Tube Drawing Research Articles

Using 2D/3D FEM Simulation to Determine Drawing Force in Cold Drawing of Steel Tubes with Straight Internal Rifling

The most comprehensive steel tube portfolio is used to produce all kinds of modern energy production and the corresponding auxiliary unit such as boilers and heat exchangers. Multi-rifled seamless steel tubes are distinguished by maximum pressure, heat resistance, strength and durability. Production of multi-rifled seamless steel tubes by cold draw process using multi-rifled mandrel is quite a new technology. Shape and dimension of the drawing tool depend on drawing tube reduction degree, i. e. on the original diameter of the initial tube and final diameter of the tube. The technology of drawing tubes is influenced by process parameters, dimensions of tools and cold forming process conditions. Optimization of the whole forming process naturally involve the FEM analyses and simulation. One of the most important information of the cold drawing process is the load stroke of the tools. The contribution is concerned at the usability of FEM simulation on an evaluation of cold draw forming process condition and prediction of load stroke of the forming tools. DEFORM 2D/3D FEM software is used to compare the result of the drawing force and to determine the appropriate methodology to set FEM simulation of cold forming.

Space mapping for optimal control of a nonisothermal tube drawing process

We implement space mapping technique for the first time to optimize geometry of a glass tube during its production process. The strategy is to align the optimizer of the coarse model (isothermal tube drawing) with the fine model (nonisothermal tube drawing) through space mapping technique in order to find an optimal solution of a control problem. Adjoint variable approach is used to find optimizer of the coarse model. Numerical results obtained through aggressive space mapping (ASM) algorithm are presented and discussed.

Simulation of rifled tubes drawing process

Presented paper is focused on knowledge in the field of tube drawing process. The introduction consists of summarizing the current state of the art. In the material and methods section, it is a characteristic of the usability of rifled tubes for heat exchangers, which serve to better heat exchange between the medium and the tube. The following section describes the implementation of the experiment. This section shows the principle of pipe drawing using a grooved mandrel and a die. The result section is showing resulting a simulation of strength analyzes and the recorded values during the pulling tests. In conclusion, the aim of this paper is briefly explained, as well as the need to take into account the leading part of the mandrel, which may result in incorrect geometry and cavitation. In conclusion, the issue is mentioned, which is beneficial for science and research in the field of cold drawing of tubes. It is also about knowledge with internally shaped surface in energetic equipment.

Failure and fracture analysis of a high-alloy Ni-Al bronze chain connector of a tube drawing machine

The investigation of a fractured Ni-Al bronze alloy connector, from a chain assembly, was performed in order to determine the potential cause of the observed failure. It is shown that the fracture occurred by fatigue due to the combined result of poor machining quality and the brittle nature of the as-cast component. This synergistic effect facilitated intergranular crack propagation through the “microstructurally sensitized” interdendritic regions. Various irregular and coarse-shaped intermetallic phases, corresponding to κ-type phases, were detected and their detrimental role on crack propagation was evaluated. Thermodynamic and kinetic simulation of solidification and phase transformation was elaborated in order to verify qualitatively and quantitatively the presence of the microscopically detected phases. Thermodynamic results were in agreement with metallographic observations. Kinetic results showed that increased cooling rate affects solidification particularly at high content of substitutional elements, such as Fe, Ni and Mn, since their diffusion is restricted and the completion of solidification is decelerated. Moreover, the high content of these elements favors the appearance of κΙ precipitates. The formation of shaped κΙ-phase cannot be eliminated, however its fraction and size can be suppressed by increasing cooling rate. The alteration of chemical composition of cast component could provide promising results as it shows a reducing tendency of κI-phase intermetallics’ formation and a higher homogeneity, even at moderate cooling rates.

Predicting the eccentricity of tubes by developing a multiple regression model in tube drawing process with tilted die

Designing an inline thickness-measuring- adjustable die to control the eccentricity, will need finding the relationship between the involved parameters in tube drawing, the materials’ properties and the new tube’s eccentricity. The wall thickness of the tube is measured inline during the drawing process. The measured wall thickness and the developed regression model are used to predict the optimum tilting angle and tilting position of the die. The importance of this research lies in its uniqueness and effectiveness of the regression model for the process automation. Minitab software as a statistic tool is used to determine and to select the effective independent variables in order to develop the suitable regression model. This model is then applied to predict the eccentricity after tube drawing. The independent variables include the tilting angle of the die, mechanical properties, forming ratio and the geometry of the tube. To this end, a regression model for copper-tubes was developed and was validated for different materials aiming to find a global regression model for all categories of materials. In case of more than one independent variable, the multiple regression model is more accurate than simple regression models. The main advantage of the developed regression model in this study lies in improving the performance of the tube drawing process that is conducted by an inline measuring self-regulation tilted die machine. The results indicate that through applying such an adjustable dynamic system, the eccentricity after tube drawing can be improved by more than 50% in one process step.

Parametric optimization of the generation of the porous layer for lubrication in tube drawing process

For severe metal deformation processes such as metal drawing operations, the use of porous lubricant carrier layer on metal surfaces has been proposed in recent literature for better lubricant retention and effectiveness under extreme conditions. The porous layer may be generated by different methods and the method chosen in this study involves electroplating a thin layer of an alloy of tin and zinc on the parent metal and subsequent selective etching of zinc. The aim of this study is to optimize parameters for specific application of the new technique in steel tube drawing operation using Taguchi's experimental design procedures. Experiments are designed based on three controllable factors namely electric current density, process time and Sn-Zn composition by weight in electrolyte at three levels. L9 orthogonal array is used for this study. The regression models have been constructed for drawing force and surface roughness along with verification of the model fit using (R2) values and analysis of variance (ANOVA). The optimal values for parameters have been identified using signal to noise (S/N) ratio. All the calculations are obtained by using Minitab software. The optimal levels for: current density (I) is 1 A/cm2; for plating time (T) is 12 min and; Sn:Zn composition is 1:6. This study may pave the way for industrial adoption of the new technique of using porous layer in tube drawing operations to bring out the associated benefits of doing away with the conventional lubrication systems that have proven environmental hazards.

Evaluation of strain in cold drawing of tubes with internally shaped surface

Abstract Presented article is focused on strains acting in cold forming process of drawing tubes with shaped internal surface. At present, mathematical simulation, tools make it possible to significantly shorten the deadlines for pre-checking the possibilities of very complex processes. Pulling pipes with an internal shape with a broken surface is a complex problem with many deformation zones. The principle of the shape of the broken pipes is very similar to pulling smooth pipes. In the process, the same dies as the drawing of smooth pipes are used. Courses of total and axial strain describe the transformation of an object from an initial state to the final shape of the tube

The clinical application and significance of TcpCO2 after weaning of machanical ventilation in very or extreme low birth weight infants

Objective To analysis the transcutaneous carbon dioxide pressure(TcpCO2)in very low birth weight infant (VLBW) and extremely low birth weight infant (ELBW) after the time of tube drawing, and further guidance the management of premature ventilator breathing. Methods Premature infants with gestational age less than 32 weeks, birth weight below 1 500 g, hospitalized from March 2016 to December 2018 in our hospital, who needed early mechanical ventilation due to respiratory distress within 24 hours after birth and intended to be withdrawn were enrolled.Fifty-five infants in the observation group were monitored by TcpCO2 and blood gas was collected at 1 h, 6 h, 12 h, 24 h, 48 h, and 72 h after weaning; 55 infants in the control group were collected arterial blood gas only.When TcpCO2 monitoring and PaCO2 indicated hypercapnia, clinical intervention was actively given.The value of blood gas PaCO2 in the two groups and the TcpCO2 value of the observation group were recorded at different time points (1 h, 6 h, 12 h, 24 h, 48 h, 72 h) after weaning, and the failure of weaning was recorded in both group. Results There was no significant difference in the general information (gender, gestational age, birth weight, and whether prenatal maternal glucocorticoids) between the two groups (P>0.05). There were no significant differences in mechanical ventilation time, noninvasive ventilation mode and time between the two groups(P>0.05). The failure rate of withdrawal within 24 h and 72 h was lower in the observation group than the control group[3.6% (2/55) vs.14.0% (8/55), 7.3% (4/55) vs. 21.0% (12/55)], the difference was statistically significant (P 0.05). The values of TcpCO2 and PaCO2 had no significant difference in the observation group at the same time point (P>0.05), and there was a correlation between them(r=0.761, P<0.05). Conclusion VLBW and ELBW undergoing mechanical ventilation are given continuous TcpCO2 monitorings after weaning, which not only has the characteristics of continuous and non-invasive monitoring, but also help to identify hypercapnia early and give symptomatic treatment, and reduce the incidence of weaning failure.And it proves a good correlation between TcpCO2 and PaCO2. Key words: Transcutaneous carbon dioxide pressure; Partial pressure of carbon dioxide; Extubation withdrawal; Very low birth weight infant; Extremely low birth weight infant

Novel Thermostable Inhibitor of Contact Activation Tica Effectively Blocks Contact Activation in Low Tissue Factor Thrombin Generation

Background: Thrombin generation and other clotting assays suffer from a wide variation of pre-analytical variables. One of those pre-analytical variables is contact activation through blood withdrawal methods, different syringes, differences in blood coagulation tubes, blood transport and sample handling. It has been shown that the addition of contact activation inhibitors in low tissue factor activated thrombin generation leads to a correction of the, in these circumstances significant, increase in thrombin generation due to contact activation. We compare the novel 'thermostable inhibitor of contact activation' (TICA) to the current standard 'corn trypsin inhibitor' (CTI). Aim: Comparing the effectiveness of novel contact activation inhibitor TICA to the current standard CTI in low tissue factor-induced thrombin generation and recalcification in sodium citrate anticoagulated platelet poor plasma (PPP) and platelet rich plasma (PRP). Methods: We compared TICA, Corn trypsin inhibitor and plasma without contact activation inhibitors in low tissue factor PPP thrombin generation and in PRP recalcification thrombin generation, the latter the most sensitive condition for contact activation. In addition, we compared low tissue factor activated thrombin generation in plasma from severe hemophilia A patients with and without TICA during and after blood drawing. Thermostability - as a measure of shelf life - was measured and compared to CTI. Results: TICA is able to fully block contact activation in PRP recalcification experiments and is comparable to CTI in doing so. TICA significantly lowers low tissue factor induced thrombin generation by blocking contact activation. Pre-loading vacuum blood collection tubes with contact activation inhibitors is superior in inhibiting contact activation compared to addition of the inhibitor during the thrombin generation assay itself. TICA did not alter coagulation activity when added to FXIIa deficient plasma in thrombin generation. In contrast to CTI TICA is heat stable which will be of benefit to shelf life of pre-loaded blood drawing tubes. Conclusion: TICA is able to fully block contact activation and has several advantages over CTI. Disclosures No relevant conflicts of interest to declare.

Effect of lubrication technique in tube drawing

Cold drawing process is widely used in steel tube manufacturing industry as it offers advantages like close dimensional tolerances, superior surface finish, flexibility in achieving different sizes and manipulated mechanical properties. This process needs to control friction parameters and lubrication extensively in order to obtain acceptable quality tubes and generally a phosphate and stearate coating has been the conventional approach to achieve this objective. Off late, some alternatives have emerged and a recently developed alternative lubrication system based on micro-porous lubricant carrierlayer generated on steel tube substrate by electroplating an alloy and selectively etching out one component of the alloy has been specifically taken up for detailed study. The porous layer is to trap the lubricant and act as lubricant reservoir in the metal deformation zone under the extreme pressures of cold drawing process. The attempt has been made to practically investigate the effectiveness of this alternative lubrication system for cold drawing process in tube manufacturing from an industrial perspective. Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscope (SEM) has been used in the analysis to verify that the aimed chemical composition and uniform distribution and to visualize the generated porous layer. Experimental investigations were carried out by subjecting the tube specimens (with lubricated porous layer) to the cold drawing process carried through a special drawing die attachment mounted on Universal Testing Machine (UTM). Comparison of the results with the conventional phosphate and stearate film based lubrication method has been made. The results show 10% of reduction in draw load and about 40% of improvement in surface roughness.

Conditions for Wall Thickness Reduction in Hollow Sinking of SUS304 Tubes With Drawing Speed Control in Entrance and Exit Sides of Die

Abstract In this study, the conditions for wall thickness reduction in hollow sinking were obtained by tube drawing experiments in which the drawing speed ratio was controlled under three conditions (1.09, 1.11, and 1.14). These conditions have not been found in the history of hollow sinking. The results of the experiment and the theoretical formulas indicate that the geometric condition is obtained from the figure of the ratio of inner diameter to outer diameter after drawing against that ratio before drawing. Furthermore, the ratio of the inner diameter to the outer diameter after drawing must be above the constant wall thickness line derived from the cross-sectional change. To satisfy this geometric condition, the drawing speed ratio must be larger than the threshold value, which is obtained from the ratio of the inner diameter to the outer diameter before drawing, and the reduction of the die. However, the value of the back stress approaches that of the strength of the tube when the drawing speed ratio increases. A simple dynamical model shows that parameters other than the drawing speed ratio do not significantly decrease the back stress during drawing. Therefore, the drawing speed ratio should be set such that the tube does not break.

Theoretical analysis of tube drawing process

Theoretical analysis of tube drawing process

The influence of reduction on the surface temperature in the process of drawing tubes

The influence of reduction on the surface temperature in the process of drawing tubes

The Influence of Technological Parameters on Drawing Force at Cold Drawing of Steel Tubes Using FEM Simulation

The process of cold die drawing of tubes is ranked among frequently used methods of production of seamless tubes and is performed in drawing tool which is characterized by simple design. Shape and dimensions of the drawing tool depend on tube reduction degree, i. e. on original diameter of initial tube and final internal diameter of the tube. Tube wall thickness is not determined by any tool. The technology of cold die drawing of tubes is influenced by various process parameters, i.e. geometry of the die itself, strain degree and strain rate, force conditions, conditions of friction, method of lubrication and the type of used lubricant. The contribution is concerned with evaluation of influence of the selected process parameters using FEM simulation. Designed graphs illustrate the impact of coefficient of friction and reduction cone of drawing tool on the size of drawing force.

The Research of Influence of Strain Rate in Steel Tube Cold Drawing Processes Using FEM Simulation

The technology of cold die drawing of tubes is used for processing of metals and alloys with good or worse formability, while the tube production itself is affected by various process parameters, i. e. mostly die geometry, strain degree and strain rate, force conditions, conditions of friction, method of lubrication and type of used lubricant. The paper is concerned with an evaluation of influence of the selected process parameters, i. e. drawing tool geometry and strain rate on plastic flow and energy intensity of the process of cold die drawing of tubes. The FEM analysis of the drawing process was an important aid for this research. The computer simulation resulted in interesting graphs illustrating the influence of the shape of the drawing tool reduction cone on the size of the drawing force at various strain rates.

Evolution of texture in precision seamless tubes investigated by synchrotron and neutron radiation measurement

High precision dimensionality tubes are required for a number of applications. Nevertheless, there are some troubles and challenges to produce high quality tubes in a cost-effective way. In recent works done at the Institute of Metallurgy at Clausthal University of Technology, the tube drawing process was optimized by introducing dynamic tilting and shifting of the die. These methods made it possible to control the wall-thickness variation and even residual stresses (RSs) evolution. A possible influence on texture evolution, however, has not yet been investigated, though it is well known that the crystallographic texture has a remarkable effect on materials' properties. Furthermore, the initial texture clearly influences the microstructural evolution during plastic deformation, affecting the RSs evolution and dimension accuracy, too. In this paper the evolution and heterogeneity of the texture are introduced for tube drawing performed with a tilted die. The measurements were done using synchrotron and neutron diffraction methods. The aim was to understand the behavior of the material during the asymmetrical tube drawing, caused by the tilted die, and connect the effects between eccentricity and residual stresses. Pole figures and ODF densities were studied and the creation and variation of different texture components were analyzed as well.

Application of evidence-based nursing in blind intubation of helico-nasointestinal tube in patients with stroke-associated pneumonia in intensive care unit

Objective To study the effect of evidence-based nursing in patients with cerebral apoplexy in ICU by blind bedside spiral nasointestinal tube application. Methods To choose between September 2016 and September 2017 in our hospital ICU were 140 cases of patients with cerebral apoplexy as analysis object, randomly divided into two groups, two groups all use bedside blind spiral nose long intestinal tube technology, the control group using conventional nursing method for nursing, observation group using evidence-based nursing intervention, compared two groups of a success rate of catheter, accident to take off the tube (unscheduled decannulation rate), reflux hiccups, vomiting incidence of aspiration and patient satisfaction. Results The success rate of catheterization in the observation group was higher than that in the control group, and the incidence of accidental catheterization was lower than that in the control group. The incidence of reflux hiccup and vomiting aspiration was significantly lower than that in the control group, and the patient satisfaction was higher than that in the control group (all P<0.05). Conclusion For patients with cerebral apoplexy in the ICU bed of blind plug spiral nasal bowel technology combined evidence-based nursing intervention, clinical effect is remarkable, improve the success rate of catheter, reduces the surprise success rate of tube, unscheduled tube drawing number, reduces the incidence of reflux hiccups, vomiting aspiration, improve patient satisfaction and quality of life. Key words: Evidence-based nursing; Intensive care unit; Spiral nasal catheter blind insertion technique; Nasogastric tube placement technique

Differences between patient demands after tracheal intubation and cognition of nurses in intensive care unit

Objective To explore the differences between communication demands of tracheal intubation patients and cognition nurses in intensive care unit (ICU) . Methods We selected 105 tracheal intubation patients after the cardiac surgery and 19 nurses provided nursing for them as subjects at Peking University First Hospital by convenience sampling. All of the patients and nurses were investigated with the communication demands scale of tracheal intubation patients, and the differences between them were compared. Results The total score of demands of tracheal intubation patients was (99.96±24.93) lower than that (123.11±19.48) of cognition of nurses with a statistical difference (P<0.05) . The highest communication demand of patients was the item of I want to know the time of tube drawing with (3.33±1.09) for the score ranked fourth in cognition of nurses. The scores of items in demands of love and belonging as well as self-esteem of patients ranked more than the tenth. Conclusions There are differences between communication demands of tracheal intubation patients and cognition of nurses in ICU especially in physiological needs, safety needs as well as the need of love and belonging. Encouraging patients to express intentions, understanding patients' intentions and avoiding forming the fixed thinking can carry out nursing service better so as to provide the best scientific basis for patients' disease recovery. Key words: Intensive care units; Intubation, intratracheal; Cognitive differences; Demands; Nursing

Development and Introduction of Technology and Equipment for Multiple Drawing of Copper Alloy Thin-Walled Tube on a Long Movable Mandrel Without Intermediate Heat Treatment

Thin-walled and extremely thin-walled tubes made of copper alloys, i.e., brass grades L96, L68, L63, LANKMts, and the bronze grades BrOF6.5-0.15, BrOF4-0.25, are in great demand in the aircraft, shipbuilding, automotive, defense, diesel-locomotive building, and instrument-making industries. A promising manufacturing method is multiple drawing on a long movable mandrel without intermediate heat treatment due to such advantages as high total elongation ratios (λ = 3.0–6.0), simplicity of the equipment of the flow line, high productivity equal to 1200–1600 m/h, as well as good pipe surface quality and size precision. These advantages of the new method of manufacturing cold-deformed pipes make it possible to reduce the cyclic nature of manufacturing and processing costs. The work provides a methodological basis of theoretical analysis and design of rational routes for manufacturing colddeformed pipes by multiple deformation without intermediate heat treatment. As an example, the results are presented for calculation of three-fold drawing of thin-walled pipes made of brass grades L96, L68 and L63. Research results are used in the development of innovative technology for pipe manufacture from copper alloys at the PAO Revda Non-Ferrous Metal Processing Plant using a highly efficient three-fold drawing line on a long movable mandrel. One of the versions for line equipment layout is provided.

Feasibility of supraglottic tracheal tube ventilation during painless fiberbronchoscopy

Objective: To evaluate the feasibility and safety of supraglottic tracheal tube ventilation by comparing with modified laryngeal mask airway ventilation during painless fiberbronchoscopy. Methods: This was a prospective study. Twenty-eight patients undergoing painless fiberbronchoscopy in Hangzhou First People's Hospital were randomly divided into 2 groups(n=14): supraglottic tracheal tube ventilation(group A) and modified laryngeal mask airway(group B). MAP, HR, SpO(2), P(ET)CO(2) and BIS were recorded after entering the operating room(T(0)), after anesthesia induction(T(1)), immediately after inserting laryngeal mask airway or tracheal tube(T(2)), fiberbronchoscopy inserting(T(3)), at the end of the operation(T(4)), and at the recovery of patients' consciousness(T(5)). The arterial carbon dioxide partial pressure(PaCO(2)), the time spent in successful positioning of the tube, the endoscope indwelling duration, operative time, tube drawing time, patients' awakening time, satisfaction of operators, adverse events during anesthesia, the numbers of bucking or body moving were also recorded.The dose of propofol and remifentanil were also statisticed. Results: P(ET)CO(2) in group A at T(0), T(1), T(2), T(3), T(4), T(5) were (36.9±4.1), (36.3±4.7), (38.1±5.6), (40.4±4.0), (48.8±7.7), (45.3±7.6) mmHg, P(ET)CO(2) in group B were (38.6±4.4), (37.8±5.6), (37.8±5.4), (37.4±6.7), (43.3±12.2), (43.5±8.0) mmHg, at the end of operation, the P(ET)CO(2) at T(4) and T(5) were significantly higher than at T(0) in group A and group B (F=14.582, 12.651, all P<0.05). The PaCO(2) in group A was (62.0±4.7) mmHg , which was significantly higher than group B at the end of operation[(51.9±4.2) mmHg, t=2.432, P<0.05]. The time spent successfully positioning the insertion in group A and group B were (17.6±7.5), (29.8±13.6)s, the endoscope indwelling duration were(0.8±0.1), (1.4±0.3)min, and the operation time were(32.3±4.3), (46.8±4.8)min, there were significantly difference between group A and group B(t=2.670, 2.214, 2.166, all P<0.05). There were no significantly difference of the numbers of bucking or body moving , the satisfaction of operators and patients, and adverse events (all P>0.05). Conclusion: Supraglottic tracheal tube ventilation for painless fiberbronchoscopy is a safe and effective procedure.