جستجوی مقالات مرتبط با کلیدواژه « میکروآلیاژ » در نشریات گروه « مکانیک »

Quenching-partitioning heat treatment steels (Q-P) are among the third generation of advanced high strength steels (AHSS) that have been expanded due to having a significant set of mechanical properties including high strength along with appropriate flexibility. The principles of segmentation thermal operations are based on carbon infiltration from martensite to Return austenite (􀀃􀀄) and stabilization of 􀀃􀀄 In the present study, a high strength steel containing Ti microalloy was subjected to Q-P and Q-P-T heat treatment and compared in terms of microstructure and mechanical properties. After quenching-partitioning (Q-P) and quenching-partitioningtempering (Q-P-T) heat treatments were applied to the sheet samples, their properties were determined using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), microhardness measurement. , tensile test and Erickson's test were evaluated. The results showed that the strength and failure strain of Q-P samples were measured as 1062 MPa and 24% and Q-P-T samples as 894 MPa and 27% respectively. Q-P samples showed more strength and less flexibility than Q-P-T samples.

Quenching-partitioning (Q-P) is one of the methods of producing advanced high strength steels (AHSS). The principles of the mentioned thermal process are based on carbon penetration from martensite to residual austenite (γR) and stabilization of γR. In this research, the alloy with the chemical composition of 0.054 wt% Al, 1.5 wt% Si, 2.2 wt% Mn, 2.2 wt% Mn, 0.21 wt% Fe, containing 0.08% Ti as a micro-alloy in an induction melting furnace in VIM was cast as an ingot. The said ingot was homogenized for 3 hours at a temperature of 1200 °C. The homogenized ingot was rolled into a sheet with a thickness of 1.5 mm by hot and cold rolling processes. The prepared sheet was subjected to Q-P heat treatment and direct quenching (D-Q) and was compared in terms of microstructure and mechanical properties. The comparison of the effect of the mentioned operations on the microstructure and mechanical properties of steel was done by scanning electron microscope (SEM), X-ray analysis (XRD), micro-hardness measurement, and metallography. The obtained results showed that the sample subjected to Q-P heat treatment has better formability and strength than the D-Q sample. The strength and formability of the sample obtained from Q-P were reported as 1062 MPa and 24.52% respectively, and the strength and formability of the sample obtained from D-Q were reported as 1484 MPa and 15.21% respectively.

TRIP and Q-P are the main methods to produce advanced high-strength steels (AHSS). These heat treatment methods are based on the penetration of carbon from martensite to retained austenite (γR) and therefore stabilization of γR. In the present study, a high strength steel containing Ti micro-alloy element heat treated by Q-P, TRIP and direct quenching (Q-T) followed by comparison of their microstructure and mechanical properties. The effect of these treatments on the microstructure and mechanical properties of the steel was studied and compared by by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-hardness and metallography. The results showed that the sample performed by Q-P treatment has a good combination of ductility and strength compared to the sample treated by TRIP. The strength and ductility of the Q-P sample were reported to be 1070 MPa and 24%, respectively. The strength and ductility of the sample obtained from TRIP were reported 1160 MPa and 19%, respectively.

Steels with quenching-partitioning (Q-P) heat treatments are the third generation of advanced high strength steels (AHSS) which have been developed due to their interesting combination of mechanical properties including high strength with good flexibility. Partitioning is based on carbon diffusion from martensite (M) to residual austenite (γ_R). In the present investigation, an alloy with a weight composition of % Al 0.054- % Si 1.5 -% Mn 2.2 -% C - 0.21 - Fe containing 0.08% Ti as a micro-alloy was prepared using a vacuum induction melting (VIM) furnace. Purification was performed using an eletro-slag refining (ESR) furnace to reduce sulfur and oxygen and then the molten alloy was cast as an ingot. The ingot was then homogenized at 1200 ° C for 3 hours. The homogenized ingot was then rolled to 1.5 mm thickness sheet by hot and cold rolling processes. After quenching-tempering (Q-T) and quenching-partitioning-tempering (Q-P-T) treatments, the properties of the samples were evaluated by scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), micro-hardness, tensile and Erichsen tests. The Q-P-T samples showed more favorable combination of strength and flexibility in comparison to Q-T samples. The strength and fracture strain of Q-P-T and Q-T samples were 1050 MPa, 24%, and 1185 MPa, 18%, respectively. The Q-P-T samples with remarkably higher strength, showed significantly higher flexibility.