Utjecaj uvjeta zagrijavanja i hlađenja na strukturu i mehanička svojstva C-Mn-Si čelika

The paper deals with structure and properties development of AHSS (advance high-strength steel) and UHSS (ultra high-strength steel) steel grades for various groups of automotive parts. C-Mn-Si type steel properties are evaluated based on the results of laboratory controlled rolling and cooling. The important influence on mechanical and plastic properties, amount of residual austenite (RA) and final structural type has, except for cooling rate, also starting temperature of intensive cooling (TIC) which follows after hot plastic deformations. If TIC is from interval of 620-760°C the final structure predominantly consists of ferrite with RA. Mostly acicular ferrite with RA, as well as bainite with RA was obtained when TIC was kept in the range of 760-850°C.Utjecaj uvjeta zagrijavanja i hlađenja na strukturu i mehanička svojstva C-Mn-Si čelika. Članak daje razvitak strukture i svojstava NVČČ (napredno visoko čvrstih čelika) i UVČČ (ultra visoko čvrsti čelici) za raznolike skupine dijelova automobila. Svojstva čelika C-Mn-Si su utvrđena na temelju laboratorijskog kontroliranog valjanja i hlađenja. Najveći utjecaj na mehanička i plastična svojstva uz zaostali austenit (ZA) i završni tip strukture, ima osim brzine hlađenja i početna temperatura intenzivnog hlađenja (Tpo) koja je nastavak vruće plastične deformacije. Ako je Tpo u intervalu 620-760°C, završna struktura se sastoji od ferita sa ZA. Pretežito acikularni ferit sa ZA, također bainit sa ZA je uočen kad je Tpo bila u intervalu 760-850°C

Influence of reheating and cooling conditions on structure and mechanical properties of C-Mn-Si steel

The paper deals with structure and properties development of AHSS (advance high-strength steel) and UHSS (ultra high-strength steel) steel grades for various groups of automotive parts. C-Mn-Si type steel properties are evaluated based on the results of laboratory controlled rolling and cooling. The important influence on mechanical and plastic properties, amount of residual austenite (RA) and final structural type has, except for cooling rate, also starting temperature of intensive cooling (TIC) which follows after hot plastic deformations. If TIC is from interval of 620-760°C the final structure predominantly consists of ferrite with RA. Mostly acicular ferrite with RA, as well as bainite with RA was obtained when TIC was kept in the range of 760-850°C

New directions in ordinal evaluation: Sugeno integrals and beyond

International audienceThis chapter provides a state-of-the-art account of the use of Sugeno integrals in decision evaluation, when it is difficult to use meaningful figures of merit when assessing the worth of a decision and when only a finite scale of, e.g., linguistic categories, can be used. Here, Sugeno integrals are thought of as idempotent lattice polynomial functions on a finite bounded chain, which makes it possible to assign importance weights to groups of criteria or states. Algebraic and behavioral characterizations of the Sugeno integral are presented and discussed, including in the special cases of weighted minima and maxima. Extensions of this framework are also surveyed, namely: the lexicographic refinements that increase the discrimination power of this approach; the use of local utility functions in order to cope with criteria having distinct rating scales; and the generalization of the criteria weighting scheme at work in Sugeno integrals. Another kind of extension considered is when ratings belong to a bipolar scale where good and bad figures are explicitly present, thus giving rise to the symmetric Sugeno integral or to the separate evaluation of pros and cons. Moreover, it is pointed out that Sugeno integrals encode decision rules and that this bridge leads to methods for extractingknowledge from qualitative data. The results of empirical studies of the latter are also presented and discussed, accordingly