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High Strength, High Temperature Bolting Alloys for Turbine Applications
Published in A Strang, Performance of Bolting Materials in High Temperature Plant Applications, 2020
There have been some significant trends in gas turbine bolting materials over the last several years. Some materials are now less frequently used than they were in the past, as more suitable alloys have become available. For example Alloy 80A is not frequently specified as a bolting material in new applications. Its replacement is usually Alloy 718, which has a higher strength at both room and application temperatures. Jethete M152 has also been displaced because although it is relatively low cost, its maximum operating temperature is quite low, and it suffers from stress corrosion in some environments. FV 535 is a replacement in some applications. Another commonly used material is A286 for temperatures up to about 600°C, but its high expansion coefficient limits its use. Waspaloy is almost the only commonly used alloy for temperatures up to about 700°C. The most widely used engine bolt materials both in the USA and Europe are A286, Alloy 718 and Waspaloy.
Machining of DTC Materials (Stainless Steels and Super Alloys) by Traditional and Non-Traditional Methods
Published in Helmi Youssef, Hassan El-Hofy, Non-Traditional and Advanced Machining Technologies, 2020
The features and specific application of some commonly used Ni-base alloys are given below: Inconel 718 is a recently developed precipitation hardened Ni-base alloy, containing significant amounts of iron, niobium, and molybdenum along with lesser amounts of Al and Ti. It is designed to display exceptionally high yield and creep rupture properties at a temperature up to 700°C. It has excellent weldability as compared to Ni-base alloys hardened by Al and Ti. Application examples include plane engines, nuclear activation furnaces, rocket engines, furnaces, and military warships.Hastelloy X is a solid solution strengthened Ni-base alloy that possesses exceptional strength and oxidation resistance up to 1200°C. It is found to be exceptionally resistant to stress cracking in petrochemical applications. The alloy has excellent forming and welding characteristics. It is recommended especially for use in furnace applications.Nimonic 90 is a precipitation hardened Ni-base alloy of extra-high mechanical properties along with corrosion resistance. It is used in the aerospace industry and as springs operating at high temperatures.René 41 is a high temperature and high strength Ni-base alloy. It possesses good oxidation resistance at high temperatures up to 800°C. It is a useful alloy in gas turbine, aircraft, and marine applications.Waspalloy is a precipitation hardened, Ni-base alloy, which possesses excellent corrosion resistance and is used in elevated temperature applications (900°C), for example gas turbines and aircraft jet equipment.
Combustion Characteristics and Mechanisms of Two Gun Barrel Steels by Promoted Ignition Combustion
Published in Combustion Science and Technology, 2023
Caihong Dou, Cheng Zhang, Congzhen Wang, Junyu Chen, Bin Liang, Jinfeng Huang
At early stage, Benz et al. (1986a) reported the ignition process of Inconel 718, 440A stainless steel, A286 stainless steel, 304 stainless steel, Monel 400 and 440 C stainless steel by different high-velocity particles and proposed that the energy flux density appeared to be one of the major factors governing the ignition process. The group (Benz, Stoltzfus, Benning 1986b) also investigated the flammability of metals and alloys by frictional heating and the presented data do show some major parameters affecting the ignition of materials when exposed to frictional heating. Steinberg et al. (1989) evaluated the relative flammability of nine structural metals (Monel 400, Inconel 600, 316 SS, Waspaloy, Inconel 718, 17–4 PH stainless steel, 440 C stainless steel, 321 stainless steel, Aluminum 2219) in high-pressure oxygen according to four methods. The combustion behavior of several structural metals especially structural steels that served in one condition of high-pressure oxygen, high-speed friction, high-velocity impact of particles have been reported (Hirano et al. 1983; Zawierucha et al. 1987). In some other complex conditions, the flammability and sensitivity of metal parts still need to be considered.
Experimental Investigation on Micro-Electrical Discharge Machining process for heat treated Nickel-based Nimonic 80A
Published in Materials and Manufacturing Processes, 2023
Piyush Pant, Pushpendra S. Bharti
Nickel-based alloys take into account the alloys of nickel possessing high strength, which are suitable for construction purposes as a result of their high strength-to-weight proportion, higher resistance to corrosion and capability to work at greater temperatures. They are largely used in petrochemical, military, aerospace, marine, automotive industries and are mostly usable in sintered, wrought, cast, and forged forms.[1] Alloys that are nickel-based comprise nickel as the major solute and its percentage is more than 50.[2] Nimonic, M252, Udimet, Pyromet-860, M252, Rene, Waspaloy, Haynes 230, and Inconel are some of the nickel-based alloys.[3] Nimonic 80 is the foremost prepared wrought form of nickel-based alloy and it was afterward altered into Nimonic 80A.
Processing of hardened steel by MQL technique using nano cutting fluids
Published in Materials and Manufacturing Processes, 2021
Anshuman Das, Saroj Kumar Patel, Manoranjan Arakha, Abhijit Dey, Bibhuti Bhushan Biswal
Rahman et al.[11] performed the turning operation on titanium alloy using three nanofluids and compared the results with dry and mineral oil-based MQL. Al2O3-enriched vegetable coolant showed the lowest surface roughness compared to other cutting conditions. Better surface texture was also observed with Al2O3-enriched nanofluid. But lowest chip-tool interface temperature and highest chip thickness ratio was obtained with MoS2-enriched cutting fluid. Khajehzadeh et al.[15] analyzed the contact length during hard turning using nanofluids and the results were compared with dry and conventional cooling. The experimental outcomes delineated that by increasing the nanoparticle concentration, nanoparticle size, and cutting speed, the contact length was reduced substantially. Raju et al.[16] conducted the turning operation on En-31 steel in three cutting environments and the results were compared. Nanofluid-based MQL outperformed both dry and conventional oil based MQL in terms of cutting force, tool wear and surface finish. Gajrani et al.[13] conducted the hard machining experiments with different cutting fluids and compared the results in terms of machining forces, tool life, friction, and surface roughness. From the experimental outcomes, it was reported that nanoparticles enriched green cutting fluid performed better than other fluids in terms of all machinability aspects. Their earlier observations[12] reported the similar results while compared the performances of both bio cutting fluid and mineral oil-based cutting fluid with MQL and flood cooling technique during machining of hardened steel. Polvorosa et al.[14] compared the tool wear while machining two super alloys, one is inconel and other is waspaloy with various coolant pressures. The results reported that notch wear was predominant in machining waspaloy compared to inconel 718 but the flank wear was more in case for machining of inconel. The flank wear was diminished during the machining of both alloys in high pressure coolant applications. Material adhesion on tool rake face was more in waspaloy machining compared to inconel 718. Some other studies has also been reported[17181920212223] about the performance of nanofluids using MQL. They analyzed various responses and compared the results with other machining conditions. The inferences indicate that the experimental outcomes of nanofluid machining performed superior against other cutting conditions.