Creep-Rupture Properties of Centrifugally Cast 1 1/4 Cr-1/2 Mo Alloy Steel Pipe

1966 ◽  
Vol 88 (4) ◽  
pp. 755-761
Author(s):  
C. L. Dotson ◽  
C. K. Donoho
Keyword(s):  
Creep Rate ◽  
Alloy Steel ◽  
Minimum Creep Rate ◽  
Rupture Strength ◽  
Cast Alloy ◽  
Creep Rupture ◽  
Steel Pipe ◽  
Published Data ◽  
Centrifugally Cast ◽  
Rupture Properties

The creep-rupture properties of tensile specimens made from 1 1/4 Cr-1/2 Mo centrifugally cast alloy steel pipe, conforming to ASTM A426-CP11, were evaluated at 1000, 1100, and 1200 F. At 1000 F, the pipe was evaluated in two normalized-and-tempered conditions, and at 1100 and 1200 F, in one normalized-and-tempered condition. Specimens were loaded to produce rupture in time ranging from less than 100 to about 2000 hr for determination of the minimum creep rate and the creep-rupture strength, and at lower loads to obtain additional minimum creep rate data. The rupture strength and minimum creep rate of the centrifugally cast pipe were compared to similar properties for the alloy in statically cast and wrought forms. Stresses required to produce a minimum creep rate of 10−5 percent/hr and rupture in 100,000 hr were compared to allowable design stresses specified by the ASME Boiler and Pressure Vessel Code and American Standards Association Specifications B31.1, Pressure Piping, and B31.3, Petroleum Refinery Piping. In both heat-treated conditions evaluated, the minimum creep rate of the pipe compared favorably with published data for the alloy in noncentrifugally cast forms and with the allowable stresses set by the ASME and ASA codes.

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.

WISCALLOY 25-35Nb

Alloy Digest ◽  
1996 ◽  
Vol 45 (9) ◽  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Creep Rupture ◽  
Centrifugally Cast ◽  
Heat Resistant ◽  
Rupture Properties

Abstract Wiscalloy 25-35Nb is a high-temperature cast heat-resistant stainless steel with good creep-rupture properties. The alloy is centrifugally cast and is often used as petrochemical furnace tubing. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on casting and joining. Filing Code: SS-654. Producer or source: Wisconsin Centrifugal.

Long Term Creep Properties of a Die-Cast Mg-Al-Ca Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 163-166
Author(s):  
Yoshihiro Terada ◽  
Tatsuo Sato
Keyword(s):  
Creep Rate ◽  
Magnesium Alloys ◽  
Cast Alloy ◽  
Rupture Life ◽  
Testing Temperature ◽  
Creep Rupture ◽  
Die Cast ◽  
Cast Magnesium Alloys ◽  
Term Creep ◽  
Cast Magnesium

Creep rupture tests were performed for a die-cast Mg-Al-Ca alloy AX52 (X representing calcium) at 29 kinds of creep conditions in the temperature range between 423 and 498 K. The creep curve for the alloy is characterized by a minimum in the creep rate followed by an accelerating stage. The minimum creep rate (ε& m) and the creep rupture life (trup) follow the phenomenological Monkman-Grant relationship; trup = C0 /ε& m m. It is found for the AX52 die-cast alloy that the exponent m is unity and the constant C0 is 2.0 x 10-2, independent of creep testing temperature. The values of m and C0 are compared with those for another die-cast magnesium alloys. The value m=1 is generally detected for die-cast magnesium alloys. On the contrary, the value of C0 sensitively depends on alloy composition, which is reduced with increasing the concentration of alloying elements such as Al, Zn and Ca.

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.

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.

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.

MO-RE 10

Alloy Digest ◽  
1998 ◽  
Vol 47 (10) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Cast Alloy ◽  
Creep Rupture ◽  
Heat Resistant ◽  
Temperature Performance ◽  
Rupture Properties

Abstract MO-RE 10 is a fully austenitic, heat-resistant cast alloy with good creep-rupture properties. Typical applications include pyrolysis and reformer tubing. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on high temperature performance as well as casting. Filing Code: SS-731. Producer or source: Duraloy Technologies Inc.

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