CARTECH 617

CarTech 617 (Pyromet 617) is a corrosion and oxidation-resistant, high-temperature nickel-chromium-cobalt-molybdenum alloy. It is solid-solution strengthened with cobalt and molybdenum. Oxidation resistance is imparted through the addition of chromium and aluminum. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-777. Producer or source: Carpenter Technology Corporation.

Hot Corrosion and Oxidation Behaviour of TiAl Alloys during Fabrication by Laser Powder Bed Additive Manufacturing Process

This research paper summarises the practical relevance of additive manufacturing with particular attention to the latest laser powder bed fusion (L-PBF) technology. L-PBF is a promising processing technique, integrating intelligent and advanced manufacturing systems for aerospace gas turbine components. Some of the added benefits of implementing such technologies compared to traditional processing methods include the freedom to customise high complexity components and rapid prototyping. Titanium aluminide (TiAl) alloys used in harsh environmental settings of turbomachinery, such as low-pressure turbine blades, have gained much interest. TiAl alloys are deemed by researchers as replacement candidates for the heavier Ni-based superalloys due to attractive properties like high strength, creep resistance, excellent resistance to corrosion and wear at elevated temperatures. Several conventional processing technologies such as ingot metallurgy, casting, and solid-state powder sintering can also be utilised to manufacture TiAl alloys employed in high-temperature applications. This chapter focuses on compositional variations, microstructure, and processing of TiAl alloys via L-PBF. Afterward, the hot corrosion aspects of TiAl alloys, including classification, characteristics, mechanisms and preventative measures, are discussed. Oxidation behaviour, kinetics and prevention control measures such as surface and alloy modifications of TiAl alloys at high temperature are assessed. Development trends for improving the hot corrosion and oxidation resistance of TiAl alloys possibly affecting future use of TiAl alloys are identified.

Removal of Dissolved Oxygen from Water by Nitrogen Stripping Coupled with Vacuum Degassing in a Rotor–Stator Reactor

Oxygen is a harmful substance in many processes because it can bring out corrosion and oxidation of food. This study aimed to enhance the removal of dissolved oxygen (DO) from water by employing a novel rotor–stator reactor (RSR). The effectiveness of the nitrogen stripping coupled with vacuum degassing technique for the removal of DO from water in the RSR was investigated. The deoxygenation efficiency (η) and the mass transfer coefficient (KLa) were determined under various operating conditions for the rotational speed, liquid volumetric flow rate, gas volumetric flow rate, and vacuum degree. The nitrogen stripping coupled with vacuum degassing technique achieved values for η and KLa of 97.34% and 0.0882 s−1, respectively, which are much higher than those achieved with the vacuum degassing technique alone (η = 89.95% and KLa = 0.0585 s−1). A correlation to predict the KLa was established and the predicted KLa values were in agreement with the experimental values, with deviations generally within 20%. The results indicate that RSR is a promising deaerator thanks to its intensification of gas–liquid contact.

EFFECT OF HOT CORROSION AND OXIDATION ON COBALT - BASE SUPERALLOYS COATED BY ALUMINUM WITH PRESENCE OF THERMAL BARRIER ZRO2 AND MIXTURE OF (NACL) AND (NA2SO4) STEAMSALTSAT HIGH TEMPERATURES

The aim of the study was to investigate the Mechanisms properties of thermal barrier coatings (TBCs) to enhance of performance evaluation characteristics and develop TBCs.Cobalt –base superalloy has been used as a substrate and zirconium stabilized Aluminum as ceramic topcoat , in addition the study include degradation behavior of system during thermal cycling (3hr per cycle in furnace) the failure of the aluminized was due to thermally grown oxide (TGO) interface. The fractures propagatethrough the interface and produce a deformation of the bond coating . the effect of cycle will result a spallation failure of the TBCsand this is also corresponding to a slightdegradation .The steam of salt (Nacl)and(Na2So4) mixture will affecton the coating lifetimes .The high temperature have a strong effect thermally grown oxide (TGO) which consistent with a first order growth of scale failer variation.

Upgrading Marine Engine Materials for Future Navy Ships

U.S. Navy marine gas turbine engines serve as primarye and auxiliary power sources for several current classes of ships. Early observations noted in the 1960s and 1970s revealed severe corrosion attack on the first stage blade and vane components of a shipboard marine gas turbine engine that caused engine failure after only several hundred hours. In gas turbine development, there is always a drive and need to enhance the performance and life of engines. The virtues of using Ni-base superalloys in hot-section components has been well recognized and practiced as a means of substantial increase in turbine-inlet temperature, resulting in improvements in thermal efficiency, durability, and performance of engines. The USN shipboard environment (the marine environment) is high in salt laden air and water, coupled with air and fuel sulfur species that cause aggressive corrosion in gas turbine hot sections. Materials that can function in this environment are considered to be “Marinized”. Higher engine power density and pressure ratios for new engine designs will increase maximum blade, vane, and rotor metal temperatures from a mainly Low Temperature Hot Corrosion (LTHC) regime into both the High Temperature Hot Corrosion (HTHC) and Oxidation Corrosion regions. It is expected that future increased surface combatant loads and operational changes will require increased gas turbine operating temperatures and change the associated operating environment to one where Type I and Type II hot corrosion AND oxidation will be prevalent in newly anticipated operational profiles. The advanced gas turbine upgrade package will include better corrosion and oxidation resistant capability and/or higher temperature capable materials and their associated component overhaul methodologies. New materials need to be created and developed for use in more aggressive environments and higher temperature operations. The main cause of the shorter time between overhauls is the materials deterioration of the engine components associated with the hot section of the engine, e.g. turbine airfoils. The deterioration mechanisms are hot corrosion, with Type 1 hot corrosion mechanism becoming operative at the higher temperatures. The goal of this paper is to evaluate methods to enable running the engine at high power while getting back to the longer mean time between overhauls. The method to achieve the longer time is to evaluate and propose for implementation materials, which can withstand the higher temperatures and at the same time mitigate the operative corrosion mechanisms associated with marine environments.

Design of self-heating test platform for sulfide corrosion and oxidation based on Fuzzy PID temperature control system

In this paper, the changes of oxidation temperature of sulfide corrosion and the deficiency of distributed optical fiber application were analyzed. The test platform of oxidation temperature of sulfide corrosion was established, and the performance test of optical fiber and the simulation of oxidation temperature of sulfide corrosion were realized. The hardware part of the control system used STM32 as the controller, the software part was based on the process characteristics of the controlled object, using MATLAB to carry out the simulation of PID, fuzzy, fuzzy PD plus I, fuzzy PID algorithms, and their performance are evaluated using both single indexes and comprehensive indexes. The experimental results also showed that the proposed fuzzy PID can achieve better control performance with less overshoot and shorter setting time. Therefore, the fuzzy PID was chosen as the temperature control algorithm to build the optical fiber sensor test platform, and an alarm method for testing the oxidation temperature of large area sulfide corrosion based on the optical fiber performance was obtained. Then, considering the influence of spatial resolution on optical fiber sensor, this paper used piecewise PID to simulate the temperature rise process of three stages of sulfurization corrosion and oxidation. The results showed that the alarm method of oxidation temperature of sulfurization corrosion has limitations for small-scale oxidation of sulfurization corrosion, and it needed to be combined with machine learning to identify temperature anomaly.

Laser Surface Alloying of Austenitic 316L Steel with Boron and Some Metallic Elements: Properties

Austenitic 316L stainless steel is known for its good resistance to corrosion and oxidation. However, under conditions of appreciable mechanical wear, this steel had to demonstrate suitable wear protection. In this study, laser surface alloying with boron and some metallic elements was used in order to improve the hardness and wear behavior of this material. The microstructure was described in the previous paper in detail. The microhardness was measured using Vickers method. The “block-on-ring” technique was used in order to evaluate the wear resistance of laser-alloyed layers, whereas, the potentiodynamic method was applied to evaluate their corrosion behavior. The produced laser-alloyed layers consisted of hard ceramic phases (Fe2B, Cr2B, Ni2B or Ni3B borides) in a soft austenitic matrix. The significant increase in hardness and wear resistance was observed in the case of all the laser-alloyed layers in comparison to the untreated 316L steel. The predominant abrasive wear was accompanied by adhesive and oxidative wear evidenced by shallow grooves, adhesion craters and the presence of oxides. The corrosion resistance of laser-alloyed layers was not considerably diminished. The laser-alloyed layer with boron and nickel was the best in this regard, obtaining nearly the same corrosion behavior as the untreated 316L steel.

The importance of phase composition for corrosion resistance and thermal oxidation behavior of gas-borided layer produced on nickel alloy

Gas boriding was used to produce the borided layer containing a mixture of chromium and nickel borides on the Inconel®600-alloy. The borided sample was characterized by a higher corrosion potential (−0.953 V) than the non-borided sample (−1.005 V). The corrosion current density was significantly lower for the borided sample. The oxidation at 1000 °C for 24 h caused the formation of different oxides on the surface of the borided sample. Simultaneously, the presence of nickel and chromium borides was confirmed by XRD analysis after the oxidation test. It was concluded, that the gas boriding could be an effective barrier against corrosion and oxidation of Inconel®600-alloy.

A perspective on corrosion of multi-principal element alloys

Metallic alloys are critical to essentially all advanced technologies and engineered systems. The well-documented impact of corrosion (and oxidation) of alloys, remains a significant industrial and economic challenge, year on year. Recent activity in the field of metallurgy has revealed a class of metallic alloys, termed multi principal element alloys (MPEAs) that present unique physical properties. Such MPEAs have in many instances also demonstrated a high resistance to corrosion – which may permit the broader use of MPEAs as corrosion resistant alloys (CRAs) in harsh environments. Herein, the progress in MPEA research to date, along with prospects and challenges, are concisely reviewed—with potential future lines of research elaborated.