Assessment of the propensity of low creep ductility for optimized Grade 92 steel

2018 ◽  
Author(s):  
Lizhen Tan
Keyword(s):  
Creep Ductility ◽  
Grade 92 Steel

KUBOTA ALLOY KHR32C

Alloy Digest ◽  
1999 ◽  
Vol 48 (6) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Alloy 800H ◽  
Creep Ductility

Abstract Kubota alloy KHR32C is often regarded as the cast version of Fe-Ni-Cr alloy 800H except it uses niobium as a strengthening agent. The moderately priced alloy has good creep ductility and is available in many cast forms. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on casting. Filing Code: SS-746. Producer or source: Kubota Metal Corporation.

Estimation of Creep Crack Growth Properties Using Circumferential Notched Round Bar Specimen for 12CrWCoB Rotor Steel

2005 ◽  
Vol 297-300 ◽  
pp. 397-402
Author(s):  
Je Chang Ha ◽  
Joon Hyun Lee ◽  
Masaaki Tabuchi ◽  
A.Toshimitsu Yokobori Jr.
Keyword(s):  
Crack Growth ◽  
Axial Stress ◽  
Creep Crack Growth ◽  
Turbine Rotor ◽  
Rotor Steel ◽  
Creep Ductility ◽  
Crack Growth Behaviour ◽  
Creep Crack ◽  
Round Bar ◽  
Growth Properties

Most heat resisting materials in structural components are used under multi-axial stress conditions and under such conditions ductile materials often exhibit brittle manner and low creep ductility at elevated temperature. Creep crack initiation and growth properties are also affected by multi-axial stress and it is important to evaluate these effects when laboratory data are applied to structural components. Creep crack growth tests using circumferential notched round bar specimens are a simple method to investigate multi-axial stress effects without using complicated test facilities. Creep crack growth tests have been performed using a 12CrWCoB turbine rotor steel. In order to investigate the effects of multi-axial stress on creep crack growth properties, the tests were conducted for various notch depths at 650°C. The circumferential notched round bar specimen showed brittle crack growth behaviour under multi-axial stress conditions. Creep crack growth rate was characterized in terms of the C* parameter. A 12CrWCoB turbine rotor steel has been tested using circumferential notched round bar specimens with different multi-axiality. Circumferential notched round bar specimens show increased brittle creep crack growth behaviour due to the multi-axial stress condition. Creep crack growth properties could be predicted by allowing for the decrease of creep ductility under multi-axial conditions.

scholarly journals Influence of microstructure on cavitation in the heat affected zone of a Grade 92 steel weld during long-term high temperature creep

2020 ◽  
Vol 170 ◽  
pp. 110663 ◽  
Author(s):  
X. Xu ◽  
J.A. Siefert ◽  
J.D. Parker ◽  
R.C. Thomson
Keyword(s):  
High Temperature ◽  
Heat Affected Zone ◽  
High Temperature Creep ◽  
Steel Weld ◽  
Temperature Creep ◽  
Grade 92 Steel

The development of metallurgically stable magnesium-zirconium alloys with high creep ductility

1963 ◽  
Vol 8 (2) ◽  
pp. 179-186 ◽  
Author(s):  
E.A. Walker ◽  
P.A. Fisher
Keyword(s):  
Zirconium Alloys ◽  
Creep Ductility

Long-Term Creep Ductility Minima in 12%CrMoV Steel

1991 ◽  
pp. 146-159 ◽  
Author(s):  
R. Timmins ◽  
P. F. Aplin
Keyword(s):  
Creep Ductility ◽  
Term Creep

Creep Failure Simulations for 316H at 550°C

2012 ◽  
Author(s):  
Nak Hyun Kim ◽  
Yun Jae Kim ◽  
Catrin M. Davies ◽  
Kamran M. Nikbin ◽  
David W. Dean
Keyword(s):  
Experimental Data ◽  
Damage Model ◽  
Creep Damage ◽  
Inelastic Strain ◽  
Compact Tension ◽  
Creep Failure ◽  
Creep Ductility ◽  
Summation Rule ◽  
Creep Damage Model ◽  
Damage Summation

In this work a method to simulate failure due to creep is proposed using finite element damage analysis. The creep damage model is based on the creep ductility exhaustion concept. Incremental damage is defined by the ratio of incremental inelastic (plastic & creep) strain and multi-axial ductility. A simple linear damage summation rule is applied. When accumulated damage becomes unity, element stresses are reduced to almost zero to simulate progressive crack growth. The model is validated through comparison with experimental data on various sized compact tension, C(T), specimens of 316H stainless steel at 550 °C. The influence of the inelastic strain rate on the uniaxial ductility is considered. Good agreement is found between the simulated results and the experimental data.

Progress in the Design of an Improved High-Temperature 1 Percent CrMoV Rotor Steel

1990 ◽  
Vol 112 (1) ◽  
pp. 99-115 ◽  
Author(s):  
R. L. Bodnar ◽  
J. R. Michael ◽  
S. S. Hansen ◽  
R. I. Jaffee
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Room Temperature ◽  
Rupture Strength ◽  
Temper Embrittlement ◽  
Creep Rupture ◽  
Rotor Steel ◽  
Creep Rupture Strength ◽  
Austenitizing Temperature ◽  
Creep Ductility

Silicon-deoxidized, tempered bainitic 1 percent CrMoV steel is currently used extensively for high-temperature steam turbine rotor forgings operating at temperatures up to 565°C due to its excellent creep rupture properties and relative economy. There is impetus to improve the creep rupture strength of this steel while maintaining its current toughness level and vice versa. The excellent creep rupture ductility of the low Si version of this steel allows the use of a higher austenitizing temperature or tensile strength level for improving creep rupture strength without loss in creep ductility or toughness. When the tensile strength of this steel is increased from 785 to 854 MPa, the creep rupture strength exceeds that of the more expensive martensitic 12CrMoVCbN steel currently used for high-temperature rotor applications where additional creep rupture strength is required. The toughness of 1 percent CrMoV steel is improved by lowering the bainite start (Bs) temperature in a “superclean” base composition which is essentially free of Mn, Si, P, S, Sb, As and Sn. The Bs temperature can be lowered through the addition of alloying elements (i.e., C, Ni, Cr, and Mo) and/or increasing the cooling rate from the austenitizing temperature. Using these techniques, the 50 percent FATT can be lowered from approximately 100°C to below room temperature, which provides the opportunity to eliminate the special precautionary procedures currently used in the startup and shutdown of steam turbines. The most promising steels in terms of creep rupture and toughness properties contain 2.5 percent Ni and 0.04 percent Cb (for austenite grain refinement and enhanced tempering resistance). In general, the creep rupture strength of the superclean steels equals or exceeds that of the standard 1 percent CrMoV steel. In addition, the superclean steels have not been found to be susceptible to temper embrittlement, nor do they alter the room temperature fatigue crack propagation characteristics of the standard 1 percent CrMoV steel. These new steels may also find application in combination high-temperature-low-temperature rotors and gas turbine rotors.

Creep ductility of cold-worked Zr-2.5 wt% Nb and Zircaloy-2 tubes in-reactor

1981 ◽  
Vol 96 (3) ◽  
pp. 297-304 ◽  
Author(s):  
E.F. Ibrahim
Keyword(s):  
Creep Ductility ◽  
Cold Worked

Mixed Mode Loading of an Interface Crack Subjected to Creep Conditions

2003 ◽  
Author(s):  
Ali P. Gordon ◽  
David L. McDowell
Keyword(s):  
Transition Layer ◽  
Mixed Mode ◽  
Elevated Temperatures ◽  
Numerical Solutions ◽  
Crack Tip ◽  
Functionally Graded ◽  
Pure Mode ◽  
Mixed Mode Loading ◽  
Creep Ductility ◽  
Interface Cracks

Interface cracks are seldom subjected to pure Mode I or pure Mode II conditions. Stationary interface cracks between two distinct, bonded elastic-creep materials subjected to remotely applied mixed mode loading are simulated. The finite element method (FEM) is used to examine crack tip fields and candidate driving force parameters for crack growth. Plane strain conditions are assumed. In most cases a functionally graded transition layer is included between the two materials. Examples of such systems include weld metal (WM) and base metal (BM) interfaces in welded or repaired boiler components subjected to elevated temperatures. Numerical solutions based on the asymptotic fields of the homogeneous and heterogeneous Arcan-type specimens are presented. Creep ductility-based damage models are used to predict the initial crack propagation trajectory. The incorporation of functionally graded transition layer regions affects the evolution of time-dependent stress components in the vicinity of the crack tip. The magnitude and direction of crack tip propagation can then be optimized with respect to interface properties.

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