Numerical Simulation and Experimental Investigation of Rotating Blade Centrifugal Jet in Slurry Blast Device Used for Steel Strip Descaling

Under the requirement of clean production, a new type of slurry blast device for mechanically removing oxide scale on the surface of steel strips is presented, which can avoid the serious problems of rapid wear, low service life, and low efficiency of the traditional abrasive water jet with a nozzle. In this paper, the numerical simulation of the rotating blade centrifugal jet in the slurry blast device is conducted based on CFD, where the DPM and the erosion model are innovatively employed to simulate the movement characteristics of abrasive particles and the erosion rate of mixed slurry on the surface of the steel strip. Simulation results show that the erosion rate and particle motion velocity are proportional to the blade rotation speed and inlet pressure. Reasonable inlet pressure and rotation speed are helpful for improving the rust removal efficiency of slurry blast devices. An experimental system is established to validate the simulation results. The experimental results are consistent with the simulation trend, which exhibits that the developed slurry blast device is feasible for steel strip descaling. This work will play substantial guiding roles in the engineering optimization of slurry blast devices for steel strip descaling.

An Experimental Study on the Seismic Performance of High-Strength Composite Shear Walls

In order to study the seismic performance of high-strength concrete composite shear walls with embedded steel strips, four tests for high-strength concrete composite shear walls with embedded steel strips (SPRCW-1 to SPRCW-4) were constructed and tested. Based on the test results, a discussion is provided in the present study on the hysteresis curve, backbone curves, and strain of steel plate and distributed reinforcement of high-strength concrete mid-rise and high-rise composite shear walls with embedded steel strips under different steel ratios and different steel strip positions. The test results reveal that in high-strength composite shear walls with embedded steel strips, the ductility of the test specimen can be effectively improved when the ratio of the steel strip reaches a certain level. In parallel, when the embedded steel strip is placed on both sides of the walls, the steel strip can function better. The ultimate displacement is better than when the steel strip is placed in the middle of the walls, and can effectively improve the seismic performance of the walls. The scheme with embedded steel strips is more convenient and economical for construction, which is suitable for popularization and application in middle-high buildings in highly seismic regions.

Experimental verification referring to the new shape of the perforated steel strip

Perforated steel strips are used as reliable shear connectors many years. During this time, many different shapes of the openings or recesses were developed to improve the durability and resistance of the shear connection. Behaviour of these strips were mainly verified by experimental research, but many parameters could not be measured. Numerical analysis provides not only easy and fast way of testing the behaviour of specimens, but also the possibility to improve the geometry of the strips. Modified steel strips can be deeply investigated in simulations and subsequently verified by push-out tests in laboratories. The combination of these two methods can bring the spectrum of the information that can complexly describe the behaviour, durability and also the weak points of the shear connection, especially in case of the new or modified shape.

Evaluation of the quality of three-layer steel bimetallic strips obtained on a unit of continuous casting and deformation

Today there is an urgency of creating high-performance continuous processes for the production of bimetals. The article describes the main tasks of improving the quality of the materials under consideration. Two stages of the technology for producing steel three-layer bimetallic strips on the unit of a combined continuous casting and deformation process are considered. The authors give recommendations on the conduct of the technological process in order to obtain high-quality bimetallic strips on such unit. The problem statement is presented. The material considers initial data for determining the temperature of the steel base strip and the stress-strain state of the metals of the cladding layers and the strip in deformation center of a three-layer bimetallic ingot. A model for calculating and a method for solving problems of thermal conductivity and elastoplasticity are shown. Regularities of the temperature change of the main steel strip are given during its passage through the molten metal of the cladding layer. Stress-strain state of the metals of the main strip and cladding layers in the deformation center was determined when three-layer bimetallic steel strips were obtained on the unit of combined continuous casting and deformation process. The authors describe the values of compression of the main steel strip and mutual displacement of the layers during compression of the bimetallic ingot by the strikers. Regularities of the distribution of axial and tangential stresses are shown along the contact line of the cladding layer with the striker. The evaluation of the process of obtaining bimetal steel 09G2S - steel 13KhFA - steel 09G2S was made on a pilot unit for continuous casting and deformation. Microstructure of the main strip and cladding layers of a three-layer bimetallic steel strip is shown when a combined continuous casting and deformation process is obtained in one unit.

Analysis of the Reasons for the Tearing of Strips of High-Strength Electrical Steels in Tandem Cold Rolling

High-strength non-oriented electro-technical steels with a low thickness possess excellent isotropy of electromagnetic and mechanical properties which is highly required in the production of high-efficiency electric motors. The manufacturing process of this type of steel includes very important and technologically complex routes such as hot rolling, cold rolling, temper rolling, or final heat treatment. The final thickness is responsible for the decrease in eddy-current losses and is effectively achieved during cold rolling by the tandem rolling mill. Industrial production of thin sheets of high-strength silicon steels in high-speed tandem rolling mills is a rather demanding technological operation due to the increased material brittleness that is mainly caused by the intensive solid solution and deformation strengthening processes, making the dislocation motion more complex. The main objective of this work was to investigate the distribution of local mechanical strains through the thickness of high silicon steel hot bands, generated during the cold rolling. The experimental samples were analysed by means of electron back-scattered diffraction and scanning electron microscopy. From the performed analyses, the correlation between the material workability and the nucleation of cracks causing the observed steel strip failure during the tandem cold rolling was characterized. Specifically, the microstructural, textural, misorientation, and fractographic analyses clearly show that the investigated hot band was characterized by a bimodal distribution of ferrite grains and the formation of intergranular cracks took place only between the grains with recrystallized and deformed structures.

Evidence-Based and Explainable Smart Decision Support for Quality Improvement in Stainless Steel Manufacturing

This article demonstrates the use of data mining methods for evidence-based smart decision support in quality control. The data were collected in a measurement campaign which provided a new and potential quality measurement approach for manufacturing process planning and control. In this study, the machine learning prediction models and Explainable AI methods (XAI) serve as a base for the decision support system for smart manufacturing. The discovered information about the root causes behind the predicted failure can be used to improve the quality, and it also enables the definition of suitable security boundaries for better settings of the production parameters. The user’s need defines the given type of information. The developed method is applied to the monitoring of the surface roughness of the stainless steel strip, but the framework is not application dependent. The modeling analysis reveals that the parameters of the annealing and pickling line (RAP) have the best potential for real-time roughness improvement.

An Impedance Sensor for Distinguishing Multi-Contaminants in Hydraulic Oil of Offshore Machinery

The cleanliness of hydraulic oil can reflect the service life of the oil and the wear state of hydraulic machinery. An impedance sensor is proposed to distinguish multi-contaminants in hydraulic oil. The impedance sensor has two detection modes: the inductance-resistance mode is used to detect metal debris, and the capacitance mode is used to distinguish water droplets and air bubbles. By adding a built-in silicon steel strip and an external silicon steel strip with high magnetic permeability, the distribution area, strength, and uniformity of the magnetic field are enhanced to improve the detection sensitivity under inductance and resistance parameters. In addition, the silicon steel strips are used as electrode plates to introduce capacitance parameter detection. The experimental results show that the resistance detection method based on coil successfully improves the detection ability for non-ferromagnetic metal debris. The impedance sensor for distinguishing multi-contaminants in hydraulic oil can provide technical support for fault diagnosis of offshore hydraulic machinery.