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.

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.

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.

scholarly journals On the impact of post weld heat treatment on the microstructure and mechanical properties of creep resistant 2.25Cr–1Mo–0.25V weld metal

2021 ◽  
Author(s):  
Hannah Schönmaier ◽  
Christian Fleißner-Rieger ◽  
Ronny Krein ◽  
Martin Schmitz-Niederau ◽  
Ronald Schnitzer
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Weld Metal ◽  
Elevated Temperatures ◽  
Stress Rupture ◽  
Pressure Vessels ◽  
Post Weld Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
The Impact ◽  
Weld Heat

AbstractCreep resistant low-alloyed 2.25Cr-1Mo-0.25V steel is typically applied in hydrogen bearing heavy wall pressure vessels in the chemical and petrochemical industry. For this purpose, the steel is often joined via submerged-arc welding. In order to increase the reactors efficiency via higher operating temperatures and pressures, the industry demands for improved strength and toughness of the steel plates and weldments at elevated temperatures. This study investigates the influence of the post weld heat treatment (PWHT) on the microstructure and mechanical properties of 2.25Cr-1Mo-0.25V multi-layer weld metal aiming to describe the underlying microstructure-property relationships. Apart from tensile, Charpy impact and stress rupture testing, micro-hardness mappings were performed and changes in the dislocation structure as well as alterations of the MX carbonitrides were analysed by means of high resolution methods. A longer PWHT-time was found to decrease the stress rupture time of the weld metal and increase the impact energy at the same time. In addition, a longer duration of PWHT causes a reduction of strength and an increase of the weld metals ductility. Though the overall hardness of the weld metal is decreased with longer duration of PWHT, PWHT-times of more than 12 h lead to an enhanced temper resistance of the heat-affected zones (HAZs) in-between the weld beads of the multi-layer weld metal. This is linked to several influencing factors such as reaustenitization and stress relief in the course of multi-layer welding, a higher fraction of larger carbides and a smaller grain size in the HAZs within the multi-layer weld metal.

NIMROD 617KS

Alloy Digest ◽  
2002 ◽  
Vol 51 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Weld Metal ◽  
Tensile Properties ◽  
Base Metal ◽  
Heat Treating ◽  
Nominal Composition

Abstract Nimrod 617KS is an Inconel-type consumable with a nominal composition of nickel, 24% Cr,12% Co, and 9% Mo and is used to join UNS N06617 and Nicrofer 6023 to themselves. The alloy is designed for high-temperature service and is often used as the weld metal in dissimilar cases to ensure the weld is as strong as the base metal. This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on heat treating and joining. Filing Code: Ni-583. Producer or source: Metrode Products Ltd.

THERMO-SPAN ALLOY

Alloy Digest ◽  
1994 ◽  
Vol 43 (2) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Fatigue Resistance ◽  
Thermal Fatigue ◽  
Rupture Strength ◽  
Stress Rupture ◽  
Heat Treating ◽  
Thermal Fatigue Resistance ◽  
Stress Rupture Strength

Abstract THERMO-SPAN ALLOY is a precipitation-hardenable superalloy with a low coefficient of expansion combined with tensile and stress-rupture strength. Thermal fatigue resistance is inherent. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on forming and heat treating. Filing Code: FE-105. Producer or source: Carpenter.

TECHALLOY WASPALOY

Alloy Digest ◽  
1977 ◽  
Vol 26 (4) ◽  
Keyword(s):  
Elevated Temperatures ◽  
Rupture Strength ◽  
Stress Rupture ◽  
High Strength ◽  
Heat Treating ◽  
Age Hardening ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Nickel Base ◽  
Corrosion And Oxidation

Abstract TECHALLOY WASPALOY, a nickel-base austenitic precipitation-hardenable alloy, derives its high strength at elevated temperatures from additions of the solid-solution strengthening elements molybdenum, cobalt and chromium and from aluminum and titanium which produce age hardening. Boron and zirconium additions also have been made to obtain optimum stress-rupture strength. It has excellent strength and good resistance to corrosion and oxidation at least to 1600 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-243. Producer or source: Techalloy Company Inc..

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.

scholarly journals Influence of the Heat Input on the Dendritic Solidification Structure and the Mechanical Properties of 2.25Cr-1Mo-0.25V Submerged-Arc Weld Metal

2021 ◽  
Author(s):  
Hannah Schönmaier ◽  
Ronny Krein ◽  
Martin Schmitz-Niederau ◽  
Ronald Schnitzer
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Heat Input ◽  
Stress Rupture ◽  
Pressure Vessels ◽  
Rupture Time ◽  
Solidification Structure ◽  
Welding Parameters ◽  
Austenite Grain Size ◽  
Submerged Arc

AbstractThe alloy 2.25Cr-1Mo-0.25V is commonly used for heavy wall pressure vessels in the petrochemical industry, such as hydrogen reactors. As these reactors are operated at elevated temperatures and high pressures, the 2.25Cr-1Mo-0.25V welding consumables require a beneficial combination of strength and toughness as well as enhanced creep properties. The mechanical properties are known to be influenced by several welding parameters. This study deals with the influence of the heat input during submerged-arc welding (SAW) on the solidification structure and mechanical properties of 2.25Cr-1Mo-0.25V multilayer metal. The heat input was found to increase the primary and secondary dendrite spacing as well as the bainitic and prior austenite grain size of the weld metal. Furthermore, it was determined that a higher heat input during SAW causes an increase in the stress rupture time and a decrease in Charpy impact energy. This is assumed to be linked to a lower number of weld layers, and therefore, a decreased amount of fine grained reheated zone if the multilayer weld metal is fabricated with higher heat input. In contrast to the stress rupture time and the toughness, the weld metal’s strength, ductility and macro-hardness remain nearly unaffected by changes of the heat input.

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.

Sign in / Sign up

Export Citation Format

Share Document