Modification of the contents of alloying elements with a narrower interval of Cr, Ni and Al can be obtained austenitic-martensitic steel 17-7PH which by, a subsequent heat treatment, can have values of mechanical and chemical properties required for components of automotive engine. Studies have confirmed that the rod dimensions 16mm made of steel 17-7PH with modified content of chromium, nickel and aluminum in combination with heat treatment solution annealing and precipitation hardening, gave values of mechanical properties, satisfying the requirements for steel with standard chemical composition.After aging was obtained martensitic austenitic microstru-cture, with a high percentage of martensite with a slight presence of delta ferrite.

<p>The demand for stainless steels has been steadily increasing across industries such as automotive,<br />aerospace, aviation, medical technology, and household appliances, primarily due to their excellent<br />corrosion resistance, low thermal conductivity, and favorable strength-to-weight ratio. Many of<br />these applications involve components with complex geometries and strict dimensional<br />tolerances, making machinability a crucial factor.<br />Technical surfaces are not ideally smooth geometric surfaces separating two media, but are, from<br />a microscopic point of view, rough surfaces characterized by a series of irregularities of different<br />sizes, shapes, and arrangements. The roughness represents the microgeometric irregularities of the<br />surface, i.e., unevenness at the small reference length (l) of a given direction of the surface.<br />According to the available literature, the effect of alloying elements on roughness during<br />conventional turning has not been sufficiently investigated. Therefore, the objective of this study<br />is to investigate and quantify the effect of alloying elements and nonmetallic inclusions on<br />roughness magnitudes in the longitudinal turning process of X8CrNiS18-9 stainless steel.</p>

Material properties are crucial factors in the modern world, influencing products quality, functionality and overall durability. Knowledge of these critical mechanical properties of materials used in a vast array of industrial and consumer products, transportation, construction, healthcare, and advanced manufacturing is essential to preventing health and safety hazards, controlling the costs of production and creating better-designed, more durable and higher quality products. Hardness is an extremely important material property describing a material’s resistance to localized deformation from an indenter pressing or scraping against its surface. It is determined by measuring the indentation size realised on the tested material surface. This can be done by different hardness testing methods, like the Brinell, Vickers and Knoop (BVK) scales. Hardness is not a physical quantity; it is a method-based quantity and thus the definition of the method and the measurands subject to consideration in hardness are very critical. The uniform use and recognition of such methods require the establishment of accurate, reliable and consistent reference standards at the NMI level and a link to end-user measurements for the lowest level tests in workshops, guaranteeing a continuous traceability chain. However, hardness measurement results are frequently inconsistent with the nominal values of the blocks, highlighting the lack of detailed, standardised measurement methodology and instrumentation, although all instruments used are compliant with relevant ISO hardness standards from a length measurement point of view. This can be attributed to a lack of a commonly accepted definition of the measurand (indentation) and uniformity in the methodology used, as well as a lack of traceability between NMIs and from the NMI level to the end user. The project 22RPT01 TracInd BVK-H addresses these challenges by establishing a unified, traceable, and scientifically robust framework for BVK hardness testing. The proposed solution to the problem of inconsistent hardness measurements consists of defining universally agreed-upon definitions for indentation boundaries and measurement conditions, therefore providing a consistent starting point for the propagation down the traceability chain. Building on this, new long-term stable and high-quality reference indentations to be used as transfer standards are being developed. The proposed set of reference indentations will ensure the traceability of real indentation measurements in three dimensions rather than two dimensions as is currently possible, eliminating errors caused by the varying imaging systems and magnifications in use. This is accompanied by the development of advanced uncertainty models for BVK hardness tests, a methodology to ensure traceable measurements from primary standards to the end-user, and automation of hardness measurements in order to address challenges associated with operator subjectivity and significantly enhance reproducibility. The consortium, consisting of leading NMIs, universities and manufacturers, will disseminate the project’s findings to international metrology and standardization organizations, including the CIPM and ISO. Recommendations for next-generation hardness instruments will guide manufacturers, resulting in instruments producing more consistent results and therefore significant advance hardness metrology at all traceability levels. By addressing longstanding inconsistencies in hardness testing, this project is enhancing the scientific rigor of hardness metrology and enabling more reliable uniform testing on a global scale.

<p style="text-align: justify;">This paper describes the difference in the creep rate of pre-strained and no pre-strained samples of superalloy N07080. The primary strengthening mechanism of this superalloy is based on the precipitation of fine and coherent particles of the intermetallic &gamma;' phase Ni₃(Al,Ti) that ensure good creep resistance. In the case of additional strengthening of superalloy N07080 by warm plastic deformation, sometimes required by the automotive industry, its life in creep conditions will be significantly reduced. Performing the partial recrystallization annealing, after solution annealing and warm deformation, and before the final precipitation annealing, leads to a decrease in strength and an increase in the superalloy ductile properties and return of part of the lost creep life due to warm deformation.</p> <p style="text-align: justify;">Because of the shorter lifetime of warm-deformed superalloy N07080 samples, their creep rate is higher than that of those not warm-deformed. The creep rate at 50 % of creep rupture life of superalloy N07080 that warm rolled by 30% deformation (1080&deg;C/8h+30% warm def.+700&deg;C/16h) is 12,9 times higher than the creep rate of the standard heat-treated superalloy. This creep rate reduces with increasing partial recrystallization temperature and for recrystallization temperature 1080&deg;C it reaches values close to those that the superalloy possesses after standard heat treatment (1080&deg;C/8h+700&deg;C/16h).</p>

<p>Steel 17-7PH is austenitic-martensitic steel with high strength, hardness, and resistance to creep, and<br />corrosion. It is designed for aerospace components, but can also be used for other applications that require<br />high strength and corrosion resistance, as well as leaf springs for operation at temperatures up to 316 &deg;C. It<br />can be used in a solution-treated or heat-treated state to obtain a wide range of property values. This<br />paperwork shows that modification of the contents of alloying elements with a narrower interval of Cr, Ni,<br />and Al can be obtained from austenitic-martensitic steel 17-7PH which by, a subsequent heat treatment,<br />can have values of mechanical and chemical properties required for components of an automotive engine.<br />Chromium is an alphagenic alloying element that stabilizes the ferrite region, nickel is a gammagenic<br />alloying element that stabilizes austenite and gives these steels good strength and toughness, even at low<br />temperatures and aluminum increases corrosion resistance in low-carbon corrosion-resistant steels<br />Research has determined the most suitable interval of Cr, Ni, and Al, which in combination with the<br />cryogenic heat treatment RH950 at -50 &deg;C gives the mechanical and chemical properties that meet the<br />requirements for steel with standard chemical composition.</p>

<p>More recently modified stainless steels have been used to produce various structural elements that work in complex operating conditions. Stainless steel X8CrNiS18-9 (standard EN 10088-3) is the most commonly used from the group of austenitic stainless steel in terms of machinability. This steel has high mechanical and working properties thanks to a complex alloying, primarily with elements such as chromium and nickel. The content of sulphur present in the steel from 0.15 to 0.35% improves machinability. However, sulphur at the same time decreases the mechanical properties, particularly toughness. In steel, tellurium stabilizes carbides and reduces the microporosity of the structure. Also, tellurium is now recognized as a powerful sulphur modifier as well as a machinability additive when used in combination with lead and sulphur. This work aims to determine the influence of tellurium on the machinability, corrosion resistance and mechanical properties of the mentioned steel.</p>

Additional strengthening of superalloy N07080 described in this work was achieved by warm rolling. Control of the ratio of strength and ductile properties of the superalloy is possible by appropriate selection of the amount of warm deformation and the appropriate selection of the partial recrystallization temperature. In addition, recrystallization annealing makes it possible to equalize the grain size across the cross section of the warm rolled bars, which before recrystallization differ significantly in size in the central and peripheral parts of the bars.

Magnesium based materials are considered promising biodegradable metals for orthopedic bone implant applications as they exhibit similar density and elastic modulus to that of bone, biodegradability, and excellent osteogenic properties. The use of Mg based biomaterials eliminates the limitations of currently used implant materials such as stress shielding and the need for the second surgery. Recently, the development of Mg-based implants has attracted significant attention. Additive manufacturing is one of the effective techniques to develop Mg based implants. Additive manufacturing which could be named 3D printing is a transformative and rapid method of producing industrial parts with in the acceptable dimensional range. Therefore, recent investigations have tried to apply this method for the development of Mg-based implants. This state-of-the-art review focuses on the additive manufacturing of Mg biodegradable materials and their in-vitro corrosion and degradation, and mechanical properties. The future directions to develop Mg biodegradable materials are reported through summarization of current achievements.