Effects of hot forging on the structural condition in HS 6-5-2 high-speed steel

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23210%2F19%3A43958050" target="_blank" >RIV/49777513:23210/19:43958050 - isvavai.cz</a>

Result on the web

<a href="https://iopscience.iop.org/article/10.1088/1757-899X/723/1/012002/pdf" target="_blank" >https://iopscience.iop.org/article/10.1088/1757-899X/723/1/012002/pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1757-899X/723/1/012002" target="_blank" >10.1088/1757-899X/723/1/012002</a>

Result language

angličtina

Original language name

Effects of hot forging on the structural condition in HS 6-5-2 high-speed steel

Original language description

Microstructure analysis was performed on rolled bars of high-speed steel after two and three forging cycles, each cycle comprising one upsetting and one drawing out operation. High-speed steels belong to difficult-to-form materials with a narrow forging temperature interval. Forging above the maximum forging temperature may lead to grain coarsening. Below the minimum forging temperature, deformation resistance of the material increases, and the workpiece may fail. Using numerical modelling, special forging dies were designed and effective strain distribution was calculated for an axial cross-section plane in specimens after two and three forging cycles. The purpose of the analysis was to identify the relationship between the amount of effective strain and the shape and size of austenite grain and the volume fraction and density of carbidesafter forging. The size of prior austenite grains was measured using the linear intercept method which is based on the Snyder-Graff method. Grain shapes were characterized in terms of circularity, which is the difference between the shape in question and a circle. With increasing amount of strain, the grains in the materialbecame finer, as undissolved carbides impeded grain growth. In as-received rolled condition, the austenite grain size was G9. After three forging cycles, it was smaller, G11 (the higher the number, the smaller the grains). Circularity characterizes the complexity of a grain shape.Micrographs of carbide particles were taken using a scanning electron microscope and examined with NISElements image analysis software. The majority of carbides were sized between 0.2 and 2μm.The carbides which are less than 1μm in size do not shrink in response to increasing strain and their quantity does not change appreciably. Carbides with a size of 1-2μm show a different behaviour. In the central region of specimens, where strain is the largest, their amounts are much larger than in less-worked regions.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

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OECD FORD branch

20501 - Materials engineering

Project

<a href="/en/project/TH02020161" target="_blank" >TH02020161: Development of high-alloy steel with high metallurgical purity, ultra-fine structure and an enormous degree of forming for special applications</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2019

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

IOP Conference Series: Materials Science and Engineering

ISBN

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ISSN

1757-8981

e-ISSN

1757-899X

Number of pages

9

Pages from-to

1-9

Publisher name

IOP Publishing Ltd

Place of publication

Bristol

Event location

Plzeň

Event date

Sep 10, 2019

Type of event by nationality

EUR - Evropská akce

UT code for WoS article

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