Yong Zang

A simulation study on the multi-pass rolling bond of 316L/Q345R stainless clad plate

This article describes an investigation into interface bonding research of 316L/Q345R stainless clad plate. A three-dimensional thermal–elastic–plastic model has been established using finite element analysis to model the multi-pass hot rolling process. Results of the model have been compared with those obtained from a rolling experiment of stainless clad plate. The comparisons of temperature and profile of the rolled stainless clad plate have indicated a satisfactory accuracy of finite element analysis simulation. Effects on interface bonding by different parameters including pre-heating temperature, multi-pass thickness reduction rules, rolling speed, covering rate, and different assemble patterns were analyzed systematically. The results show that higher temperature and larger thickness reduction are beneficial to achieve the bonding in vacuum hot rolling process. The critical reduction in the bond at the temperature of 1200 °C is 28%, and the critical thickness reduction reduces by about 2% when the temperature increases by 50 °C during the range from 1000 °C to 1250 °C. And the relationship between the minimum pass number and thickness reduction has been suggested. The results also indicate that large covering rate in the assemble pattern of outer soft and inner hard is beneficial to achieve the bond of stainless clad plate.

Non-linear dynamics of inlet film thickness during unsteady rolling process

The inlet film thickness directly affects film and stress distribution of rolling interfaces. Unsteady factors, such as unsteady back tension, may disturb the inlet film thickness. However, the current models of unsteady inlet film thickness lack unsteady disturbance factors and do not take surface topography into consideration. In this paper, based on the hydrodynamic analysis of inlet zone an unsteady rolling film model which concerns the direction of surface topography is built up. Considering the small fluctuation of inlet angle, absolute reduction, reduction ratio, inlet strip thickness and roll radius as the input variables and the fluctuation of inlet film thickness as the output variable, the non-linear relationship between the input and output is discussed. The discussion results show that there is 180° phase difference between the inlet film thickness and the input variables, such as the fluctuant absolute reduction, the fluctuant reduction ratio and non-uniform inlet strip thickness, but there is no phase difference between unsteady roll radius and the output. The inlet angle, the steady roll radius and the direction of surface topography have significant influence on the fluctuant amplitude of unsteady inlet film thickness. This study proposes an analysis method for unsteady inlet film thickness which takes surface topography and new disturbance factors into consideration.

Comparative Analysis of Bulge Deformation between 2D and 3D Finite Element Models

Bulge deformation of the slab is one of the main factors that affect slab quality in continuous casting. This paper describes an investigation into bulge deformation using ABAQUS to model the solidification process. A three-dimensional finite element analysis model of the slab solidification process has been first established because the bulge deformation is closely related to slab temperature distributions. Based on slab temperature distributions, a three-dimensional thermomechanical coupling model including the slab, the rollers, and the dynamic contact between them has also been constructed and applied to a case study. The thermomechanical coupling model produces outputs such as the rules of bulge deformation. Moreover, the three-dimensional model has been compared with a two-dimensional model to discuss the differences between the two models in calculating the bulge deformation. The results show that the platform zone exists in the wide side of the slab and the bulge deformation is affected strongly by the ratio of width-to-thickness. The indications are also that the difference of the bulge deformation for the two modeling ways is little when the ratio of width-to-thickness is larger than six.

Structure optimization for link suspension system of a 180t BOF vessel

The link suspension system has been used to install a BOF vessel shell in the trunnion ring and has been adopted widely in many steelmaking workshops all over the world. This system is a key component of the oxygen steelmaking process and combines the advantages of well-proven suspension systems with the design philosophy of static determinacy in any operating condition and status of deformation. Recent researches and publications focus on the application of the system and rarely involve in the design mechanics of the system. This paper describes an investigation into the load of link using ADAMS to model the tilting process of BOF. The factors of influencing the link load are also discussed. The indications are that the distribution and parameters of the vertical and the horizontal links have great impact on the laws of loads. An optimization model including these parameters has been constructed to obtain a reasonable load distribution of these links. The optimization results show that vertical links should be assembled vertically and distributed uniformly along circumference of the trunnion ring to reduce theoretically the link loads.

Warping deformation of 316l/q345r stainless composite plate after removal strake

Purpose This study aims to reduce the warping deformation of the stainless composite plate after removal strake by using a finite element method. A three-dimensional thermo-mechanical coupled elastic-plastic finite element model has been suggested by using ABAQUS to simulate the multi-pass hot rolling of stainless composite plate. Design/methodology/approach A three-dimensional thermo-mechanical coupled elastic-plastic finite element model has been suggested by using ABAQUS to simulate the multi-pass hot rolling of stainless composite plate. Warping deformation rules of 316L/Q345R stainless composite plate after removal strake have been analyzed. Moreover, the influences of some different rolling parameters on this deformation have been discussed. Findings The warping deformation just varies in the range of cladding ratio from 0.1 to 0.25. Therefore, cladding ratio does not have a great influence on warping deformation. Originality/value The results show that higher heating temperature, larger final thickness and less rolling passes are beneficial for reducing the warping deformation.

The Analysis of Temperature Field and Residual Stress Distribution during H-Beam Cooling Process

A spot-test of cooling after the finish-rolling was performed for the typical H-beam and the temperature field during the process and residual stress in the beams after the cooling were measured. By using finite element method, the cooling temperature-field of the H700×300 H-beam was simulated and the thermal stress distribution formed in this process was calculated by using thermo-mechanical coupling function. The simulation results matched well with the data obtained on the spot. The accurate description performed in this paper for the temperature field and residual stress distribution of H-beam during cooling process is especially helpful to the manufacture plant. According to the results the reasonable technical parameters can be constituted to control the temperature of the beam in the cooling process and reduce the residual stress in the final product.

Optimal design of mechanism parameters of rolling-cut type cut-to-length shears

Rolling-cut shear is the key equipment of medium plate producing 1ine, while pure rolling shear was set as the target, so that the rolling line is smooth, and the quality of products is improved. This paper describes an investigation into the work Mechanism of rolling-cut shear. A parametric model of rolling-cut shear has been constructed by using ADAMS software. This model was used for two working rolling-cut shear to verify factors influencing quality of products. The influences of the amount of scissors overlapping and shear force are also discussed. The indications are that the length of crank and guard bar, preliminary angle of the crank, the articulated point location of guard bar and frame are key factors to the amount of scissors overlapping and equivalent shear angle. These structure parameters are selected as design variables and the optimization model which was used to reduce scissors overlapping and shear force has been suggested. This optimization model has been employed successfully in the developing of rolling-cut shear 3800 to obtain reasonable mechanism dimensions and improve shearing quality and reduce motor power. The study results provide new idea for developing and optimum design of rolling-cut shear.

Numerical Simulation on the Effect of Process Parameters for Incremental Sheet Forming

Incremental sheet forming (ISF), based on the ‘layered manufacturing’ principle of rapid prototype manufacturing technology, is an innovative and highly flexible technology for forming complex shaped parts without the need for costly dies. This paper presents a numerical investigation on the influence of forming process parameters by modeling the forming process. ANSYS/LS-DYNA has been used for the simulation. The results of study show that small vertical step size can improve the accuracy of the forming. Moreover, large forming angle can increase plastic strain and the four screwdown point optimization paths is an effective method to increase the accuracy of the formed sheet.

Equivalent Tensile Properties Analysis of the Dimpled Sheet

A dimpled sheet is a novel cold-roll structure made from a plain sheet. The yield strength and elastic modulus of the sheet are altered significantly during the dimpling process. In this study, the equivalent tensile properties of a dimpled sheet are examined. First, tensile testing of a dimpled sheet with typical structural parameters is conducted. Then, finite element analysis based on a unit cell is used to analyze the tensile properties; the results are found to be in good agreement with the experimental findings. Finally, the effects of different structural parameters on the equivalent tensile properties of the dimpled sheet are investigated. The results show that the tensile properties can be obtained using the unit-cell finite element method. Further, the changes in the tensile properties are caused by geometric variations and work hardening occurring during the dimpling process. The yield strength of the dimpled sheet first increases and then decreases as the relative thickness increases. However, the yield strength decreases with increasing relative period distance. The equivalent elastic modulus decreases as the relative thickness increases, but increases with the relative period distance. This study and its findings provide theoretical support for optimal design of a dimpled sheet under tensile loading.

Research on the mechanism of spray cooling of H-beam after rolling

In order to reduce temperature difference between the web and flange of the H-beam and in the height direction of the web, the spray cooling technology has been proposed to control the temperature difference when the H-beam left the finishing rolling mill. An experiment of spray cooling for a heated plate has been performed, and this cooling process has been simulated using the computational fluid dynamics software Fluent. The re-normalization group k–ε model has been adopted in this study to simulate turbulence model with discrete phase method. And the temperature fields of the simulated are compared with those of the experiment to verify the correctness of the simulation method. Moreover, a three-dimensional of 1/2 H-beam spray cooling model has also been established. In order to obtain a better cooling effect, the angle between the nozzle center outside the R angle and the inner surface of the flange is defined as 45° and the distance between them is defined as 140 mm. The working pressure of the nozzle, the mean droplet size, and the water flow rate are also suggested to be 0.25 MPa, 150 µm, and 16 L/min, respectively. The recommended nozzle interval in the rolling direction is 300 mm to uniform the temperature distribution along the length direction. The temperature difference between the web and flange of the H-beam and the temperature difference in the height direction are decreased 234°C and 71.8°C, respectively.