STUDY OF THE PROCESS OF STAMPING BY ROLLING RING BLANKS OF PARTS FROM A SQUARE BILLET

Schemes and methods of manufacturing parts such as disks from square blanks obtained by stamping are studied. The possibility of controlling boundary conditions, creating various schemes of stress-strain state in local zones, changing the nature of metal flow, providing relatively low levels of residual stresses and anisotropy of mechanical properties in the longitudinal and transverse directions, allowing to stamp rolling workpieces. It is shown that in the technological process of stamping by running-in of annular workpieces of parts from a square workpiece, a metal displacer passes in different axial directions of the workpiece through three stages of forming. Deformation resistance throughout the volume of the part is also different. As a result, there are additional stresses: on the outer surface - compressive, as each inner layer restrains the movement of the neighboring outer, and in the inner - stretching, as each outer layer, moving faster than the neighboring, captures it. The device of manufacturing of details of type of disks from square preparations is offered in work. The principle of operation of this device is that the original workpiece with a square cross section before installation in the matrix is pre-fixed relative to its angles. As a result of stress equalization, there is a zone of inner layers with additional radial stress, which increases to the outer. The use of the device proposed in the work makes it possible to stamp parts without waste, to expand the range of products obtained, as well as to reduce the cost of manufacturing the product by facilitating the flow of metal. The calculation formula for determining the size of the original square workpiece is proposed. The choice of the sizes of initial preparations according to the calculation formula simplifies their preparation by felling, facilitates centering at stacking in a stamp, and the main thing provides high accuracy of the size on height and absence of anisotropy unlike the circles cut out from a sheet.

Residual Stress Analysis of a 2219 Aluminum Alloy Ring Using the Indentation Strain-Gauge Method

Aerospace thin-walled rings are vulnerable to machining distortion during the manufacturing process. Various research results show that the main factor causing machining deformation is initial residual stress inside the blank. In this study, the residual stress of a 2219 aluminum alloy ultra-large rolling ring was measured by using the indentation strain-gauge method. Results showed the maximum residual maximum principal stress was +265 MPa and stress distribution was uneven. To homogenize the initial residual stress of the ring, an expansion method is proposed based on the principle of pre-stretching plate, and the feasibility of the expansion method was analyzed by establishing a simplified theoretical model of ring. A FE (Finite Element) model was established to investigate residual-stress evolution during the rolling ring and the expanding ring process. The expansion simulation results show that the reduction rates of residual stress were greater than 40% and the maximum residual stress was only 65 MPa.

Selection of the optimal version of the rolling rings of stand no. 7 of mill 150 of OJSC “BSW Management Company of Holding “BMC” from various types of high-speed steel, providing the best indicator of operational durability

Rolling rings as an important element of the rolling mill belong to the category of replaceable equipment, the quality of performance of which affects a number of operational characteristics, as well as the quality of rolled products. The material from which the rolling ring of the stand No. 7 is made must have the appropriate properties capable of perceiving high thermal loads for a long period of time without destruction, chipping and significant development of calibers. In this regard, there is a need to select the optimal option for the manufacture of rolling rings that can withstand such loads for a sufficiently long period of time. The study of the causes of destruction of the rolling ring 450×242×100 mm of high-speed steel, used at OJSC «BSW – Management Company of the Holding «BMC» in the cage number 7 mill 150 rolling shop. The results of metallographic studies of the microstructure and chemical composition of fragments of the destroyed rolling ring are presented. A detailed study and comparative analysis of the chemical composition and microstructure of samples of similar rings made of high-speed steel from two different suppliers, which showed high results in durability during operation, was carried out.

Determination of Influencing Factors on Ring Climbing in Radial-Axial Ring Rolling via Design of Experiments

Seamless rings are applied in several industrial sectors and are mainly produced by radial-axial ring rolling. Ring climbing is one of the most occurring process errors leading to a distortion of the ring’s cross section. This paper presents the determination of the influencing factors and their impact and correlations on the process error of ring climbing via Design of Experiment. The highest impact on the climbing height of a ring has the adjustment of the rolling table and the guide rolls. Relatively low but still noticeable is the influence of the process parameters of the rings displacement and the unequal axial rolling speeds. With this knowledge it will be possible to develop, test and implement a rolling strategy that may reduce or avoid ring climbing successfully.

Hot Working Manufacturing Process of Large Mine-Used Rotary KilnRolling Ring Forgings

Bearing the gravity of rotary kiln barrel and the pressure between riding wheel and rolling ring, the surface defects appeared on casting large rotary kiln rolling ring, which caused large maintenance cost. While the life cycle of the rolling ring would be prolonged by using forging instead. The manufacture processing of large rotary kiln rolling ring was explored for changing casting to forging. The reasonable processing of smelting, forging and heat treatment were established.