检索结果-南通市图书馆

Prediction of Austenitization and Homogenization of Q235 Plain Carbon Steel during Reheating Process

在线全文

学校读者我要写书评

暂无评论

引用

Journal of Materials Science & Technology 2002年第1期18卷 39-42页

作者： ChunliMO dianzhongli 等 ShenyangInstutiteofTechnology Shenyang110015China InstituteofMetalResearch ChineseAcademyofSciencesShengyang110016China

In this paper, the austenitization and homogenization process of Q235 plain carbon steel during reheating is predicted using a two-dimensional model which has been developed for the prediction of diffusive phase transformation (e.g. α to γ). The diffusion equations are solved within each phase (α and γ) and an explicit finite volume technique formulated for a regular hexagonal grid are used. The discrete interface is represented by special volume elements α/γ, an volume element a undergoes a transition to an interface state before it becomes γ. The procedure allows us to handle the displacement of the interface while respecting the flux condition at the interface. The simulated microstructure shows the dissolution of ferrite particles in the austenite matrix is presented at different stages of the phase transformation. Specifically, the influence of the microstructure scale and the heating rate on the phase transformation kinetics has been investigated. The experimental results agree well with the simulated ones.

关键词： Austenitization Phase transformation Finite volume technique Microstructure Homogenization

Modelling of Microstructural Evolution and Prediction of Mechanical Properties of Plain Carbon Strip Steel in Hot Rolling Process

在线全文

学校读者我要写书评

暂无评论

引用

Journal of Materials Science & Technology 2004年第5期20卷 501-505页

作者： XiaochunSHA ChunliMO dianzhongli YiyiLI InstituteofMetalResearch ChineseAcademyofSciencesShenyang110016China ShenyangInstituteofTechnology Shenyang110168China

Based on hot rolling production line of strip steel, the off-line in-house software, termed as ROLLAN (Rolling Analysis), is developed. The code is mainly used to predict the evolution of temperature, rolling force, fraction and grain size of recrystallization, fraction and grain size of phase transformation and final mechanical properties. Almost all the processing parameters affecting microstructure and mechanical properties in the schedule from reheating to the coiling process are considered in detail. Self-learning coefficient is adopted to adjust the deviation between predicted and measured temperatures, such as roughing exit temperature (RT2), finishing exit temperature (FT7) and coiling temperature (CT). Due to the application of low-speed-threading, increasing-speed-rolling and decreasing-speed-delivery process during finishing rolling and different cooling condition, after coiling the thermal-mechanical history of different position, along strip longitudinal direction is different resulting in inhomogeneous mechanical properties. So the segments are divided along longitudinal direction to identify the variation of microstructure and mechanical properties. An example of plain carbon strip steel Q235 with various thickness is used to compare the calculated mechanical properties with measured ones. For the specific grade of Q235 , the maximum deviation of tensile strength is less than 10.3 MPa, the yield strength is less than 13.2 MPa, and elongation is less than 1.99%. Further work will focus on the on-line application and consider the effect of macrosegregation and sulfur content of cast slab.

关键词： Microstructural evolution Hot rolling Mechanical properties Modeling

Modelling of Phase Transformation of Plain Carbon Steels during Continuous Cooling

在线全文

学校读者我要写书评

暂无评论

引用

Journal of Materials Science & Technology 2003年第3期19卷 262-264页

作者： YutuoZHANG ChunliMO dianzhongli YiyiLI InstituteofMetalResearch ChineseAcademyofSciencesShenyang110016China ShenyangInstituteofTechnology Shenyang110016China

A model based on Avrami equation and Scheil's additivity rule was proposed to simulate the phase transformation in plain carbon steels during continuous cooling in hot strip mill. In this model, a wide range of composition, cooling rate, primary austenite grain size and retained strain has been taken into account. It can be used to calculate the phase fraction transformed at different temperatures during continuous cooling. The phase equilibrium and transformation starting temperature can be determined by using Thermo-Calc and DICTRA. The simulated results containing the transformation at starting and finishing temperatures, Ae1, Ae3 and the maximum volume fraction for Q235B, were obtained. The calculated phase volume fractions are in good agreement with .the experimental results.

关键词： Phase transformation Continuous cooling Plain carbon steels