units show that the solder bulge is generally circular and is located on the center of the exposed paddle. Moreover, SEM/EDX analysis reveal that the solder bulge is not caused by a foreign contaminant or a compositional anomaly in the solder plating. On the other hand, deformation mechanism simulation involves the metallographic comparison between controlled simulations of fusion and creep versus the actual unit with solder bulge. Metallographic inspection reveal that the grain size and grain shape of the solder bulge possess the characteristics of creep phenomenon. Additionally, investigation on the burn-in (BI) process conditions also supports creep over fusion as the mechanism behind the solder bulging phenomenon. The static stress induced by the socket on the package at elevated temperature caused the solder plating to creep towards the free area which is the hole on the bottom of the socket.

Leakage Failure Analysis of the ERW Steel Pipeline

2020 ◽  
Vol 993 ◽  
pp. 1224-1229
Author(s):  
Shen Cong ◽  
Ke Tong ◽  
Dong Feng Li ◽  
Zhi Xin Chen ◽  
Ke Cai
Keyword(s):  
Small Volume ◽  
Oil Field ◽  
Residual Liquid ◽  
Steel Pipeline ◽  
Corrosion Medium ◽  
Hot Air ◽  
Pressure Test ◽  
Metallographic Inspection ◽  
Leakage Failure ◽  
Scanning Electron

This paper provides a thorough investigation on the leakage reason of the ERW steel pipeline in an oil field. Through appearance inspection, physicochemical inspection, metallographic inspection and scanning electron microscope (SEM), it was found that the main reason of corrosions was caused by residual liquid at the bottom of the pipeline and O2 and CO2 in the air pressure test. The corrosion medium was large volume of O2 and CO2 forming continuously saturated corrosive aqueous solution in small volume of residual liquid, and the corrosion type was the under-deposit corrosion. It is recommended to conduct hot air purging on the pipelined before pressure test for building pipelines in the future, and if the pipeline is not put into use in time, it is recommended to use nitrogen to maintain pressure.

Shrinkage Pores and Fatigue Behavior of Cast Al-Si Alloys

2011 ◽  
Vol 465 ◽  
pp. 354-357 ◽  
Author(s):  
Radomila Konečná ◽  
S. Fintová ◽  
Gianni Nicoletto
Keyword(s):  
Room Temperature ◽  
Fatigue Testing ◽  
Critical Size ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Casting Defect ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Metallographic Inspection ◽  
Rotating Bending

The fatigue strength of cast Al-Si alloys is strongly sensitive to the presence of casting defects. Extensive rotating bending fatigue testing of cast AlSi7Mg alloy at room temperature and 50 Hz is reported showing that shrinkage pores are the critical casting defect. The porosity of selected fatigue specimens extracted from castings is characterized with metallography using different pore sizing criteria. Data are fitted to EVS distributions and used for critical size prediction. Fatigue fracture surfaces are inspected in the SEM and the critical pores originating the fatigue cracks identified and measured according to criteria used in the metallographic inspection.

Studies on the metallographic inspection of HK‐40 reformer tubes

1984 ◽  
Vol 31 (3) ◽  
pp. 9-15
Author(s):  
K.M. Verma ◽  
S.C. Verma ◽  
A.K. Sinha
Keyword(s):  
Metallographic Inspection ◽  
Reformer Tubes

Repair of Aluminum 6061 Plate by Additive Friction Stir Deposition

2021 ◽  
Author(s):  
Louis Peter Martin ◽  
Allen Luccitti ◽  
Mark Walluk
Keyword(s):  
Solid State ◽  
Aluminum Alloys ◽  
Heat Affected Zone ◽  
High Performance ◽  
Fatigue Testing ◽  
Void Formation ◽  
Process Conditions ◽  
Friction Stir ◽  
Common Strategy ◽  
Metallographic Inspection

Abstract The deposition of new alloy to replace a worn or damaged surface layer is a common strategy for repairing or remanufacturing structural components. For high-performance aluminum alloys common in the automotive, aerospace, and defense industries, however, traditional fusion-based deposition methods can lead to solidification cracking, void formation, and loss of strength in the heat affected zone. Solid state methods, such as additive friction stir deposition (AFSD), mitigate these challenges by depositing material at temperatures below the melting point. In this work, a solid state volumetric repair was performed using AFSD of aluminum alloy 6061-T6 to fill grooves machined into the surface of a plate of 6061-T651. The groove-filling process is relevant to replacement of cracked or corroded material after removal by localized grinding. Three groove geometries were evaluated by means of metallographic inspection, tensile testing, and fatigue testing. For the process conditions and groove geometries used in this study, effective repairs were achieved to a depth of 3.1 – 3.5 mm. Below that depth, the interface between the substrate and AFSD filler exhibited poor bonding associated with insufficient shear deformation. The mechanical properties of the filler alloy, the depth of the heat affected zone, and areas for further optimization are discussed within the context of precipitation hardened aluminum alloys.

Failure Analysis of a Diesel Engine Crankshaft

2021 ◽  
Vol 58 (5) ◽  
pp. 282-298
Author(s):  
H. Y. Zhang ◽  
S. Qu ◽  
C. Dong ◽  
C. M. Fu ◽  
Q. S. Zang ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Diesel Engine ◽  
Crack Initiation ◽  
Stress Condition ◽  
Fatigue Crack Initiation ◽  
Complex Stress ◽  
Bench Test ◽  
Root Cause ◽  
Metallographic Inspection ◽  
Engine Crankshaft

Abstract A six-cylinder crankshaft in a 12L diesel engine was locked after testing for about 840 hours in the bench test. The fractography investigation indicates that fatigue is the dominant failure mechanism of the crankshaft. It is found that the fatigue crack mainly initiated at the fillet of the crankweb between the 6th main journal and 6th crankpin. The fatigue crack initiation area lies outside the induction surface hardened zone. From detailed metallographic inspection, abnormal microstructure containing Widmannstatten was found in the fatigue crack initiation area and the 5th main journal, while that was not found at the severely deformed crankweb. Since the region containing Widmannstatten has lower hardness, the root cause of the failure may be that the abnormal microstructure lowered the fatigue strength at the stress concentrated fillet. The crankshaft prematurely fractured under the complex stress condition in the bench test.

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