Mechanical Properties and Microstructures of Narrow Gap Orbital Welded P91 Steel

2016 ◽  
Vol 258 ◽  
pp. 635-638 ◽  
Author(s):  
Michal Junek ◽  
Marie Svobodová ◽  
Jiří Janovec ◽  
Jakub Horváth
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Room Temperature ◽  
Tensile Specimen ◽  
Narrow Gap ◽  
P91 Steel ◽  
Microstructure Evaluation ◽  
The Individual

This article deals with the results of mechanical testing and structural analysis of sections of narrow gap orbital welded P91 steel on tube OD 355.6 x 40 mm. The evaluation of mechanical properties was based on tensile test at room temperature on mini-tensile specimens and on measurement of modulus of elasticity. Weld was cut longitudinally into 9 narrow slices by using waterjet. From these slices 108 flat mini-tensile specimens (dimensions of gauge is 2 x 2 mm) were prepared. In experimental part microstructure evaluation and documentation of fracture surface of each mini-tensile specimen were carried out. The aim of these experiments was to assess the mechanical properties of the individual sections of the weld (base metal, heat affected zone and weld metal). These data can be used for new approaches of FEM modelling of welds considering heat affected zone like a combination of different materials with different mechanical properties, which connect the thermally unaffected base metal and weld metal.

scholarly journals Welding Soundness of a Thick-Walled 9Cr-1Mo Steel

2010 ◽  
Vol 654-656 ◽  
pp. 408-411
Author(s):  
Woo Seog Ryu ◽  
Sung Ho Kim ◽  
Dae Whan Kim
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Base Metal ◽  
Hardness Test ◽  
Ultimate Tensile Stress ◽  
Narrow Gap ◽  
Martensitic Steels ◽  
Narrow Gap Welding ◽  
Self Energy ◽  
Welding Processes

High Cr ferritic/martensitic steels are demanded to join using favorable welding processes with economical and metallurgical advantages in order to apply to the thick-walled reactor pressure vessel of a very high temperature gas cooled reactor. Narrow gap welding technology was adopted to weld a thick-walled 9Cr-1Mo-1W steel with thickness of 110mm. The welding integrity was checked by non-destructive examination, optical microscopy and hardness test, and the homogeneity through welding depth was checked by absorbed impact energy and tensile strength. The optimizing welding conditions resulted that a narrow U-grooved gap with almost parallel edges was sound in actual practice, and the coarse grain zone was minimized in the heat affected zone. The absorbed energy of 75±25 J through welding depth was acceptable in scatter band to check the uniformity through the welding depth. The ultimate tensile stress and yield stress were about the same through welding depth at 650±10 MPa and 500±10 MPa, indicating no difference through welding depth. Elongation was also almost same through depth, and the fracture surface was appeared as a normal. The weld metal had similar mechanical properties to base metal. The upper self energy of weld metal was 194J, and the ductile-brittle transition temperature was 30°C. The tensile behavior was the typical trend with temperature, and YS and UTS of weldment were slightly higher than base metal by nearly below 10%. Thus, it concluded that the soundness of the narrow gap welding of a thick-walled 9Cr-1Mo-1W steel was confirmed in terms of the welding uniformity through the depth and mechanical properties.

Mechanical Properties of Shielded Metal Arc Welded Low Carbon Steel: Effect of Butt Joint Type and Uncapping of Excess Weldment

2015 ◽  
Vol 1125 ◽  
pp. 195-199
Author(s):  
Toto Triantoro Budi Wardoyo ◽  
S. Izman ◽  
Safian Sharif ◽  
Hosta Ardhyananta ◽  
Denni Kurniawan
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Carbon Steel ◽  
Weld Metal ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Low Carbon Steel ◽  
Butt Joint ◽  
Low Carbon ◽  
Shielded Metal Arc Welding

In this paper, Shielded Metal Arc Welding (SMAW) was performed on low carbon steel with three types of butt joint (i.e., square, single V, and double V) and uncapping of the weldment. The welding performance is measured based on the mechanical properties (i.e., strength and hardness). Grain size and microstructure of the weldments were also evaluated. The results show that all tested samples show similar tensile strength, which means there was no significant effect of the type of butt joint type or uncapping. The hardness of the weld metal was found to be slightly higher than that of heat affected zone and base metal, in which both showed similar hardness values. The grain size of the weld metal was also finer than that of heat affected zone and base metal. This trend in hardness and grain size on three regions of the welded sample was the same regardless of the butt joint type and whether the weldment was uncapped or not.

Weldment Evaluation of High Pressure Steam Rotors

1994 ◽  
Vol 116 (4) ◽  
pp. 429-434 ◽  
Author(s):  
D. Wojnowski ◽  
H. Kasapbasioglu ◽  
J. E. Indacochea ◽  
G. W. Galanes ◽  
T. D. Spry
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Weld Metal ◽  
Tensile Properties ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Elevated Temperatures ◽  
Rupture Strength ◽  
Stress Rupture ◽  
Life Extension

Life extension of high pressure and intermediate pressure rotors by weld repair is a viable alternative considering the latest developments. Our objective is to select a filler wire that will produce a weld with mechanical properties compatible with those of the rotor material. Three filler metals, (CrMoV, 12 percent Cr and 5 percent Cr) were used in the investigation. Multipass submerged arc groove welds were produced, post weld heat treated at 677° C (1250°F), and submitted to a series of mechanical tests at room and elevated temperatures. The tests samples were machined parallel to the weld direction (longitudinal), which included only weld metal, and perpendicular to the weld metal (crossweld) so that the test sample includes portions of the weld metal, heat-affected zone (HAZ) and base metal. A limited metallurgical evaluation was also performed. The room temperature tensile properties of the CrMoV and 12 percent Cr crossweld samples exceeded those of the rotor metal, but the tensile properties of the 5 percent Cr crosswelds did not match those of the rotor metal. The 12 percent Cr crossweld samples failed in the weld metal during hot tensile and stress rupture testing, and these failures were attributed to slag entrapment; yet the yield and tensile strengths of these weldments just exceeded those of the rotor base metal. The CrMoV crossweld specimens performed the best at the high temperature testing; the failure for the hot tensile specimens occurred in the weld metal and the values matched those of the all weld metal (longitudinal) specimens which greatly exceeded the rotor base metal strengths. The crossweld stress rupture samples failed outside the weld metal at the heat affected zone (HAZ) near the unaffected base metal with rupture lives lower than the rotor base metal. Microhardness evaluations in the CrMoV and 12 percent Cr cross weldments about the HAZ/base metal boundary identify a soft region at this location. The mechanical properties of the 5 percent weldment were in general inferior to the rotor base metal. The weld metal’s hardness was lower than the rotor base metal given its superior Charpy energy values; however, the creep rupture strength was inferior.

scholarly journals Analysis of the Microstructure and Mechanical Properties of TiBw/Ti-6Al-4V Ti Matrix Composite Joint Fabricated Using TiCuNiZr Amorphous Brazing Filler Metal

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 875
Author(s):  
Hao Tian ◽  
Jianchao He ◽  
Jinbao Hou ◽  
Yanlong Lv
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Matrix Composite ◽  
Room Temperature ◽  
Filler Metal ◽  
Ceramic Fiber ◽  
Tensile Fracture ◽  
Alloy Matrix ◽  
Composite Joint ◽  
Secondary Cracks

TiB crystal whiskers (TiBw) can be synthesized in situ in Ti alloy matrix through powder metallurgy for the preparation of a new type of ceramic fiber-reinforced Ti matrix composite (TMC) TiBw/Ti-6Al-4V. In the TiBw/Ti-6Al-4V TMC, the reinforced phase/matrix interface is clean and has superior comprehensive mechanical properties, but its machinability is degraded. Hence, the bonding of reliable materials is important. To further optimize the TiBw/Ti-6Al-4V brazing technology and determine the relationship between the microstructure and tensile property of the brazed joint, results demonstrate that the elements of brazing filler metal are under sufficient and uniform diffusion, the microstructure is the typical Widmanstätten structure, and fine granular compounds in β phase are observed. The average tensile strength of the brazing specimen is 998 MPa under room temperature, which is 97.3% of that of the base metal. During the high-temperature (400 °C) tensile process, a fracture occurred at the base metal of the highest tensile test specimen with strength reaching 689 MPa, and the tensile fracture involved a combination of intergranular and transgranular modes at both room temperature and 400 °C. The fracture surface has dimples, secondary cracks are generated by the fracture of TiB whiskers, and large holes form when whole TiB whiskers are removed. The proposed algorithm provides evidence for promoting the application of TiBw/Ti-6Al-4V TMCs in practical production.

scholarly journals Properties of a thick-section narrow-gap gas tungsten arc weld of cast Haynes 282

2021 ◽  
Author(s):  
Michael Santella ◽  
X. Frank Chen ◽  
Philip Maziasz ◽  
Jason Rausch ◽  
Jonathan Salkin
Keyword(s):  
Base Metal ◽  
Heat Affected Zone ◽  
Reference Data ◽  
Filler Metal ◽  
Stress Rupture ◽  
Narrow Gap ◽  
Weld Deposit ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Weld Heat

AbstractA 50.8-mm-deep gas tungsten arc weld was made with matching filler metal in cast Haynes 282 alloy. The narrow-gap joint was filled with 104 weld beads. Visual and dye-penetrant inspection of cross-weld specimens indicated that the cast base metal contained numerous casting defects. No visible indications of physical defects were found in the weld deposit. The weld heat-affected zone was characterized by microcracking and localized recrystallization. The cause of the cracking could not be determined. Hardness testing showed that a softened region in the as-welded heat-affected zone was nearly eliminated by post-weld heat treatment. Tensile testing up to 816 °C showed that cross-weld specimen strengths ranged from 57 to 79% of the cast base metal tensile strength. The stress-rupture strengths of cross-weld specimens are within 20% of base metal reference data. Failures of both tensile and stress-rupture specimens occurred in the base metal.

Gas metal arc welding of XPF800 steel for automotive industry: Microstructural evaluation and mechanical properties investigation

2021 ◽  
pp. 146442072110567
Author(s):  
Emre Korkmaz ◽  
Cemal Meran
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Automotive Industry ◽  
Heat Affected Zone ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Charpy Impact ◽  
Optical Microscope ◽  
Metal Arc Welding ◽  
Heat Affected Zone Softening

In this study, the effect of gas metal arc welding on the mechanical and microstructure properties of hot-rolled XPF800 steel newly produced by TATA Steel has been investigated. This steel finds its role in the automotive industry as chassis and seating applications. The microstructure transformation during gas metal arc welding has been analyzed using scanning electron microscope, optical microscope, and energy dispersive X-ray spectrometry. Tensile, Charpy impact, and microhardness tests have been implemented to determine the mechanical properties of welded samples. Acceptable welded joints have been obtained using heat input in the range of 0.28–0.46 kJ/mm. It has been found that the base metal hardness of the welded sample is 320 HV0.1. On account of the heat-affected zone softening, the intercritical heat-affected zone hardness values have diminished ∼20% compared to base metal.

Effect of Post Weld Heat Treatment on Fusion and Heat Affected Zone Microstructure and Mechanical Properties of Inconel X-750 Welds

2011 ◽  
Vol 214 ◽  
pp. 108-112 ◽  
Author(s):  
Prachya Peasura ◽  
Bovornchok Poopat
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Grain Boundary ◽  
Weld Metal ◽  
Heat Affected Zone ◽  
Aging Temperature ◽  
Post Weld Heat Treatment ◽  
High Aging Temperature ◽  
Zone Microstructure

The Inconel X-750 indicates good hot corrosion resistance, high stability and strength at high temperatures and for this reason the alloy is used in manufacturing of gas turbine hot components. The objective of this research was study the effect of post weld heat treatment (PWHT) on fusion zone and heat affected zone microstructure and mechanical properties of Inconel X-750 weld. After welding, samples were solutionized at 1500 0C. Various aging temperature and times were studied. The results show that aging temperature and time during PWHT can greatly affect microstructure and hardness in fusion zone and heat affected zone. As high aging temperature was used, the grain size also increased and M23C6 at the grain boundary decreased. This can result in decreased of hardness. Moreover excessive aging temperature can result in increasing MC carbide intensity in parent phase (austenite). It can also be observed that M23C6 at the grain boundary decreased due to high aging temperature. This resulted in decreasing of hardness of weld metal and heat affected zone. Experimental results showed that the aging temperature 705 0C aging time of 24 hours provided smaller grain size, suitable size and intensity of MC carbide resulting in higher hardness both in weld metal and HAZ.

Application of FIB/SEM/EBSD for Evaluation of Residual Strains and Their Relationship to Weld Metal Hydrogen Assisted Cold Cracking

2012 ◽  
Author(s):  
W. L. Costin ◽  
I. H. Brown ◽  
L. Green ◽  
R. Ghomashchi
Keyword(s):  
Residual Stresses ◽  
Weld Metal ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Ion Beam ◽  
Base Material ◽  
Welding Process ◽  
Cold Cracking ◽  
Predictive Methods ◽  
Residual Strains

Hydrogen assisted cold cracking (HACC) is a welding defect which may occur in the heat affected zone (HAZ) of the base metal or in the weld metal (WM). Initially the appearance of HACC was associated more closely with the HAZ of the base metal. However, recent developments in advanced steel processing have considerably improved the base material quality, thereby causing a shift of HACC to the WM itself. This represents a very serious problem for industry, because most of the predictive methods are intended for prevention of HACC in the HAZ of the base metal, not in the weld metal [1]. HACC in welded components is affected by three main interrelated factors, i.e. a microstructure, hydrogen concentration and stress level [2–4]. In general, residual stresses resulting from the welding process are unavoidable and their presence significantly influences the susceptibility of weld microstructures to cracking, particularly if hydrogen is introduced during welding [5]. Therefore various weldability tests have been developed over the years which are specifically designed to promote HACC by generating critical stress levels in the weld metal region due to special restraint conditions [4, 6–8]. These tests were used to develop predictive methods based on empirical criteria in order to estimate the cracking susceptibility of both the heat-affected zone and weld metal [4]. However, although the relationship between residual stress, hydrogen and HACC has received considerable attention, the interaction of residual stresses and microstructure in particular at microscopic scales is still not well understood [5, 9–21]. Therefore the current paper focuses on the development and assessment of techniques using Focused Ion Beam (FIB), Scanning Electron Microscopy (SEM) and Electron Backscatter Diffraction for the determination of local residual strains at (sub) micron scales in E8010 weld metal, used for the root pass of X70 pipeline girth welds, and their relationship to the WM microstructure. The measurement of these strains could be used to evaluate the pre-existing stress magnitudes at certain microstructural features [22].

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