Creep-Rupture Properties, Resistance to Temper Embrittlement and to Attack by Hydrogen of a 1.4 Percent Mn — 0.25 Percent Mo — 0.03 Percent Cb Steel

1975 ◽  
Vol 97 (3) ◽  
pp. 234-244 ◽  
Author(s):  
T. Wada ◽  
D. L. Sponseller
Keyword(s):  
Carbon Steel ◽  
Rupture Strength ◽  
Temper Embrittlement ◽  
Charpy Impact ◽  
Creep Rupture ◽  
Hydrogen Attack ◽  
Boiler Steel ◽  
Rupture Ductility ◽  
Treated Carbon ◽  
Rupture Properties

A laboratory heat of an improved boiler steel containing 0.13 percent C, 1.36 percent Mn, 0.27 percent Mo, 0.03 percent Cb, and 0.010 percent N was prepared; creep-rupture properties, resistance to temper embrittlement and resistance to hydrogen attack were investigated. The rupture strength was much higher than that of carbon steel and columbium-treated carbon steel, but was somewhat lower than that of two European carbon-0.3 percent Mo boiler steels. Creep-rupture ductility was high. The experimental steel exhibited high toughness, especially in the normalized and stress-relieved condition. No temper embrittlement was induced by step-cooling normalized or normalized and stress-relieved material. Good resistance to hydrogen attack was revealed by tests in a hydrogen autoclave at a pressure of 1000 psi (6.9 N/mm2); the steel retained the original Charpy impact toughness after exposures up to 5000 hr at 900 deg F (480 deg C) and 500 hr at 1000 deg F (540 deg C). No blistering or fissuring were observed.

scholarly journals Effects of Lowering Si and Impurites on Temper-embrittlement and Creep Rupture Strength in Cr-Mo-V Steel for Turbine Rotor

1986 ◽  
Vol 72 (14) ◽  
pp. 1937-1943
Author(s):  
Masao SHIGA ◽  
Mitsuo KURIYAMA ◽  
Seishin KIRIHARA ◽  
Ryoichi KANEKO ◽  
Yasuo WATANABE
Keyword(s):  
Rupture Strength ◽  
Temper Embrittlement ◽  
Turbine Rotor ◽  
Creep Rupture ◽  
Creep Rupture Strength

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.

Capped End, Thin-Wall Tube Creep-Rupture Behavior for Type 316 Stainless Steel

1963 ◽  
Vol 85 (1) ◽  
pp. 71-86 ◽  
Author(s):  
G. H. Rowe ◽  
J. R. Stewart ◽  
K. N. Burgess
Keyword(s):  
Biaxial Tension ◽  
Rupture Life ◽  
Creep Rupture ◽  
Uniaxial Tensile ◽  
Thin Wall ◽  
Rupture Ductility ◽  
Statistical Argument ◽  
Stress Ratios ◽  
Rupture Properties ◽  
Rupture Behavior

The creep-rupture behavior of 34 capped end, thin-wall tubular specimens was correlated with results for 54 uniaxial tensile specimens in tests at 1350 F, 1500 F, and 1650 F. Basic tests established isotropy in creep-rupture properties as well as metallurgical stability for the material used in the study. Significant correlations of creep rate, rupture life, and rupture ductility were established for the cases of stress ratios 1/0 and 2/1 in the biaxial tension quadrant. Data from tests at 1500 F were evaluated for a statistical argument. This same material was subsequently utilized in a high temperature structures research program to be reported separately.

Welding Consumables for 2.25Cr-1Mo-V Refining Reactors

2017 ◽  
Author(s):  
Hideaki Takauchi ◽  
Tomoaki Nakanishi ◽  
Hidenori Nako
Keyword(s):  
High Temperatures ◽  
Temper Embrittlement ◽  
Pressure Vessels ◽  
Creep Rupture ◽  
Hydrogen Attack ◽  
Fine Carbide ◽  
Higher Temperature ◽  
Welding Consumables ◽  
Segregation Of Impurities ◽  
Welding Materials

Owing to the demands for larger-capacity reactor vessels in petroleum plants and higher temperature processes for the upgrade of heavy oil, enhanced 2.25Cr-1Mo, 2.25Cr-1Mo-V and 3Cr-1Mo-V steels, which suit both high temperatures and pressure operations, have been developed and used for heavy-wall pressure vessels since the 1990s. 2.25Cr-1Mo-V steel, which has very special mechanical properties, resistant to both hydrogen attack and embrittlement under high temperatures and pressure environments in particular, has been used since 2000. The specifications for 2.25Cr-1Mo-V steel pressure vessels, such as ASME Sec. VIII and API RP 934-A, have been established and reviewed to enhance the contents [1–2]. In this report, the transition of materials, the welding techniques for hydrocracking reactors and 2.25Cr-1Mo-V welding materials are introduced. Particularly, for these welding materials, in order to improve the creep rupture and temper embrittlement properties, the effectiveness of precipitates is discussed. It was found that fine carbide (MC) in crystal grains improves creep rupture lifetime and MC at the prior austenite (γ) grain boundaries inhibits temper embrittlement caused by the segregation of impurities.

scholarly journals Notch Creep Rupture Strength of Copper and Low Carbon Steel under Torsion

1974 ◽  
Vol 23 (246) ◽  
pp. 196-201 ◽  
Author(s):  
Kiyotsugu OHJI ◽  
Keiji OGURA ◽  
Shiro KUBO ◽  
Hisaaki YAMAKAGE
Keyword(s):  
Carbon Steel ◽  
Rupture Strength ◽  
Low Carbon Steel ◽  
Creep Rupture ◽  
Low Carbon ◽  
Creep Rupture Strength

Creep Rupture Ductility of Creep Strength Enhanced Ferritic Steels

2010 ◽  
Author(s):  
Kazuhiro Kimura ◽  
Kota Sawada ◽  
Hideaki Kushima
Keyword(s):  
Yield Stress ◽  
Creep Strength ◽  
Rupture Strength ◽  
Creep Rupture ◽  
Ferritic Steels ◽  
Creep Rupture Strength ◽  
Stress Regime ◽  
Rupture Ductility ◽  
Strength And Ductility

Creep rupture strength and ductility of Creep Strength Enhanced Ferritic steels of Grades 23, 91, 92 and 122 was investigated with particular emphasis on remarkable drop in the long-term. Large difference in creep rupture strength and ductility was observed on three heats of Grade 23 steels. Remarkable drop of creep rupture strength in the long-term of T91 was comparable to those of Grades 92 and 122. Remarkable drop in creep rupture ductility in a stress regime below 50% of 0.2% offset yield stress was observed on Grade T23 steel, however, that of Grade P23 steel did not indicate any degradation of creep rupture ductility. Higher creep rupture ductility of Grade P23 steel was considered to be caused by its lower creep strength than that of T23 steels. Creep rupture ductility of Grades 92 and 122 steels indicated rapid and drastic decrease with decrease in stress at 50% of 0.2% offset yield stress. Stress dependence of creep rupture ductility of Grades 92 and 122 steels was well described by a ratio of stress to 0.2% offset yield stress, regardless of temperature. On the other hand, large drop in creep rupture ductility of Grade 91 steel was observed only in the very low stress regime at 650°C. Alloying elements including impurities and changes in precipitates may influence on creep rupture ductility, however, remarkable drop in ductility of the steels cannot be explained by chemical composition and precipitates. High ductility in the high stress regime above 50% of 0.2% offset yield stress should be provided by easy plastic deformation, and it has been concluded that a remarkable drop in ductility in the low stress regime is derived from a concentration of creep deformation into a tiny recovered region formed at the vicinity of grain boundary.

The Influence of Nitrogen and Certain Other Elements on the Creep-Rupture Properties of Wholly Austenitic Type 304 Steel

1967 ◽  
Vol 89 (3) ◽  
pp. 517-524 ◽  
Author(s):  
P. D. Goodell ◽  
T. M. Cullen ◽  
J. W. Freeman
Keyword(s):  
Rupture Strength ◽  
Heat Treating ◽  
Creep Rupture ◽  
Published Data ◽  
Strengthening Effect ◽  
Full Effect ◽  
Titanium Aluminum ◽  
Rupture Properties ◽  
Type 304 ◽  
Percent Manganese

Experimental heats of Type 304 steel, compositionally balanced to be wholly austenitic and thus simulate the material used to produce seamless superheater tubing, were prepared to determine the influence of selected elements on the creep-rupture properties of this steel and thereby assess their possible contribution to the improvement in the elevated temperature properties which has been noted over the past years. Nitrogen is shown to increase the rupture strength at 1200 deg F of the wholly austenitic laboratory heats to a pronounced extent. Furthermore, almost the full effect of nitrogen was obtained after heat-treating at temperatures as low as 1750 deg F. Rupture strengths also increased with increasing carbon content although heat-treatment above 1750 deg F was necessary to obtain the maximum strengthening effect from the higher levels of this element. Nitrogen was a somewhat more effective strengthener than carbon, the rupture strengths correlating with (%C) + 1.25 × (%N). Small amounts of titanium, aluminum, boron, copper, and molybdenum had no or at most only minor effects on the properties. More than 0.1 percent manganese was necessary for good rupture properties but otherwise had little effect at levels up to at least 1.5 percent. Published data for commercial heats fitted the correlation developed from the laboratory heats. The generally higher level of the rupture strength data for Type 304 austenitic steel published since the early 1950’s appears to be closely related to higher levels of nitrogen. The data indicate that it is extremely important to control nitrogen content to obtain expected creep-rupture properties at 1200 deg F.

Short-Time Tensile and Long-Time Creep-Rupture Properties of the HK-40 Alloy and Type 310 Stainless Steel at Temperatures to 2000 F

1967 ◽  
Vol 89 (3) ◽  
pp. 465-478 ◽  
Author(s):  
J. A. VanEcho ◽  
D. B. Roach ◽  
A. M. Hall
Keyword(s):  
Stainless Steel ◽  
Rupture Strength ◽  
Creep Rupture ◽  
Eutectic Carbides ◽  
Heat Resistant Alloy ◽  
310 Stainless Steel ◽  
The Matrix ◽  
Long Time ◽  
Short Time ◽  
Rupture Properties

The short-time tensile properties of the A CI Type HK-40 cast heat-resistant alloy and AISI Type 310 wrought stainless steel were investigated from room temperature to 2000 F. The creep-rupture properties of the HK-40 alloy were studied in the range of 1400 to 2000 F for times long enough to permit extrapolation to 100,000 hr. In addition, the creep-rupture properties of Type 310 were investigated at 1800 to 2000 F, and observations were made of the microstructural changes that occurred in the two materials during creep exposure. The Type 310 material tended to have a higher yield strength and ultimate tensile strength at moderate temperatures than the HK-40; however, from 1200 to 2000 F, the HK-40 was the stronger. The Type 310 was more ductile at all temperatures. The HK-40 displayed about twice the rupture strength of the Type 310 at each test temperature. On the basis of comparable minimum creep rates, the HK-40 showed five to six times the strength of the Type 310 at the same temperature. During exposure at the lower temperatures, chromium carbides precipitated in finely dispersed form in the matrix of the HK-40; isolated islands of sigma phase also tended to form. At high temperatures, the primary eutectic carbides in the HK-40 alloy tended to spheroidize; and both materials absorbed nitrogen from the atmosphere, needles of chromium nitride forming in the matrix.

Mechanical Properties of New Grades of FE-3Cr-W Alloys

2004 ◽  
Author(s):  
Vinod K. Sikka ◽  
Ronald L. Klueh ◽  
Philip J. Maziasz ◽  
Suresh Babu ◽  
Michael L. Santella ◽  
...  
Keyword(s):  
Rupture Strength ◽  
National Laboratory ◽  
Charpy Impact ◽  
Creep Rupture ◽  
Good Combination ◽  
Creep Rupture Strength ◽  
Oak Ridge ◽  
Grade 91 ◽  
Hot Rolled ◽  
Rolled Plates

This paper describes the development of two new grades of Fe-3Cr-3W(Mo) alloys at the Oak Ridge National Laboratory. The two grades are designated as A and B. The higher strength Grade B differs from Grade A in that it contains 0.10 wt % Ta. Both grades, when tested in normalized and tempered conditions, show a good combination of tensile strength and Charpy impact properties. Tensile properties of both A and B are over 150 MPa (20 ksi) higher than the highest strength commercial alloy T23. Grade B has higher creep-rupture strength than the T23 steel for the entire temperature range from 540 to 650°C. Grade B also exceeds creep-rupture strength of modified 9Cr-1Mo alloy (Grade 91) up to 615°C. Grade A exceeds the creep-rupture strength of T23 steel up to 600°C and match its values at the higher temperatures. Both grades have been scaled up to 50-ton-size commercial heats and processed into forgings and hot-rolled plates and bars.

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