Izdelava programa za izračun faznih deležev ter mehanskih lastnosti jekla v odvisnosti od kemijske sestave in hitrosti ohlajanja

Gošnik, Tin (author), Šarler, Božidar (mentor)

Lastnosti jekla so v veliki meri odvisne od faz in njihovih deležev, ki se tvorijo v jeklu glede na kemijsko sestavo in hitrost ohlajanja. V odvisnosti od teh dveh glavnih vplivnih faktorjev lahko predvidimo fazne deleže, ki bodo prisotni ob koncu procesa ohlajanja. Za namen prikaza deležev faz od sestave in hitrosti ohlajanja smo izdelali računalniški program, napisan v programskem jeziku Python, ki prikazuje ohlajevalno krivuljo ter končne deleže faz v izbranem jeklu in njegove mehanske lastnosti. Program sprejme podatke o CCT diagramih iz programa JMatPro ter podatke o ohlajanju iz lastnega programa za simulacijo ohlajanja jekla na hladilni klopi. Izhodni podatki vsebujejo fazne deleže avstenita, bainita, ferita, martenzita in perlita v jeklu ter pomembne mehanske lastnosti kot so natezna trdnost, meja tečenja in trdota. Za testiranje uporabnosti razvitega računalniškega programa smo izbrali jekla C45, 16MnCrS5 in 42CrMo4 ter čase ohlajanja t85 10 s, 100 s in 1000 s. Eksperimentiranje z različnimi kemijskimi sestavami in hitrostmi ohlajanja je potrdilo zelo različne lastnosti obravnavanih jekel glede na hitrost ohlajanja.

• Language: Slovenian
• Keywords: jeklo, mehanske lastnosti, fazni deleži, kemijska sestava, hitrost ohlajanja, računalniški program
• Work type: Bachelor thesis/paper
• Organization: FS - Faculty of Mechanical Engineering
• Year: 2024
• PID: 20.500.12556/RUL-160861
• Publication date in RUL: 05.09.2024

Secondary language

• Language: English
• Title: Development of a program for calculation of phase fractions and mechanical properties of steel depending on chemical composition and cooling speed

Abstract

The properties of steel depend, to a large extent, on the phases and their fractions that form in the steel according to the chemical composition and the cooling rate. Depending on these two main influencing factors, we can predict the phase fractions that will be present at the end of the cooling process. To display the fractions of phases from the composition and the cooling rate, we developed a computer program written in Python, which shows the cooling curve and the final fractions of phases in the selected steel and its mechanical properties. The program accepts data on CCT diagrams from the JMatPro program and cooling data from our own program for simulating steel cooling on a cooling bench. The output data contains the phase fractions of austenite, bainite, ferrite, martensite, and pearlite in steel and important mechanical properties such as tensile strength, yield strength, and hardness. Test steels C45, 16MnCrS5, and 42CrMo4 and cooling times t85 of 10 s, 100 s and 1000 s were selected to benchmark the utility of the developed computer code. Experimentation with different chemical compositions and cooling rates confirmed very different properties of the considered steels depending on the cooling rate.

• Keywords: steel, mechanical properties, phase fractions, chemical composition, cooling rate, computer code