Heat Treatment Of Stainless Steel Research Articles

Effect of powder-pack aluminizing on microstructure and oxidation resistance of wire arc additively manufactured stainless steels

This study investigated the effect of powder-pack aluminizing treatment on the high-temperature oxidation of ER307 stainless steel components fabricated by wire arc additive manufacturing (WAAM) during isothermal oxidation at 1000 °C for 5 h, 25 h, and 50 h. Scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), X-ray diffraction (XRD), X-Ray fluorescence (XRF), nanoindentation testing, and oxidation testing were used to characterize the aluminized and non-aluminized samples produced by WAAM. The results showed that the powder-pack aluminizing increased the surface nano-hardness up to 13.95 GPa and the modulus of elasticity up to 159 GPa, as well as improving the microstructure of WAAM ER307 stainless steel. Indeed, aluminide coatings remained stable up to temperatures exceeding 1000 °C, and the growth of hematite, the main oxide phase, was inhibited by a preferential alumina growth (Al2O3), resulting in an improvement in oxidation resistance in the range of 46–70 %. In addition, owing to the advantages of low-temperature aluminizing, the microstructure, mechanical properties, and oxidation resistance of these alloys have been improved without causing sigma phase formations, which constitute a significant problem in high-temperature heat treatment of stainless steels.

Preface

We would like to introduce you to the Proceedings of the 5th PING Junior conference - Modern Trends in Materials Engineering, which took place from 15 to 17 September 2020 in Pilsen, Czech Republic. The conference is regularly organized by the Regional Institute of Technology (RTI, www.rti.zcu.cz) at the University of West Bohemia.This year’s event was focused mainly on master and doctoral students in order to support their research activities and enable them to present the obtained results. Furthermore, selected research projects were presented within the contributions.This year was very demanding for organizing mass events, and our conference was also affected by the coronavirus epidemic. For this reason, it was organized in a combination of fulltime and online participation.A total of 18 contributions were presented at the conferences, which reflected the research projects solved within RTI. Several presentations were devoted to high-strength steels, such as the optimization of their heat treatment, use for hot stamping technology or their corrosion properties. Other contributions were focused on optimizing the heat treatment of stainless steel. Presentations, which were concentrated on heat or cryogenic treatment of maraging steel in the conventional state and after 3D printing, were also presented. Attention was also paid to special technologies such as semi-solid processing. Of these, six were selected for publication in the proceedings of IOP Conference Series.In conclusion, we would like to invite you to the sixth year of the PING conference, which will take place from 7 to 10 September 2021.List of Scientific Committee, Organizing Committee, Program Committee, Contacts, Images are vilaable in this pdf.

Temperature-dependent evolution of oxide inclusions during heat treatment of stainless steel with yttrium addition

The evolution of oxide inclusions during isothermal heating of 18Cr-8Ni stainless steel with yttrium addition at temperatures of 1273 to 1573 K was investigated systematically. Homogeneous spherical Al-Y-Si(-Mn-Cr) oxide inclusions were observed in as-cast steel. After heating, most of the homogeneous inclusions were transformed into heterogeneous inclusions with Y-rich and Al-rich parts, even though some homogeneous oxide particles were still observed at 1273 and 1573 K. With the increase in heating temperature, more large-sized inclusions were formed. The shape of the inclusions also changed from spherical to irregular. The maximum transformation temperature of inclusions was determined to be 1373 K. The evolution mechanism of inclusions during heating was proposed to be the combined effect of the (i) internal transformation of inclusions due to the crystallization of glassy oxide and (ii) interfacial reaction between inclusions and steel matrix. Meanwhile, the internal transformation of inclusions was considered to be the main factor at heating temperatures less than 1473 K.

Local electrochemical studies after heat treatment of stainless steel: Role of induced metallurgical and surface modifications on pitting triggering

The morphology, the chemical composition, and the pitting corrosion resistance of a resulfurized stainless steel heated at 1000 °C for 2 hours were investigated at the microscale using ex-situ (field-emission-scanning electron microscope/electron dispersion spectrometer (FE-SEM/EDS) and secondary ion mass spectroscopy (SIMS)) and in-situ (electrochemical microcell technique and in-situ atomic force microscope (AFM) techniques. Although microcracks, which may have a deleterious effect, exist, the formation of a compound (Cr,Mn)2(O,S)3 instead of MnS is responsible for the better pitting corrosion resistance of sites containing an inclusion. Local electrochemical measurements indicate that no pitting was detected on these sites below 800 mV/SCE (saturated calomel electrode), whereas stable pitting was observed at around 350 mV/SCE before heating. Micropores were detected on the highly oxidized grains in which the ionic activity was found to be more marked than on the remaining surface (determined using in-situ AFM). Local electrochemical measurements revealed that the presence of such defects reduces significantly the corrosion resistance of the metallic alloy in NaCl-based media.

小特集 ステンレス鋼の表面処理 ステンレス鋼の表面改質のための熱処理

小特集 ステンレス鋼の表面処理 ステンレス鋼の表面改質のための熱処理

Heat treatment of stainless steels in ultra-low vacuum

Treatments were developed (see Tables 4 and 5) for stainless steels used for electrovacuum and electronic instruments, and also an ulta-low vacuum electric furnace.

Heat Treatment of Stainless Steels

Heat Treatment of Stainless Steels

Nitriding of stainless steels with halogen compounds

1. The halogen compounds investigated have no effect on the case depth or the quality of the case on stainless steels. 2. Thermodynamic analysis indicates that halogens used in nitriding and heat treatment of stainless steels shift the thermodynamic potential to the reducing region, as the result of which the atmosphere becomes reducing regardless of the presence of water vapor that oxidizes the steel. 3. Heat treatment of stainless steels in atmospheres with halogens requires that the value of the thermodynamic potential be optimal (above ΔZlim) due to the presence of halogens in the muffle during the process.

Quantitative Comparison of Surface Finishes And Heat Treatment of Stainless Steel With Respect to Corrosion by Jet Fuels★

Abstract Samples were made from free machining AISI 440C stainless steel. They were identically hardened and tempered at 16 different tempering temperatures. The samples were then given five different surface finishes (i.e., grit blast, chro honed, ball burnished, ground and carborundum blast). After initial weighing the samples were subjected to a corrosion environment of JP-4 fuel and water. The samples were removed at varying times, cleaned, and again weighed. Weight losses were compared for different tempering temperatures and different surface finishes. From the test results it was concluded that: (1) This steel should not be heated above 400 C (750 F) for greatest corrosion resistance, (2) Corrosion is greater when no JP-4 fuel is above the water, (3) The order of corrosion resistance was due largely to surface roughness of the different finishes. This order, in decreasing corrosion resistance, is as follows: (a) Ground surface, (b) Ball burnished, (c) Carborundum blast, (d) Chro honed, (e) Grit blast. 6.2.5

ステンレス鋼(SEC15)熔接部の耐蝕性に及ぼす熱処理の影響

The relation between corrosion attack in boiling Strauss' solution and heat treatment of stainless steel (SEC 15) parts was investigated. The results obtained are as follows.(1) In the corrosion tests, having no change of dimension but indicating the differential effect of corrosion due to heat treatment, Strauss' solution as corrosive is superior to HNO3.(2) Though it is the most desirable for corrosion resistivity that solution treatment above 1, 000°C is designed after welding, as-welded or stress relieved condition below 500°C is tolerable, and weldment shall not be treated at temperatures from 600°C to 900°C.(3) In corrosion test by Strauss' solution the line of fusion is more corroded than the heat affected zone, and the welded specimen treated at 700°C is attacked most severely.

The heat-treatment of stainless steel.

Abstract No Abstract Available. Read Nov. 9, 1950 before the Pacific Coast Components of the Edward H. Angle Society of Orthodontia, Del Monte, Calif., and before the Charles H. Tweed Foundation for Orthodontic Research, Tucson, Ariz., April 2, 1951.