Development and Application of High Cr-High Si-Fe-Ni Alloys to High Efficiency Waste-To-Energy Boilers

2006 ◽  
Vol 522-523 ◽  
pp. 513-522
Author(s):  
Yuuzou Kawahara ◽  
Kouji Sasaki ◽  
Yuuji Nakagawa
Keyword(s):  
Corrosion Resistance ◽  
High Efficiency ◽  
Base Alloy ◽  
Life Time ◽  
Waste To Energy ◽  
Combustion Gas ◽  
Ni Alloys ◽  
Corrosive Environments ◽  
Principal Elements ◽  
Optimum Alloy

In order to improve the durability of high efficiency waste-to-energy boilers, it is essential to develop and apply high temperature corrosion-resistant materials having a long life time according to the intensity of the corrosion conditions. Two types of high Cr-high Si-Fe-Ni base and high Cr-high Si-Ni-Fe base alloy seamless tubes; MAC-N (26Cr-3.5Si-11Fe-Ni base) alloy and MAC-F (23Cr-3.8Si-38Ni-Fe base) alloy respectively which contain no expensive Mo and have better corrosion resistance than the existing alloys under severe corrosive environments of waste combustion gas, have developed. The optimum alloy composition range were defermined by confirming the effect of the alloying elements on the corrosion resistance in the laboratory corrosion tests. Furthermore, the seamless tubes were mounted on the actual superheater of the 500oC/9.8MPa high efficiency waste-to-energy boiler to examine the durability over a period of four years. As a result, it was confirmed that the MAC-N and MAC-F alloys have better corrosion resistance than the Alloy625 and 310HCbN. In addition, it has become clear that corrosion resistance of both alloys is displayed through the formation of SiO2 rich protective scale due to the combined addition of the principal elements, Si, Cr, Fe and Ni. Under conditions of high Cl content molten deposits and severe thermal cycle, the corrosion rate increases as the results of deterioration of protective oxidation scale.

High Temperature Corrosion Resistance of Different Commercial Alloys Under Various Corrosive Environments

2007 ◽  
Author(s):  
Shang-Hsiu Lee ◽  
Marco J. Castaldi
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Metal Surface ◽  
Flue Gas ◽  
Thermal Gradient ◽  
Operating Cost ◽  
High Temperature Corrosion ◽  
Waste To Energy ◽  
Corrosion Rates ◽  
Corrosive Environments

High temperature corrosion is a major operating problem because it results in unscheduled shutdowns in Waste-to-Energy (WTE) plants and accounts for a significant fraction of the total operating cost of WTE plants. Due to the heterogeneous nature of municipal solid waste (MSW) fuel and the presence of aggressive elements such as sulfur and chlorine, WTE plants have higher corrosion rates than coal-fired power plants which operate at higher temperature. To reduce corrosion rates while maximizing the heat recovery efficiency has long been a critical task for WTE operators. Past researchers focused on high temperature corrosion mechanisms and have identified important factors which affect the corrosion rate [1–4]. Also, there have been many laboratory tests seeking to classify the effects of these corrosion factors. However, many tests were performed under isothermal conditions where temperatures of flue gas and metal surface were the same and did not incorporate the synergistic effect of the thermal gradient between environment (flue gas) and metal surface. This paper presents a corrosion resistance test using an apparatus that can maintain a well controlled thermal gradient between the environment and the surface of the metals tested for corrosion resistance. Two commercial substrates (steels SA213-T11 and NSSER-4) were tested under different corrosive environments. The post-test investigation consisted of mass loss measurement of tested coupons, observation of cross-sectional morphology by scanning electron microscopy (SEM), and elemental analysis of corrosion products by energy dispersive spectrometry (EDS). The stainless steel NSSER-4 showed good corrosion resistance within the metal temperature range of 500 °C to 630 °C. The alloy steel SA213-T11 had an acceptable corrosion resistance at metal temperatures up to 540 °C, and the performance decreased dramatically at higher temperatures.

Microstructures of Ti-1.5 w/o Ni Alloys with Mo and A1 Additions

1975 ◽  
Vol 33 ◽  
pp. 54-55
Author(s):  
Anna C. Fraker
Keyword(s):  
Corrosion Resistance ◽  
Beneficial Effect ◽  
Crevice Corrosion ◽  
Local Corrosion ◽  
Precipitate Size ◽  
Ni Alloys

Small amounts of nickel are added to titanium to improve the crevice corrosion resistance but this results in an alloy which has sheet fabrication difficulties and is subject to the formation of large Ti2Ni precipitates. These large precipitates can serve as local corrosion sites; but in a smaller more widely dispersed form, they can have a beneficial effect on crevice corrosion resistance. The purpose of the present work is to show that the addition of a small amount of Mo to the Ti-1.5Ni alloy reduces the Ti2Ni precipitate size and produces a more elongated grained microstructure. It has recently been reported that small additions of Mo to Ti-0.8 to lw/o Ni alloys produce good crevice corrosion resistance and improved fabrication properties.

ALTEMP HX

Alloy Digest ◽  
1993 ◽  
Vol 42 (10) ◽  
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
Nickel Base Alloy ◽  
Temperature Performance ◽  
Nickel Base

Abstract ALTEMP HX is an austenitic nickel-base alloy designed for outstanding oxidation and strength at high temperatures. The alloy is solid-solution strengthened. Applications include uses in the aerospace, heat treatment and petrochemical markets. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, and joining. Filing Code: Ni-442. Producer or source: Allegheny Ludlum Corporation.

CDA C18700

Alloy Digest ◽  
1988 ◽  
Vol 37 (1) ◽  
Keyword(s):  
Electrical Conductivity ◽  
Corrosion Resistance ◽  
Copper Alloy ◽  
Base Alloy ◽  
Heat Treating ◽  
High Electrical Conductivity ◽  
Copper Base ◽  
Screw Machine ◽  
Machine Parts ◽  
Copper Base Alloy

Abstract CDA C18700 is a copper-base alloy containing lead (nominally 1.0%). The lead is added to impart free-cutting properties to the metal. Although the lead lowers the electrical conductivity of CDA C18700 slightly below that of tough-pitch copper, it still has high electrical conductivity well within the limits needed for most current-carrying requirements. Typical uses comprise electrical motor and switch parts, electrical connectors and screw-machine parts requiring high conductivity. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-533. Producer or source: Copper and copper alloy mills.

HAYNES ALLOY No. 36

Alloy Digest ◽  
1959 ◽  
Vol 8 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
Jet Engine ◽  
Temperature Performance ◽  
Cobalt Base Alloy ◽  
Cobalt Base ◽  
Haynes Alloy

Abstract HAYNES Alloy No. 36 is a cobalt-base alloy having excellent strength at temperatures up to 1800 deg. F. It is the cast modification of wrought HAYNES Alloy No. 25 and has been used successfully in jet engine blading and nozzle vanes. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as heat treating, machining, and joining. Filing Code: Co-17. Producer or source: Haynes Stellite Company.

INCONEL ALLOY 722

Alloy Digest ◽  
1965 ◽  
Vol 14 (4) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Base Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Age Hardening ◽  
Nickel Base Alloy ◽  
Inconel Alloy ◽  
Temperature Performance ◽  
Nickel Base

Abstract INCONEL Alloy 722, formerly Inconel W alloy, is a high strength, high-temperature nickel-base alloy responding to age hardening heat treatments for maximum properties. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-100. Producer or source: Huntington Alloy Products Division, An INCO Company.

COLMONOY No. 6

Alloy Digest ◽  
1963 ◽  
Vol 12 (1) ◽  
Keyword(s):  
Compressive Strength ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Base Alloy ◽  
Heat Treating ◽  
Nickel Base Alloy ◽  
High Carbon ◽  
Nickel Base

Abstract Colmonoy No. 6 is a high-carbon, nickel-base alloy recommended for hard facing parts to resist wear, corrosion, heat and galling. This datasheet provides information on composition, physical properties, hardness, elasticity, and compressive strength. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-78. Producer or source: Wall Colmonoy Corporation.

UDIMET 520

Alloy Digest ◽  
1962 ◽  
Vol 11 (9) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Nickel Base Alloy ◽  
Nickel Base

Abstract UDIMET 520 is a nickel-base alloy recommended for applications where high strength at elevated temperatures is required. It is suitable for service at temperatures up to 1800 F. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-74. Producer or source: Special Metals Inc..

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