High Temperature Properties and Constitutive Equations for 1 Cr-1/2 Mo Steel

1978 ◽  
Vol 100 (3) ◽  
pp. 246-255 ◽  
Author(s):  
Saphura S. Long
Keyword(s):  
Creep Rate ◽  
Constitutive Equation ◽  
Constitutive Equations ◽  
Minimum Creep Rate ◽  
Room Temperature ◽  
Tensile Tests ◽  
Creep Rupture ◽  
Secondary Creep ◽  
Stress Strain ◽  
Plastic Strain Range

This paper presents the tensile, creep, rupture, and fatigue properties of 1 Cr-1/2 Mo steel. Tensile tests were conducted over a temperature range of 70–1150 F (21 to 621 C). Creep-rupture tests were run for the stress range of 10–56 ksi (69 to 386 MPa) at temperatures of 850 to 1150 F (454 to 621 C) and the strain-controlled fatigue tests were run to 145,000 cycles at room temperature. Results of the tensile tests are presented as stress-strain curves and as constitutive equations. The parameters in the equations were obtained by a nonlinear least-squares technique assuming an origin offset power law formulation of true stress as a function of true strain. The creep analysis resulted in a creep constitutive equation, isochronous stress-strain curves, and correlations between rupture time, time to onset of tertiary creep, and minimum creep rate. The constitutive equation is a two-term rational polynomial with a steady-state term which describes primary plus secondary creep. Isochronous stress-strain curves were developed from the creep equation and extrapolated to 100,000 hr. Over the measured range, the isochronous curves showed excellent agreement with the actual data. In absolute strength level, both the rupture stress and minimum creep rate data show that this particular heat of material lies in the upper part of the scatter band for 1 Cr-1/2 Mo steel. The room temperature cyclic stress-strain curves show the alloy strain softens in the low strain region and strain hardens in the high-strain region. The fatigue behavior is typified by a linear relationship between both elastic and plastic strain range and cycles to failure on a log-log basis. The fatigue results conform reasonably well to predictions from Manson’s method of universal slopes.

Creep Deformation Behavior and Microstructural Degradation During Creep of Pre-Strained 25Cr-20Ni-Nb-N Steel

2007 ◽  
Author(s):  
Nobuhiko Saito ◽  
Nobuyoshi Komai
Keyword(s):  
Creep Rate ◽  
Creep Deformation ◽  
Deformation Behavior ◽  
Minimum Creep Rate ◽  
Strengthening Mechanism ◽  
Creep Rupture ◽  
Microstructural Degradation ◽  
Solution Treated ◽  
Long Time ◽  
Strained Materials

The purpose of this study is to clarify the creep deformation behavior and microstructural degradation during creep of pre-strained 25Cr-20Ni-Nb-N steel (TP310HCbN), which has the highest creep strength among austenite stainless steels used for boiler tubes. The creep rupture strengths of the 20% pre-strained materials tested at 650°C under 210 MPa and 180 MPa were higher than those of solution-treated materials. However, the long time creep rupture strengths of the 20% pre-strained materials tested at 700°C and 750°C were lower than those of solution-treated materials. Thus, the creep strengths of the prestrained materials depend on test temperature and stress. Furthermore, the minimum creep rate of the 20% pre-strained materials and re-solution-treated materials tested at 650°C under 300MPa were 1.2 × 10−9 and 1.6 × 10−8 s−1, respectively. Thus, the minimum creep rate of the 20% pre-strained materials was lower than for re-solution-treated materials. The creep strengthening mechanism of the pre-strained materials at 650°C was considered to be that high-density dislocations were maintained until the late stage of creep. On the other hand, the creep rupture strengths of the 20% pre-strained materials were lower than those of solution-treated materials tested at over 700°C because of agglomeration and coarsening of precipitates and the recovery of dislocations.

On Time-Temperature Parameters for Correlation of Creep-Rupture Data in Stainless Steel Weldments

1978 ◽  
Vol 100 (3) ◽  
pp. 319-332 ◽  
Author(s):  
W. E. White ◽  
Iain Le May
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Creep Rate ◽  
Creep Rupture ◽  
Rupture Time ◽  
Function Approach ◽  
Secondary Creep ◽  
Rupture Data ◽  
The Relationship ◽  
Secondary Creep Rate

The Manson-Haferd, Larson-Miller, and Orr-Sherby-Dorn time-temperature parameters were applied to creep-rupture data obtained from testing two batches of austenitic stainless steel weldments. It was found that none of these correlated the data satisfactorily. A new parameter, based on a modification of one proposed originally by Manson and by Goldhoff and Sherby, was found to adequately correlate the data. The Minimum-Commitment, Station-Function Approach of Manson and Ensign was also applied, the results of which supported those obtained from the analysis made using the parameters listed above. Finally, from the relationship between rupture-time and secondary creep-rate, it is suggested that the form of the rupture data may be useful in predicting the physical basis for creep.

Time to Initiation of Tertiary Creep Property of Grade 91 Steels

2016 ◽  
Author(s):  
Kazuhiro Kimura ◽  
Kota Sawada
Keyword(s):  
Creep Rate ◽  
Minimum Creep Rate ◽  
Rupture Life ◽  
Creep Rupture ◽  
Tertiary Creep ◽  
Time To Initiation ◽  
Wide Range ◽  
Minimum Stress ◽  
Grade 91

Creep deformation property of Grade 91 steels was analyzed on more than 370 creep curves over a wide range of time to rupture from about 10 hours to beyond 100,000 hours, in order to evaluate time to 1% total strain, time to minimum creep rate and time to initiation of tertiary creep. Time to initiation of tertiary creep was assessed as a 0.2% offset with a slope of minimum creep rate. It is difficult to determine time to minimum creep rate precisely, which is a basis of 0.2% offset, however, it has been confirmed that time to initiation of tertiary creep is not sensitive to the time when the creep rate indicates minimum value. Life ratio of 1% total strain time against creep rupture time increases up to about 60% with increase of temperature and decrease of stress. Life ratio of time to initiation of tertiary creep also tends to increase with decrease in stress. However, change of it is in a range of 50 to 60% of creep rupture life over a wide range of creep rupture life from 10 hours to 100,000 hours, and it is not sensitive to creep test temperature. Over a range of temperatures from 500 to 600°C and up to about 200,000 hours, a temperature and time-dependent stress intensity limit, St is controlled by 67% of minimum stress to rupture. However, a difference between 67% of minimum stress to rupture and 80% of minimum stress to initiation of tertiary creep decreases with increases in temperature and time, and both values approach each other in the long-term beyond about 100,000 hours at 600°C. In the long-term beyond about 10,000 hours at 650°C, St is controlled by 80% of minimum stress to initiation of tertiary. The stable life fraction of time to initiation of tertiary creep establish a reliability of a temperature and time-dependent stress intensity limit value.

Constitutive Equations for Tensile and Creep Behavior of a 9 Cr-1 MO Steel

1975 ◽  
Vol 97 (4) ◽  
pp. 258-263
Author(s):  
F. V. Ellis ◽  
J. E. Bynum ◽  
B. W. Roberts
Keyword(s):  
Constitutive Equation ◽  
Test Data ◽  
Constitutive Equations ◽  
Tensile Tests ◽  
Temperature Dependent ◽  
Creep Tests ◽  
Creep Properties ◽  
Hardening Mechanism ◽  
Strain Relationship ◽  
Analysis Computer

This paper describes an investigation of the tensile and creep properties of annealed 9 Cr-1 Mo steel. Tensile tests were conducted at temperatures from 70 to 1050 F while creep tests were conducted at 750, 850, 950, and 1050 F with stresses from 4 to 52 ksi. From the tensile test data, a constitutive equation was developed for the stress-plastic strain relationship. This equation was based on a two-stage hardening mechanism and combined power law and exponential functions. From the creep test data, isochronous stress-strain curves were constructed out to 104 hr. These curves were extrapolated to 105 hr and to lower stresses using a parametric analysis procedure. Additionally, a creep constitutive equation capable of describing the total creep curve, including the tertiary region, was developed. This equation, having three stress and temperature dependent parameters predicted creep curves which were in good agreement with the actual curves. Both the time-independent (tensile) and time-dependent (creep) constitutive equations are suitable for use in finite element stress analysis computer programs.

scholarly journals A study of the Cu0.95Al0.05 alloy: stress-strain curve and microstructure

2018 ◽  
Vol 20 (2) ◽  
Author(s):  
Emilio Medrano ◽  
Mauro Quiroga ◽  
Felipe A. Reyes
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Strain Curve ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Metal Alloys ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Electrolytic Copper ◽  
Mechanical Traction

After fabricating five metallographic specimens of the Cu0.95Al0.05 alloy from electrolytic copper and aluminum, these ones were both microstructurally characterized by using a metallographic optical microscope at room temperature and subjected to mechanical traction in order to chart the stress-strain curve. From the characterization, it has been found out that the Cu0.95Al0.05 microstructure is composed of a single phase, and from the tensile tests, it has been obtained its rupture point, 249.361 MPa. The obtained results were explained in the framework of the theory of metals and metal alloys.

Experimental Investigation on 2D and 3D Braided C/SiC Composites

2006 ◽  
Vol 326-328 ◽  
pp. 1685-1688 ◽  
Author(s):  
Bo Wang ◽  
Gui Qiong Jiao ◽  
Yan Jun Chang ◽  
Wen Ge Pan
Keyword(s):  
Acoustic Emission ◽  
Room Temperature ◽  
Tensile Tests ◽  
Damage Evaluation ◽  
Stress Strain ◽  
Pull Out ◽  
Sic Composites ◽  
2D And 3D ◽  
Zigzag Shape ◽  
Ae Counts

Tensile tests of two-dimensionally braided C/SiC composites and three-dimensionally braided C/SiC composites had been carried out at room temperature. Some specimens had been unloaded during experiments. Acoustic Emission signals also had been collected during experiments. The following conclusions were arrived. The stress-strain curves of these two materials were of nonlinear characters, and there were no obvious linear segments on those curves. Failure characters of these two materials were different: There appeared ply pull-out for 2D braided C/SiC specimens and there appeared zigzag shape for 3D braided C/SiC specimens. Stress-strain curves of loading-unloading tests and Acoustic Emission signals of those two materials showed damage evaluation during tests. There were different AE counts and AE energy characters between two materials.

Experimental Study on Low Temperature Mechanical Properties of HTPB Propellant

2013 ◽  
Vol 310 ◽  
pp. 124-128 ◽  
Author(s):  
Xiao Jun Zhang ◽  
Xin Long Chang ◽  
Shi Ying Zhang ◽  
Jie Tang Zhu
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Tensile Test ◽  
Room Temperature ◽  
Maximum Stress ◽  
Tensile Tests ◽  
Maximum Tensile Stress ◽  
Uniaxial Tensile ◽  
Stress Strain ◽  
Htpb Propellant

In order to investigate low temperature mechanical characteristics of HTPB (hydroxy-terminated polybutadiene binder) propellant, uniaxial tensile tests at both the low temperature and room temperature after short storage at low temperature were conducted and SEM (scanning electron microscopy) was used to observe fracture surfaces. The mechanical properties and stress-strain curves were obtained. The experimental results show that matrix tearing and particle brittle fracture occur in low temperature tensile test, but only particle/matrix interface de-wetting in room temperature tensile test. Low temperature stress-strain curves of propellant appear obviously yield region, and the yield degree is involved to the low temperature value. The low temperature mechanical properties such as maximum tensile stress, elastic modulus and strain at maximum stress against temperature are different from room temperature mechanical properties.

Creep-Rupture Behavior of Six Candidate Stirling Engine Superalloys Tested in Air

1984 ◽  
Vol 106 (1) ◽  
pp. 50-58 ◽  
Author(s):  
S. Bhattacharyya
Keyword(s):  
Creep Rate ◽  
Minimum Creep Rate ◽  
Rupture Life ◽  
Stirling Engine ◽  
Creep Rupture ◽  
Similar Data ◽  
Alloy 800H ◽  
Different Temperatures ◽  
Cast Alloys ◽  
Rupture Behavior

The creep-rupture behavior of six candidate Stirling engine iron-base superalloys was determined in air. The alloys included four wrought alloys (A-286, Alloy 800H, N-155, and 19-9DL) and two cast alloys (CRM-6D and XF-818). The specimens were tested to rupture for times up to 3000 h at 650° to 925°C. Rupture life (tr), minimum creep rate (ε˙m), and time to 1 percent creep strain (t0.01), were statistically analyzed as a function of stress and temperature. Estimated stress levels at different temperatures to obtain 3500 h tr and t0.01 lives were determined. These data will be compared with similar data being obtained under 15 MPa hydrogen.

Compressive Deformation of Cast AM60B Mg Alloy at Elevated Temperatures

2007 ◽  
Vol 546-549 ◽  
pp. 271-274
Author(s):  
Han Xue Cao ◽  
Si Yuan Long ◽  
Hui Min Liao
Keyword(s):  
Constitutive Equation ◽  
Compression Ratio ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Mg Alloy ◽  
Compressive Deformation ◽  
Stress Strain ◽  
Empirical Results ◽  
Experimental Findings ◽  
Good Agreement

The deformability of cast AM60B Mg alloy is investigated by compressing AM60B cast ingots at elevated temperatures. The empirical results show that cast AM60B Mg alloy was brittle at room temperature and prone to cracking during compression, however at the temperatures ranging from 573 to 673K, excellent deformability is demonstrated with around 70% compression ratio. The compressive deformation constitutive equation for AM60B Mg alloy at elevated temperatures was established. The stress-strain relationships predicted at elevated temperatures show good agreement with experimental findings.

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