Elevated Temperature Cracking Resistance of Ta-Bearing High Chromium Ni-Base Filler Metals

2017 ◽  
Author(s):  
Carolin Fink ◽  
John C. Lippold ◽  
Adam T. Hope ◽  
Steven McCracken
Keyword(s):  
Eutectic Reaction ◽  
Solidification Cracking ◽  
Good Resistance ◽  
Cracking Resistance ◽  
Solidification Temperature ◽  
High Chromium ◽  
Cast Pin Tear Test ◽  
Eutectic Constituent ◽  
Filler Metals ◽  
Mo Additions

Tantalum is investigated in this work as an alternative eutectic forming element to replace niobium in high chromium, Ni-base filler metals. Three experimental Ni-30Cr filler metals with additions of tantalum (Ta) and molybdenum (Mo) were studied in order to investigate eutectic constituent formation at the end of weld solidification and to determine weld metal cracking resistance. The cast pin tear test (CPTT) and the strain-to-fracture (STF) test were utilized to determine solidification cracking and ductility-dip cracking (DDC) susceptibility, respectively. Differences in the morphology of the eutectic constituents were observed as a function of Ta and Mo additions. Mo appears to participate in the eutectic reaction at the end of solidification, but does not affect the solidification temperature range. The experimental filler metals showed good resistance to solidification cracking and were remarkably resistant to DDC, especially at higher levels of Ta and Mo.

Hot Cracking Study of High Chromium Nickel-Base Weld Filler Metal 52MSS (ERNiCrFe-13) for Nuclear Applications

2010 ◽  
Author(s):  
Steven L. McCracken ◽  
Boian T. Alexandrov ◽  
John C. Lippold ◽  
Jeffrey W. Sowards ◽  
Adam T. Hope
Keyword(s):  
Filler Metal ◽  
Hot Cracking ◽  
Next Generation ◽  
Solidification Behavior ◽  
Solidification Temperature ◽  
High Chromium ◽  
Temperature Range ◽  
Solidification Temperature Range ◽  
Nickel Base ◽  
Filler Metals

High chromium nickel-base weld filler metals 52 (ERNiCrFe-7) and 52M (ERNiCrFe-7A) have in recent years replaced filler metal 82 (ERNiCr-3) for new fabrication and for repair applications in commercial nuclear power plants. Filler metals 52 and 52M are selected because they have excellent resistance to primary water stress corrosion cracking (PWSCC). Unfortunately, filler metals 52 and 52M exhibit a higher susceptibility to ductility-dip cracking (DDC) compared to filler metal 82. Filler metal 52MSS (ERNiCrFe-13) is a new high chromium nickel-base alloy with Nb and Mo added to improve resistance to ductility-dip cracking. Increasing Nb has in previous research been shown to widen the solidification temperature range in nickel-base alloys. A wider solidification temperature range can potentially increase susceptibility to hot cracking. This study investigated the solidification behavior and hot cracking susceptibility of three heats of 52MSS and compared the results to a heat of filler metal 52M and a heat of filler metal 52i. The solidification behavior and hot cracking susceptibility were investigated by an optimized Transvarestraint test and by a next generation Cast Pin Tear Test (CPTT). The solidification temperature range and eutectic transformations were measured by a patented Single Sensor Differential Thermal Analysis (SS-DTA) technique. This study showed that filler metal 52MSS was slightly more susceptible to hot cracking than 52M and 52i. This study also demonstrated that the next generation CPTT and SS-DTA technique are effective methods for evaluating the solidification behavior and hot cracking susceptibility of high chromium nickel-base weld filler metals.

Weldability Evaluation of High Chromium, Ni-Base Filler Metals Using the Cast Pin Tear Test

2016 ◽  
pp. 269-288 ◽  
Author(s):  
Eric Przybylowicz ◽  
Boian Alexandrov ◽  
John Lippold ◽  
Steven McCracken
Keyword(s):  
High Chromium ◽  
Cast Pin Tear Test ◽  
Filler Metals

CRONIFER 2328

Alloy Digest ◽  
1982 ◽  
Vol 31 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Heat Treating ◽  
Good Resistance ◽  
High Chromium ◽  
Good Corrosion Resistance ◽  
Temperature Performance ◽  
High Nickel

Abstract CRONIFER 2328 is a titanium-stabilized, high-chromium and high-nickel austenitic stainless steel with additions of molybdenum and copper. It exhibits good corrosion resistance against sulfuric and phosphoric acids. Also, it has good resistance against pitting and stress-corrosion cracking. Cronifer 2328 is used widely in the chemical industry for equipment and for the storage and transportation of various acids and solutions. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-411. Producer or source: Vereingte Deutsche Metallwerke AG.

Weld Solidification Cracking in Solid-Solution Strengthened Ni-Base Filler Metals

2008 ◽  
pp. 147-170 ◽  
Author(s):  
J.C. Lippold ◽  
J.W. Sowards ◽  
G.M. Murray ◽  
B.T. Alexandrov ◽  
A.J. Ramirez
Keyword(s):  
Solid Solution ◽  
Solidification Cracking ◽  
Weld Solidification Cracking ◽  
Filler Metals

Numerical Analysis of Aerospace Nickel-Based Single-Crystal Superalloy Weldability Part II: Nonequilibrium Solidification Behavior

2021 ◽  
Vol 1018 ◽  
pp. 33-41
Author(s):  
Zhi Guo Gao
Keyword(s):  
Single Crystal ◽  
Weld Pool ◽  
Heat Input ◽  
Dendrite Growth ◽  
Solidification Cracking ◽  
Solidification Temperature ◽  
Temperature Range ◽  
Solidification Temperature Range ◽  
Solid Liquid Interface ◽  
Nonequilibrium Solidification

The thermal metallurgical modeling by coupling of heat transfer model, dendrite selection model, columnar/equiaxed transition (CET) model and nonequilibrium solidification model was further developed to numerically analyze stray grain formation and solidification temperature range on the basis of three criteria of constitutional undercooling, marginal stability of planar front and minimum growth velocity during multicomponent nickel-based single-crystal superalloy weld pool solidification. It is indicated that the primary γ gamma phase microstructure development and solidification cracking susceptibility along the solid/liquid interface are symmetrically distributed throughout the weld pool in (001) and [100] welding configuration. The microstructure development and solidification cracking susceptibility along the solid/liquid interface are asymmetrically distributed in (001) and [110] welding configuration. Appropriate low heat input (low laser power and high welding speed) simultaneously minimizes stray grain formation, grain boundary misorientation and solidification temperature range in the vulnerable [100] dendrite growth region and beneficially maintains single-crystal nature of the material in the [001] epitaxial dendrite growth region to improve the cracking resistance, while high heat input (high laser power and low welding speed) increases the solidification cracking susceptibility to deteriorate weldability and weld integrity. The solidification temperature range in (001) and [110] welding configuration is detrimentally wider than that of (001) and [100] welding configuration due to crystallographic orientation of dendrite growth regardless of heat input. The mechanism of asymmetrical crystallography-dependant solidification cracking because of nonequilibrium solidification behavior is proposed. The elliptical and shallow weld pool shape is less susceptible to solidification cracking for successful crack-free laser welding. Moreover, the promising theoretical predictions agree well with the experiment results. The useful modeling is also applicable to other single-crystal superalloys with similar metallurgical properties during laser welding or laser cladding.

Weldability Evaluation of P87 and 230W Filler Metals in Alloy 230 to Grade P91 Steel Dissimilar Metal Weld

2017 ◽  
Author(s):  
Conner Sarich ◽  
Boian Alexandrov ◽  
Avraham Benatar ◽  
Jorge Penso ◽  
Jerry Kovacich
Keyword(s):  
Stress Relaxation ◽  
Filler Metal ◽  
Tensile Load ◽  
Solidification Cracking ◽  
P91 Steel ◽  
Dissimilar Metal ◽  
Dissimilar Metal Weld ◽  
Cracking Mode ◽  
Filler Metals ◽  
Metal Weld

The objective of this study was to perform comparative weldability evaluation of weld filler metals for an Alloy 230 / P91 steel dissimilar metal weld (DMW) that will be used in once through steam generator (OTSG) on an offshore oil platform. The weldability characteristics of filler metals EPRI P87 and Haynes 230W were evaluated using the cast pin tear test (CPTT) and a stress relaxation cracking (SRC) test in combination with metallurgical characterization using light optical and scanning electron microscopy. Solidification cracking susceptibility rankings generated with the CPTT showed that undiluted P87 filler metal had better resistance to solidification cracking than undiluted Alloy 230W. The SRC testing preformed in the Gleeble 3800™ thermo-mechanical simulator showed that none of the tested welds failed in stress relaxation cracking mode during simulated service at 600°C under constant displacement and tensile load at 90% of the high temperature yield strength. During the SRC testing, filler metal 230W exhibited some level of stress relaxation, while no evidence of stress relaxation was found in filler metal P87.

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