Prediction of Surface Wrinkle Defect of Welding Wire Steel ER70S-6 in Hot Bar Rolling Process Using Finite Element Method and Experiments

High quality products are demanded due to increasingly fierce market competition. In this paper, the generation of surface wrinkle defect of welding wire steel ER70S-6 was studied by the combination of the experimental method and finite element simulation. Firstly, a thermal compression test was conducted on the Gleeble-3500 thermosimulator under different strain rates and temperatures and a strain dependent Arrhenius-type constitutive function was employed to fit the flow stress–strain curves obtained from the experiments. Then, the elastoplastic constitutive relationship was implemented using radial return mapping algorithm by means of the user subroutine VUMAT of Abaqus/Explicit. A new instability criterion was proposed to predict the possibility of the surface wrinkle defect during the multipass hot bar rolling process. In order to verify the reliability of the finite element model of the six-pass continuous rolling process, the simulated results were compared with experimental data. Finally, the effects of groove width and groove radius on the billet were investigated by the orthogonal test method, and the friction coefficient and rolling temperature. The results show that the groove width and groove radius are key factors to suppress the surface wrinkle defect. Decreasing the groove width can be beneficial for improving the surface quality and reducing the fillet radius. The optimized combination of the rolling process parameters was further applied in an industrial test and the surface quality of the billet was greatly improved.

Study of the Manufacturability of Production and Properties of Welding Wire from Alloy 1580

The results of studies on the production of welding wires with a diameter of 2.5 and 3.3 mm from alloy 1580 are presented. To compare the manufacturability of the processing, various methods were used to obtain billets for drawing with a diameter of 8-12 mm: the traditional method of direct hot extruding (discrete); combined rolling-extruding method; and ingotless rolling-extruding method (continuous). The developed modes of bar rolling, drawing and annealing made it possible to obtain prototypes of wire in laboratory and industrial conditions. It was found that alloy 1580 is highly manufacturable both with the traditional method of pressure treatment (extruding) and with combined rolling-extruding methods. It was revealed that the application of all methods makes it possible to obtain billets with the level of mechanical properties necessary for further multi-operation processing. Based on the results of research obtained in laboratory conditions, rational drawing modes for industrial wire production have been developed. As a result of bay drawing, pilot batches of welding wire with a diameter of 3.26 and 2.47 mm from alloy 1580 were obtained, which was successfully used for welding sheet metal.

Microstructure and properties of 1050A/AZ31 bimetallic bars produced by explosive cladding and subsequent groove rolling process

Within the framework of this study, the 1050A/AZ31 round bimetal bars were produced by the explosive cladding method and subsequent groove rolling process. LM/SEM investigation shown that by proper selection of the explosive cladding parameters (mainly initial distance between 1050A tube and AZ31 core and detonation velocity) it is possible to produce 1050A/AZ31 feedstocks without a continuous layer of Mg–Al intermetallic phases on the interface between joined materials. The experimental tests of the groove rolling process of 1050A/AZ31 bars were supplemented with a theoretical analysis using FEM-based numerical modelling. Based on the test results obtained, it was found that the interface of the 1050A/AZ31 bar rolling at a temperature (300 °C) was characterized by the generation of a thin continuous intermetallic layer without cracks. Applying a higher rolling temperature of 400 °C, which is usually used in hot forming processes of Mg alloys, led to the production of a thicker intermetallic layer, which cracked during the rolling process as a result of deformation. Strength of the fabricated bimetal joints was high, they did not delaminate during shear tests.

Development of Combined Machining Modes, Investigation of Mechanical Properties and Structure of Deformed Semi-Finished Products from Alloy 01417

The article presents the results of studies on the production of wire with a diameter of 0.5 mm from aluminum alloy 01417 with a content of rare-earth metals (REM) in the amount of 7-9% for aircraft construction needs. The deformation modes, the experimental technique and equipment for the implementation of the proposed technology described. The wire was obtained by drawing and bar rolling with subsequent drawing from a rod with a diameter of 5 mm, obtained previously using the process of combined rolling-extruding (CRE) from a continuous ingot with a diameter of 12 mm, cast in an electromagnetic mold (EMM). The wire obtained by the presented technology was subjected to 4 different heat treatment modes with annealing temperatures from 350 to 500 °C and holding time of 1 h in the furnace to achieve mechanical and electrophysical properties corresponding to TS 1-809-1038-2018. The level of strength and plastic properties obtained in the course of research required only one intermediate annealing. The microstructure of the wire was investigated and the modes were revealed that made it possible to obtain the required level of mechanical properties and electrical resistivity, satisfying TS 1-809-1038-2018.

Analysis of Roll Wear Costs During Multi-Strand Rolling of Ribbed Bars Using New Slitting Pass System

The paper presents a modification of the slitting pass system, which ensured a reduction in roll wear during three-strand rolling of ribbed bars with a diameter of 16 mm, and thus reduced the associated costs. The theoretical and experimental research on the rolling process of ribbed bars with a diameter of 16 mm rolled in three-strand technology was carried out on a D350 18-stand continuous bar rolling mill conditions. To determine the cost of slitting pass wear, the results of numerical calculations of the frictional force unit of work obtained using the Forge2011® computer program was used, as well as empirical calculations.

Effect of ECAP on the Microstructure and Mechanical Properties of a Rolled Mg-2Y-0.6Nd-0.6Zr Magnesium Alloy

A fine-grained Mg-2Y-0.6Nd-0.6Zr alloy was processed by bar-rolling and equal-channel angular pressing (ECAP). The effect of ECAP on the microstructure and mechanical properties of rolled Mg-2Y-0.6Nd-0.6Zr alloy was investigated by optical microscopy, scanning electron microscopy, electron backscattered diffraction and a room temperature tensile test. The results show that the Mg-2Y-0.6Nd-0.6Zr alloy obtained high strength and poor plasticity after rolling. As the number of ECAP passes increased, the grain size of the alloy gradually reduced and the texture of the basal plane gradually weakened. The ultimate tensile strength of the alloy first increased and then decreased, the yield strength gradually decreased, and the plasticity continuously increased. After four passes of ECAP, the average grain size decreased from 11.2 µm to 1.87 µm, and the alloy obtained excellent comprehensive mechanical properties. Its strength was slightly reduced compared to the as-rolled alloy, but the plasticity was greatly increased.

THE CONCEPT OF OPTIMAL BAR ROLL PASS DESIGN. REPORT 3. SPACE OF ROLL PASS DESIGN SCHEMES

Based on the system approach and on the experience accumulated at theoretical data, design and industrial development of bar rolling, the Chair “Metal Forming” of Ural Federal University develops the universal “Concept of optimum calibration”. The general ideology of roll pass design optimization is stated in article “The concept of optimal bar roll pass design. Report 1. Basic statements”. In the article “The concept of optimal bar roll pass design. Report 2. Calibers space” the structure, appointment and maintenance of the information block reflecting so-called “calibers space” are considered. According to the general concept of optimization, the following task that needs to be solved is the problem of creation of information block so-called “space of schemes of roll pass design” which will be used further as the first space of optimization. The concept “space of schemes of roll pass design of a bar-rolling mill” is considered as the space containing all possible virtual schemes of rolling of a concrete profile on the concrete rolling mill. For formation of the space of schemes of rail calibrations it is necessary to generate separate virtual schemes and to consistently fill this space with them. Thus, the space of calibrations schemes is formed of separate unique calibrations schemes. For formation of this space from separate calibers, it is offered to use the specialized algorithms which are “generators of schemes of roll pass design”. As an example, the structure of the generator prepared for creation of such space for rolling of railway rails is considered. It is revealed that all known rail calibrations can be presented in the form of essentially the same block structure which is used as the central element of the schemes generator of rail calibrations. Usage of described and similar generators in relation to rolling process of a concrete profile on the concrete rolling mill allows obtaining spaces of acceptable schemes of calibrations. Such spaces are necessary for the subsequent optimizing procedures for search of the best calibration scheme from all possible calibrations. The considered approach for creation of calibrations schemes space can be used during creation of computer-aided engineering systems and optimization of calibrations of rolling rolls.