W publikacji poruszone zostały kwestie związane z charakterem pękania metali, zdolności absorpcji energii dynamicznej i samohamowania pęknięć. Omówiono podstawy próby udarności metali i stopów sposobem Charpy’ego, z uwzględnieniem różnic w amerykańskim i europejskim wariancie próby. Podkreślono wady i zalety sposobów oceny ciągliwości przełomów udarnościowych opartych na udziale przełomu plastycznego SFA i rozszerzeniu poprzecznym LE. W dalszej części publikacji przedstawiono materiały spawalnicze firmy Metrode przeznaczone do zastosowań kriogenicznych oraz ich właściwości ze szczególnym uwzględnieniem KV i LE w temperaturze –196 stopni Celsjusza.
EN
In the Charpy impact test three key measurements be made – total absorbed energy, Shear Facture Area SFA and Lateral Expansion LE. However, although these three magnitudes have been available from the Charpy test, two of them SFA and LE have been just lately launched in Europe along with new standard EN ISO 148, which combines both American (ASTM E23) and European (EN 10045) regulations. In this paper principles of the impact tests and ductile-brittle fracture characterization are provided as well as comparison between American and European variants of the Charpy impact test. The second part covers specialist and the most demanding area for welding consumables for joining 304L and 316L stainless steel that are subject to service temperatures down to –196 centigrade. The dedicated range of controlled ferrite ‘CF’ consumables manufactured by Metrode is also described and some of the applications for which they been use are highlighted.
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Purpose: In this work, it is pretended to make a comparison of different pearlite contents in pieces with similar shape and dimensions and to analyze the variation of mechanical properties as pearlite content increases. The three pieces used had form of stair made of ductile cast iron. Design/methodology/approach: The present study was based on an adequate balance of alloying elements. None heat treatment was used to obtain different pearlite contents in the microstructures. Many specimens taken from the cast were mechanized to be polished and swabbed with nital to analyze the microstructure. To study the mechanical properties these casts present many tests were done such as Charpy impact test, done at different temperatures. Fracture toughness and tensile strength tests were done, as well. Findings: This study gave evidences that heat treatments are not necessary to obtain different pearlite content in the microstructure. Good mechanical properties are obtained by an appropriate balance of alloying elements. Research limitations/implications: They are that of natural sources. Besides, high and precision technology must be applied to get the present results better. Practical implications: Cast iron productions are focussed straight on machine building and automotive industries and constructions. The low cost production of ductile cast iron, its mechanical properties and low cost transformations are the tempting for application. Originality/value: The whole experimental work and the appropriate results obtained as consequences of the analysis carried out are novel, although applied methods are well known. Values presented in tables are given as new results of our experiments. This work is of great importance for the development of new economical methods for ductile iron production. This study is directed to researchers and metallurgy centres.
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