Wear performance of indexable coated inserts cutting 0Cr17Ni4Cu4Nb stainless steel

Due to the poor processability of 0Cr17Ni4Cu4Nb stainless steel, the inserts are quickly worn down during the cutting process, affecting both the machining accuracy and surface quality of the machined part. In this study, the wear performance of four different types of coated inserts, TiCN+Al2O3, TiAlN, multilayer Ti composite, and TiCN+Al2O3+TiN, were investigated on the external turning of 0Cr17Ni4Cu4Nb stainless steel. The effects of different coatings on insert durability were analyzed from the perspective of wear profile, flank wear, and chip morphology. The wear of the inserts was mainly resulted from abrasive wear, diffusion wear, and adhesive wear. The flank wear ranking from the lowest to the highest for four coated inserts was TiAlN coating, TiCN+Al2O3 coating, TiCN+Al2O3+TiN coating, and multilayer Ti composite coating. The TiAlN coating deposited by physical vapor deposition exhibited excellent high-temperature oxidation resistance and stability, indicating its suitability for the turning of 0Cr17Ni4Cu4Nb stainless steel component. This study provides not only an important guidance for choosing inserts with different coating materials to improve wear performance, but also a good reference on the optimal design of indexable coated inserts for different materials.

NUMERICAL AND EXPERIMENTAL STUDY OF CERAMIC/STEEL COMPOSITE FOR STRUCTURAL APPLICATIONS

The Terminal ballistics is the study of science that deals with the interaction involved in two impacting bodies. This research focused on the high-impact resistance of layered composite comprising of alumina ceramic and armour steel. The composite was designed to have ceramic as the facial plate with armour steel as its backing plate. For the numerical study, the ceramic thickness was varied (6, 8, 10, 12 mm) while keeping the thickness of backing steel constant (7 mm). The projectile, 7.62 mm armour-piercing (AP), was set with a velocity of 838 m/s and made to impact the different ceramic–steel composite target configurations at zero obliquity. The study captured fracture processes of the ceramic, the deformation of projectile, and backing steel. An effective optimum thickness ratio of 1.4 (ceramic:steel; 10/7) for the ceramic/steel components with less deformation of the backing steel is found. Thereafter, the result of the numerical study was validated by experimental ballistic investigation of the determined optimum ceramic/steel ratio. The experiment corroborated the simulation results as the alumina ceramic provided efficient protection to armour steel component after a severe interaction with the impacting projectile.

Multi-exposure X-ray image fusion quality evaluation based on CSF and gradient amplitude similarity

Due to the limitation of dynamic range of the imaging device, the fixed-voltage X-ray images often produce overexposed or underexposed regions. Some structure information of the composite steel component is lost. This problem can be solved by fusing the multi-exposure X-ray images taken by using different voltages in order to produce images with more detailed structures or information. Due to the lack of research on multi-exposure X-ray image fusion technology, there is no evaluation method specially for multi-exposure X-ray image fusion. For the multi-exposure X-ray fusion images obtained by different fusion algorithms may have problems such as the detail loss and structure disorder. To address these problems, this study proposes a new multi-exposure X-ray image fusion quality evaluation method based on contrast sensitivity function (CSF) and gradient amplitude similarity. First, with the idea of information fusion, multiple reference images are fused into a new reference image. Next, the gradient amplitude similarity between the new reference image and the test image is calculated. Then, the whole evaluation value can be obtained by weighting CSF. In the experiments of MEF Database, the SROCC of the proposed algorithm is about 0.8914, and the PLCC is about 0.9287, which shows that the proposed algorithm is more consistent with subjective perception in MEF Database. Thus, this study demonstrates a new objective evaluation method, which generates the results that are consistent with the subjective feelings of human eyes.

Analysis of Computer Modelling Results on Fuel Rods Strength and Condition at Reduced or Absent Cooling Caused by Accident

The paper describes the phenomenology of fuel rod behaviour in severe accident. As an example, an experiment is described resulting in severe damage of 19 fuel rod assembly of VVER type; it was carried out in the CORA facility in 1993 (Research Centre, Karlsruhe, Germany). Testing conditions and results of post-test investigations of fuel assembly are given. The fuel rod code RAPTA-SFD is briefly dealt with; the code was a participant in the International Standard Problem ISP-36. The basic results are presented acquired by computer modelling CORA-W2 experiment using RAPTA-SFD code. Among the presented experimentally acquired and calculated results, the scope of the data on stainless steel component behaviour is substantial. The tested CORA-W2 fuel assembly contained a significant quantity of steel components, viz., spacer grids, a guide thimble, and a cladding of an absorber element. It is to be borne in mind that the spacer grids and a guide thimble of the updated and upgraded fuel assembly of VVER-1000 are fabricated from Zr-alloy, hence, the relative quantitative characteristics of chemical interactions between materials and stainless steel (Cr-Ni alloy) will be much lower for the up-to-date upgraded fuel assembly under identical conditions.

A BIM Platform for the Manufacture of Prefabricated Steel Structure

In the design phase, building information modeling (BIM) software has been widely employed due to its high efficiency, precision, and synergy among different teams. However, the advantages of BIM have not been fully explored in the manufacturing stage where the progress is not so transparent, and information exchange is not so smooth. To deal with these problems, a BIM platform for the manufacture of steel structures is developed in this article, which aims for the management and visualization of manufacturing progress in a steel structure factory in China. The proposed platform was developed and tested by using practical projects. The requirement is analyzed with different users involved in the manufacturing progress. The platform is web-based, where Node.js is adopted for server-side scripting, Neo4j is used for data storage, hyper text markup language (HTML), cascading style sheets (CSS), and JavaScript are used to compile user interface. Besides, a quick response (QR) code is attached to components for traceability. By parsing the BIM model exported in the design phase, essential information of components is imported into the platform, which are the data that form the basis of the following operation. By introducing the platform as a collaborative tool, the traceability and visibility of real-time manufacturing progress of each steel component are significantly enhanced. As a result, this platform can help managers make decisions, workers check quality problems, and other stakeholders grasp the manufacturing progress.