The Evaluation Effect of the Active Lubricating Coating on the Mechanical Properties of Stamped Semi-Finished Products Made of Refractory Metals

We investigated the possibility of using an organofluorine coating on parts of the "Screen" type made by cold stamping from refractory metals, in particular niobium. The paper also presents the results of a study of the mechanical characteristics of samples with acoustic-emission accompaniment and the hardness values before and after applying the organofluorine composition. The surface of parts with and without coating after convolution is studied. It is shown that it is possible to prevent loss of stability during the first operation of the technological process, as well as to reduce the number of operations by eliminating annealing between subsequent operations of drawing with thinning.

Reducing the flaws of 08Yu steel sheet blanks, designed for cold stamping products

The aim of the work is to develop a method of increasing the technological plasticity while maintaining the strength and preventing aging of blanks of cold-rolled sheet steel 08Yu. The task of this work is research and determination of optimal temperature-time parameters of high-speed contact recrystallization annealing and subsequent aging of 08Yu steel sheet blanks to obtain the required level of mechanical properties that would improve their deformability and ability of very deep drawing during cold stamping of products. The optimal parameters of the speed mode are set recrystallization annealing of cold-rolled 08Yu sheet steel, which provides the best structure and properties for further cold pressure treatment. The temperature-time modes of further aging and possibilities to prevent the processes of its natural aging during prolonged operation or transportation have been studied. The method and modes of heat treatment of blanks from finished 08Yu sheet steel to facilitate their deformability and improve stamping in order to reduce waste in the manufacture of products by cold deformatiion with deep and complex drawing were suggested.

Investigation of the influence of modification of the working tool for the manufacture of niobium case products

The main production of machine-building enterprises of various industries is the production of metal parts and products, 90-95% of which are manufactured using metal processing by pressure. Ensuring the stability of the technological processes of cold stamping is impossible without the use of interoperative coatings, which play the role of lubrication, preventing the diffusion “setting” (interpenetration at the atomic-molecular level) of the processed materials and tools. Therefore, one of the tasks in constructing the technology for manufacturing parts from these materials is to conduct a test cycle to establish the most acceptable coatings at the intermediate stages of processing. In the process of studying the operability and manufacturability, it is also advisable to use new methods for evaluating quality indicators at separate stages of processing semi-finished products and at the stages of control of finished products, which allows practically eliminating defects due to internal defects, ensuring the uniformity of the microstructure and predicting the operability of finished products during operation. Ensuring the quality of stamped semi-finished products made of refractory metals (niobium, molybdenum) is an urgent task due to the significant proportion of defects during cold stamping of these parts.

Topological Optimization of a Complex Shape Forming Stamp

The scientific research is devoted to the mathematical modeling of the optimal topology of stamps with a complex forming surface. Topological optimization is based on the SIMP method by creating a field of pseudo-densities and minimizing the pliability of the structure under the influence of load. When setting the problem, it is proposed to take into account the fatigue strength of polymers, taking into account the restrictions on the stress state. According to the results of the calculation in the ANSYS software package, an optimal redistribution of the stamp material and a reduction in volume due to the removal of elements that have little effect on the rigidity of the structure is obtained. The results of the study can be further applied in the field of hot and cold stamping by creating stamping tools of minimal volume.

Structural-Parametric Synthesis of the RoboMech Class Parallel Mechanism with Two Sliders

This paper addresses the structural-parametric synthesis and kinematic analysis of the RoboMech class of parallel mechanisms (PM) having two sliders. The proposed methods allow the synthesis of a PM with its structure and geometric parameters of the links to obtain the given laws of motions of the input and output links (sliders). The paper outlines a possible application of the proposed approach to design a PM for a cold stamping technological line. The proposed PM is formed by connecting two sliders (input and output objects) using one passive and one negative closing kinematic chain (CKC). The passive CKC does not impose a geometric constraint on the movements of the sliders and the geometric parameters of its links are varied to satisfy the geometric constraint of the negative CKC. The negative CKC imposes one geometric constraint on the movements of the sliders and its geometric parameters are determined on the basis of the Chebyshev and least-square approximations. Problems of positions and analogues of velocities and accelerations of the considered PM are solved to demonstrate the feasibility and effectiveness of the proposed formulations and case of study.

STRUCTURE AND PROPERTIES OF ROLLED STEEL AFTER SKIN-ROLLING ACCORDING TO DIFFERENT TECHNOLOGICAL PRODUCTION SCHEMES

Problem statement. Development of an effective technology for the skin-rolling will allow the production of hot-rolled sheet products with quality indicators that meet the requirements of standards for cold-rolled sheets. Consumers with significant economic benefits will be able to use relatively inexpensive hot-rolled sheets instead of expensive cold-rolled sheets. The purpose of the article: establishment of the effect of skin-rolling to various technological schemes for the production of hot rolled fine and thickness rolled for cold stamping on the structure and properties of the metal. Conclusion. The patterns of the formation of the structure and properties after skin-rolling of hot rolling sheet steel and plate steel for cold stamping are established. It is shown that with an increase in the degree of deformation during skin-rolling in the unit cutting unit, there is a decrease in the plasticity of hot-rolled plate steel strips of low carbon steels. As a result of heat treatment and skin-rolling on a separately located mill of hot rolled, thin-sheet low carbon steel, the plasticity of the metal rises and a homogeneous structure is formed in accordance with the requirements of ДСТУ 2834-94. Obtaining hot-rolled thin-sheet steel with quality indicators at the level of requirements for cold-rolled metal will allow the use of hot-rolled steel instead of cold-rolled one, which will ensure an increase in labor productivity and savings electricity.

Kinematic Synthesis and Analysis of the RoboMech Class Parallel Manipulator with Two Grippers

In this paper, methods of kinematic synthesis and analysis of the RoboMech class parallel manipulator (PM) with two grippers (end effectors) are presented. This PM is formed by connecting two output objects (grippers) with a base using two passive and one negative closing kinematic chains (CKCs). A PM with two end effectors can be used for reloading operations of stamped products between two adjacent main technologies in a cold stamping line. Passive CKCs represent two serial manipulators with two degrees of freedom, and negative CKC is a three-joined link with three negative degrees of freedom. A negative CKC imposes three geometric constraints on the movements of the two output objects. Geometric parameters of the negative CKC are determined on the basis of the problems of the Chebyshev and least-square approximations. Problems of positions and analogues of velocities and accelerations of the PM with two end effectors have been solved.

Development and Research of Copper Covering for Intensification of Cold Stamping of Products from Stainless Steels

The copper covering put in fused salts of chlorides at temperature of 450-500cC and preventing scuffs on the surface of steel of type 12X18H10T at cold stamping of case products and fixture was investigated. Metallurgical surveys have shown: 1) except cover zone and zone of base metal there is also transition zone, representing substitution type of solution; 2) in the course of application there is superficial alloying, due to penetration of atoms of copper deep into metal and diffusions of doping steel elements in coating material under the influence of melts's high temperature. The schedule of change of concentration of copper in diffusion zone allows to conclude that the copper covering consists not of pure copper, and that the alloy contains only 94% of copper; other 6% represent the chrome and the titanium diffusing in copper covering. It is established also that, despite strong cohesion with basis, the covering is completely removed from surface of the stamping details being dissolved in standard sulphuric acid solution.

An Infrared Local-Heat-Assisted Cold Stamping Process for Martensitic Steel and Application to an Auto Part

The automotive industry has tried to employ ultra-high-strength steel (UHSS), which has a higher strength with a thinner thickness. However, because of its low formability, there is a limit to the use of UHSS in industrial applications. Even though the hot-press-forming method can resolve the formability problem, elevated-temperature conditions lead to side effects—heat transfer and productivity issues. This work presents the concept of an infrared local-heat-assisted cold stamping process. Before the forming process, local areas, where the formability problem occurs, are locally heated by the gathering of infrared rays and cooled to room temperature before delivery. Since the heat treatment is completed by the material supplier, the stamping companies can conduct cold stamping without new investments or the productivity issue. In this work, a heat-assisted cold V-bending test was conducted with a martensitic (MS) 1.5 GPa steel, the CR1470M steel provided by POSCO. The heating effects on the microstructure, hardness, and local ductility were also observed. Finally, a commercial door impact beam was successfully manufactured with the present method. In this application, only a targeted small area was heated. The results show that the present method can improve the formability and springback problems of MS steel in the stamping process.

On the influence of the shaped charge liner manufacture technology on the high-speed element characteristics

The paper introduces the results of numerical simulation of the functioning of shaped charges, whose liners are made of different materials. As a result of their functioning, these charges form high-speed elements. Typically, liners for such charges are produced by the cold stamping technology. An alternative method for producing the liners is metal spinning. Moreover, a spin formed liner is expected to have higher physical and mechanical properties compared to a stamped liner made of the same material and having the same geometrical parameters. To reveal the patterns of molding high-speed elements from stamped and spin formed liners, the action of shaped charges comprised of steel or copper segmental liners of small bending, was simulated numerically using the apparatus of continuum mechanics. The influence of the liner manufacture method was taken into account by varying the values of the physical and mechanical characteristics of the liner material. The design parameters of the simulated charge, with the exception of the liner bending, during the calculation study remained unchanged and corresponded to the parameters of the currently used samples. Following the numerical experiments results, the study shows that the elements molded from spin formed liners are less likely to become fractured while being formed and are also more integral (continuous) in comparison to the elements molded from stamped shaped charge liners.