Studies on Susceptibility of Alloy 617 to Solidification Cracking

2019 ◽  
Vol 969 ◽  
pp. 34-40
Author(s):  
R. Ravibharath ◽  
K. Devakumaran ◽  
V. Muthupandi
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Hot Cracking ◽  
Solidification Cracking ◽  
High Temperature Strength ◽  
Test Results ◽  
Alloy 617 ◽  
Creep Properties ◽  
Varestraint Test ◽  
Super Alloy

Ni based super alloy 617 is widely used in transition liners in both aircraft and land-based gas turbines, power plant applications because of its high temperature strength, oxidation resistance and creep properties. Ni based alloys are highly susceptible to hot cracking like solidification and liquation racking issues. In this present work, the susceptibility of alloy 617 to solidification cracking is studied based on the varestraint test. Results of this weldability test proved that in addition to the solidification cracking susceptibility alloy 617 is prone to liquation cracking also. Keywords: Varestraint test, Alloy 617, Solidification cracking, Liquidation cracking.

Hot Cracking Susceptibility in Duplex Stainless Steel Welds

2018 ◽  
Vol 941 ◽  
pp. 679-685
Author(s):  
Kazuyoshi Saida ◽  
Tomo Ogura
Keyword(s):  
Stainless Steels ◽  
Laser Beam Welding ◽  
Austenitic Stainless Steels ◽  
Hot Cracking ◽  
Duplex Stainless Steels ◽  
Solidification Cracking ◽  
Solidification Mode ◽  
Gas Tungsten Arc ◽  
Varestraint Test ◽  
Super Duplex Stainless Steels

The hot cracking (solidification cracking) susceptibility in the weld metals of duplex stainless steels were quantitatively evaluated by Transverse-Varestraint test with gas tungsten arc welding (GTAW) and laser beam welding (LBW). Three kinds of duplex stainless steels (lean, standard and super duplex stainless steels) were used for evaluation. The solidification brittle temperature ranges (BTR) of duplex stainless steels were 58K, 60K and 76K for standard, lean and super duplex stainless steels, respectively, and were comparable to those of austenitic stainless steels with FA solidification mode. The BTRs in LBW were 10-15K lower than those in GTAW for any steels. In order to clarify the governing factors of solidification cracking in duplex stainless steels, the solidification segregation behaviours of alloying and impurity elements were numerically analysed during GTAW and LBW. Although the harmful elements to solidification cracking such as P, S and C were segregated in the residual liquid phase in any joints, the solidification segregation of P, S and C in LBW was inhibited compared with GTAW due to the rapid cooling rate in LBW. It followed that the decreased solidification cracking susceptibility of duplex stainless steels in LBW would be mainly attributed to the suppression of solidification segregation of P, S and C.

Research on Effect of Alloy Elements on Equilibrium and Properties of Ni-Cr-Co Type Nickel-Based Superalloy

2016 ◽  
Vol 849 ◽  
pp. 513-519
Author(s):  
Qing Quan Zhang ◽  
Ming Yang Li ◽  
Ran Wei ◽  
Hui Yun Wu ◽  
Zhen Rui Li
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Nickel Based Superalloy ◽  
Type 3 ◽  
Room Temperature Strength ◽  
Super Alloy ◽  
Type Nickel

Ni-Cr-Co type Nickel-based super alloy Inconel 740H was studied. The effect of Nb, Al and Ti on the equilibrium of this alloy was analyzed by JMatPro software. The amount of Ti and Nb should be controlled by 1.50wt.%, and meanwhile, Al should be 1.0-2.0wt.%. If Mo and W were added the amount of Mo should be in the range of 1.0-2.0wt. %, and W should be about 1.0wt.%. Based on these results, three types of new alloys were designed, which contain Ni-Cr-Co-Mo type (1#), Ni-Cr-Co-W type (2#) and Ni-Cr-Co-Mo-W type (3#). Compared with the Ni-Cr-Co type Inconel 740H alloy, the room temperature strength, high temperature strength and high temperature durable performance of the three new alloys improved, which can provide the evidence and reference to optimize the chemical composition of Inconel 740H alloy, i.e., adding 1.50wt.% Mo and 1.0wt.% W individually or together.

Development of a New Hot Gas Double Axial Valve and Design Concept for a Coaxial Valve

1986 ◽  
Author(s):  
J. Kruschik
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Chemical Plants ◽  
Test Results ◽  
Closed Cycle ◽  
Secondary Circuit ◽  
Hot Gas ◽  
Nuclear Plants ◽  
New Generation ◽  
Prototype Design

The hot gas double axial valve is a newly developed shut-off valve for high temperature and high pressure helium, which can be used in the new generation of helium cooled nuclear plants, including the modular reactor. It is the safety shut-off valve in the secondary circuit after the heat-exchanger. At first it will be used in the German project PNP (nuclear process heat for the gasification of coal), but it can also be used for the other high temperature systems such as the closed cycle nuclear gas turbine, chemical plants or for industrial processes. Its state of development, test results, and the present prototype design are discussed. A further concept for a coaxial valve will be shown, which may be of interest for certain types of modular reactors and also for closed cycle nuclear gas turbines.

Evaluation of Additives for Prevention of High Temperature Corrosion of Superalloys in Gas Turbines

1973 ◽  
Vol 95 (4) ◽  
pp. 333-339 ◽  
Author(s):  
S. Y. Lee ◽  
W. E. Young ◽  
G. Vermes
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Screening Tests ◽  
Test Results ◽  
X Ray Diffraction ◽  
Chemical Additives ◽  
X Ray ◽  
Contaminant Level ◽  
Made In

A number of commercially available chemical additives for utilization in modern high temperature gas turbines were evaluated for their corrosion and deposit inhibiting characteristics. The evaluation was made in pressurized passages which simulate conditions of operating gas turbines. Initial screening tests of 10 hr each were made with a contaminant level of 50 ppm vanadium, and promising additives were further tested for times up to 300 hr at the more realistic contaminant level of a No. 3 GT fuel. Characteristics of the deposits were studied with x-ray diffraction and ash fusion tests. Corrosion rates for various alloys tested with treated fuel were measured and compared to test results obtained with untreated fuel. Conclusions were drawn as to the type of elements most effective in reducing corrosion caused by combinations of vanadium and sodium. The role of elements in preventing deposit buildup is also assessed.

Effect of Zr Addition on High Temperature Mechanical Properties of Near Alpha Ti-Al-Zr-Sn Based Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 580-583 ◽  
Author(s):  
Murugesan Jayaprakash ◽  
De Hai Ping ◽  
Y. Yamabe-Mitarai
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Test Results ◽  
High Temperature Mechanical Properties ◽  
Ti Alloys ◽  
Zr Addition ◽  
And Performance ◽  
Compressive Tests

Titanium (Ti) alloys are widely used in aerospace industries successfully up to 600°C. Increasing the operating temperature and performance of these alloys would be very useful for fuel economy. Numerous numbers of research works has been focused on the improvement of the high temperature performances of Ti alloys. It has been well known that Zirconium (Zr) is one of the important solid-solution strengthener in Ti-alloys. In the present study, the effect of Zr addition on the microstructure and mechanical properties of the near–α Ti-Al-Zr-Sn based alloys has been investigated.The compression test results showed that Zr addition significantly improves both room temperature and high temperature strength. The results obtained were explained based on the microstructural observation, room temperature and high temperature compressive tests.

Creep-Environment Interactions of Alloy 617 at Elevated Temperature

2008 ◽  
Author(s):  
Daejong Kim ◽  
Changheui Jang ◽  
Woo Seog Ryu
Keyword(s):  
High Temperature ◽  
Creep Strain ◽  
Elevated Temperatures ◽  
Extended Period ◽  
Nickel Base Superalloy ◽  
Environment Interaction ◽  
Creep Tests ◽  
Alloy 617 ◽  
Creep Properties ◽  
Deformation Properties

Creep behavior and degradation of creep properties of high-temperature materials often limit the lives of components and structures designed to operate for extended period under stress at elevated temperatures. A nickel-base superalloy, Alloy 617 in particular which is considered as a prospective material for hot gas duct and intermediate heat exchanger in very high temperature gas cooled reactor, was studied for creep properties. Creep tests were carried out under various sustained tensile loadings in air and helium environments at temperature of 800°C, 900°C, and 1000°C. Times for 1% creep strain and creep rupture were taken from the short-term creep tests within 1000 hours. Effect of creep-environment interaction on creep strain and changes in viscous deformation properties by dynamic recrystallization were discussed.

scholarly journals Characterisation of microstructure and creep properties of alloy 617 for high-temperature applications

2014 ◽  
Vol 619 ◽  
pp. 77-86 ◽  
Author(s):  
S.F. Di Martino ◽  
R.G. Faulkner ◽  
S.C. Hogg ◽  
S. Vujic ◽  
O. Tassa
Keyword(s):  
High Temperature ◽  
Alloy 617 ◽  
Creep Properties ◽  
Temperature Applications

Degradation Characteristics of Inconel738LC with Thermal Exposure

2011 ◽  
Vol 275 ◽  
pp. 117-120
Author(s):  
Keun Bong Yoo ◽  
Han Sang Lee ◽  
Kyu So Song
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Stress Rupture ◽  
Thermal Exposure ◽  
High Temperature Strength ◽  
Material Degradation ◽  
Temperature Dependent ◽  
Microstructural Investigation ◽  
Combustion Gas ◽  
Hot Gas

Gas turbine components operated by hot combustion gas undergo material degradation due to the thermal cycle by daily startup and shutdown. The failure mechanism of the hot gas components is accompanied by degradation in the properties of high temperature strength and creep rupture time. Many hot gas components in gas turbines are made of Ni-based superalloy because of their high temperature performance. In this work, we survey the time and temperature dependent degradation of Ni-based superalloy. We prepared specimens from Inconel738LC that were then exposed at 871~982°C in 1,000~5,000hours. We carried out stress-rupture tests and microstructural investigation.

High Pressure Test Results of a Catalytic Combustor for Gas Turbine

1998 ◽  
Vol 120 (3) ◽  
pp. 509-513 ◽  
Author(s):  
T. Fujii ◽  
Y. Ozawa ◽  
S. Kikumoto ◽  
M. Sato ◽  
Y. Yuasa ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Catalytic Combustion ◽  
Combustion Process ◽  
Combined Cycle ◽  
Nox Emission ◽  
Test Results ◽  
Catalytic Combustor

Recently, the use of gas turbine systems, such as combined cycle and cogeneration systems, has gradually increased in the world. But even when a clean fuel such as LNG (liquefied natural gas) is used, thermal NOx is generated in the high temperature gas turbine combustion process. The NOx emission from gas turbines is controlled through selective catalytic reduction processes (SCR) in the Japanese electric industry. If catalytic combustion could be applied to the combustor of the gas turbine, it is expected to lower NOx emission more economically. Under such high temperature and high pressure conditions, as in the gas turbine, however, the durability of the catalyst is still insufficient. So it prevents the realization of a high temperature catalytic combustor. To overcome this difficulty, a catalytic combustor combined with premixed combustion for a 1300°C class gas turbine was developed. In this method, catalyst temperature is kept below 1000°C, and a lean premixed gas is injected into the catalytic combustion gas. As a result, the load on the catalyst is reduced and it is possible to prevent the catalyst deactivation. After a preliminary atmospheric test, the design of the combustort was modified and a high pressure combustion test was conducted. As a result, it was confirmed that NOx emission was below 10 ppm (at 16 percent O2) at a combustor outlet gas temperature of 1300°C and that the combustion efficiency was almost 100 percent. This paper presents the design features and test results of the combustor.

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