scholarly journals Effects of heat treatment atmosphere on the structure and activity of Pt3Sn nanoparticle electrocatalysts: a characterisation case study

2018 ◽  
Vol 208 ◽  
pp. 555-573 ◽  
Author(s):  
Haoliang Huang ◽  
Abu Bakr Ahmed Amine Nassr ◽  
Verónica Celorrio ◽  
S. F. Rebecca Taylor ◽  
Vinod Kumar Puthiyapura ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Nominal Composition ◽  
Structure And Activity ◽  
Ptsn Catalysts

In this work, a variation in heat treatment atmosphere approach is taken to provide a series of related PtSn catalysts with the same nominal composition of Pt3Sn, but with different surface compositions.

Economic assessment of a 40,000 t/y mixed plastic waste pyrolysis plant using direct heat treatment with molten metal: A case study of a plant located in Belgium

2021 ◽  
Vol 120 ◽  
pp. 698-707
Author(s):  
Frank Riedewald ◽  
Yunus Patel ◽  
Edward Wilson ◽  
Silvia Santos ◽  
Maria Sousa-Gallagher
Keyword(s):  
Heat Treatment ◽  
Molten Metal ◽  
Economic Assessment ◽  
Plastic Waste

Effects of Heat Treatment on Materials Used In Automobiles: A Case Study

2014 ◽  
Vol 11 (5) ◽  
pp. 90-95 ◽  
Author(s):  
Utsav Vatsayan ◽  
◽  
K.M Pandey ◽  
A Biswas
Keyword(s):  
Heat Treatment ◽  
Materials Used

scholarly journals The Experimental Study of the Utilization of Recycling Aggregate from the Demolition of Elements of a Reinforced Concrete Hall

2020 ◽  
Vol 12 (12) ◽  
pp. 5182 ◽  
Author(s):  
Katarzyna Kalinowska-Wichrowska ◽  
David Suescum-Morales
Keyword(s):  
Heat Treatment ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Test Results ◽  
Structural Elements ◽  
Mechanical Recycling ◽  
Control Series ◽  
Coarse Aggregates ◽  
Additional Control

The article shows a case study as to whether the thermal and mechanical recycling of concrete is suitable for concrete debris from the demolition of structural elements of a 30-year-old industrial hall. The experiment included 10 series of new composites made from heated recycled concrete aggregate (HRCA) subjected to different variants of heat treatment and one additional control series with only natural aggregate (NA). The compressive strength of the new concretes has been determined. The microscopic observations of HRCA have also been made. The test results revealed that proper heat treatment of concrete rubble makes it possible to obtain a high-quality recycled coarse aggregate, which can be used as a 100% replacement for natural coarse aggregates in new concretes.

Issues Related to Creep-Strength-Enhanced Ferritic (CSEF) Steels

2014 ◽  
Author(s):  
Rama S. Koripelli ◽  
David N. French
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Case Studies ◽  
Creep Strength ◽  
Pressure Vessels ◽  
Low Alloy Steels ◽  
Allowable Stress ◽  
Pinning Effect ◽  
Superheater Tube

T-91 and P-91 are the oldest of a new class of creep-strength-enhanced ferritic steels (CSEF) approved for use in boilers and pressure vessels. These newer alloys develop high strength through heat treatment, a rapid cooling or quenching to form martensite, followed by a temper to improve ductility. As a result, these alloys offer a much higher allowable stress which means thinner sections provide adequate strength for high-temperature service. Most of the applications thus far have been a substitute for P-22/T-22. The primary advantages of T91 materials over conventional low-alloy steels are: higher allowable stresses for a given temperature, improved oxidation, corrosion, creep and fatigue resistance. T23 is also considered as a member of the family of CSEF steels. The alloying elements such as tungsten, vanadium, boron, titanium and niobium and heat treatment separate this alloy from the well defined T22 steel. Although, T23 is designated for tubing application, its piping counterpart P23 has a strong potential in header applications due to superior strength compared to P22 headers. Now that T-91 and P-91 have been in service for nearly 30 years, some shortcomings have become apparent. A perusal of the allowable stress values for T-91 shows a drop off in tensile strength above about 1150°F. Thus, start-up conditions where superheaters, and especially reheaters, may experience metal temperatures above 1200°F, lead to over-tempering and loss of creep strength. During welding, the temperature varies from above the melting point of the steel to room temperature. The heat-affected zone (HAZ) is defined as the zone next to the fusion line at the edge of the weld metal that has been heated high enough to form austenite, i.e., above the lower critical transformation temperature. On cooling, the austenite transforms to martensite. Next to this region of microstructural transformation, there is an area heated to just below the austenite formation temperature, but above the tempering temperature of the tube/pipe when manufactured. This region has been, in effect, over-tempered by the welding and subsequent post-weld heat treatment (PWHT). Over-tempering softens the tempered martensite with the associated loss of both tensile and creep strength. This region of low strength is subject to failure during service. Creep strength of T91 steel is obtained via a quenching process followed by controlled tempering treatment. Elements such as niobium and vanadium in the steel precipitate at defect sites as carbides; this is known as the ‘pinning effect’. Any subsequent welding/cold working requires a precise PWHT. Inappropriate and/or lack of PWHT can destroy the ‘pinning effect’ resulting in loss of creep strength and premature failures. Several case studies will be presented with the problems associated with T91/T23 materials. Case studies will be presented, with the results of optical microscopy, scanning electron microscopy, hardness measurements and energy dispersive spectroscopy analysis. One case study will discuss how the over-tempering caused a reduced creep strength, resulting in premature creep failure in a finishing superheater tube. A second case presents the carburization of a heat recovery steam generator (HRSG) superheater tube, resulting in reduced corrosion/oxidation resistance. A case study demonstrates how a short-term overheating excursion led to reheat cracking in T23 tubing. Another case will present creep degradation in T91 reheater steel tube due to high temperature exposures (over-tempering).

Influence of Heat Treatment in Air on Thermoelectric Silicon Clathrate

2014 ◽  
Vol 617 ◽  
pp. 243-246 ◽  
Author(s):  
Hiroaki Anno ◽  
Ritsuko Shirataki
Keyword(s):  
Heat Treatment ◽  
Thermoelectric Properties ◽  
Photoelectron Spectroscopy ◽  
Surface Oxidation ◽  
Oxide Phase ◽  
Heat Treatments ◽  
Nominal Composition ◽  
X Ray ◽  
Silicon Clathrate ◽  
Before And After

The influence of heat treatments in air on the surface and thermoelectric properties of polycrystalline silicon clathrate of nominal composition Ba8Al15Si31was investigated. The samples were prepared by combining arc melting and spark plasma sintering methods. Heat treatments were conducted in air at 873 K for 0-480 h. The surface oxidation was investigated by bulk surface X-ray diffraction (XRD) measurements, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The Seebeck coefficient and the electrical conductivity of samples were measured before and after heat treatments. XRD, SEM, EDS, and XPS results revealed that the clathrate phase near the surface was changed to Al-poor clathrate phases and an oxide phase (probably barium aluminate: BaAl2O4). However, the thermoelectric properties of samples were almost unchanged by the heat treatment in air at 873 K for up to 480 h because the chemical composition of the inner part of sample was almost stable.

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