Papers by Keyword: Steel Pipe

Abstract: The occurrence of chatter during machining processes is a serious problem because of an excessive vibration that consequently dropped the quality of the machined surface. Especially on the turning process of tube shaped workpieces e.g. steel pipe that has relatively low stability limit represented by low critical depth of cut due to the naturally low dynamic stiffness of steel pipe. A cheap and simple method to increase the stability limits during the turning process of steel pipe has been developed in this research by using “Sand” as granular damper material to dissipate the elevated vibration energy. An experimental research is performed to investigate the performance of the sand damper by doing the cutting process of two different diameter the steel pipe that is filled up by sand. The result of the experiment shows that the 3 inch nominal diameter with fully filled of Sand can increase the stability limits from the critical depth of cut 0.68 mm (empty or without sand) up to 3.27 mm (full) or elevate by 4.8 times (almost fivefold). On the other hand, the 2.5 inch nominal diameter by filling with full of sand can improve stability limits from the critical depth of cut 0.95 mm (without sand) up to 3.05 mm or increase by 3.2 times. In simple words, the result of this research can be concluded that the increasing of the stability limits means also the elevated of the quantitative performance or the production rate of the turning process of Steel pipe almost up to fivefold. Keywords: Stability limits, chatter, sand damper, turning, steel pipe, vibration.

Abstract: This study indicated the deterioration of the steel pipe and beam structure in west coast Sumatra made of ASTM A252, and also pipeline along Riau land-Jambi - Batam Island. It was found that severest corrosion occurs at the rate up to 1.6 mm/year (63 mpy) on the steel cross beam-800 on west coast Sumatra. Whereas the corrosion rates on ASTM A234 and API 5L steel structures along the pipeline across Riau - Jambi - Batam occur from the high-to-severe up to 0.43 mm/year (17 mpy) mainly on pipe elbow 16” diameter. Due to this corrosion attack, the steel infrastructure requires whole protection including sacrificial thickness, surface coating, and cathodic protection. The corrosion attack data may be used to provide the required effort and its priority to protect the steel pile and pipe infrastructures on Sumatra Island.

Abstract: In this paper, a solution for temperature control in a tunnel heat-treatment furnace, used in metallurgy, is presented. The mathematical model of the heating technological process associated to the furnace is expressed using a system of ordinary differential equations and it results through analytical modeling. Based on the determined mathematical model, a temperature control structure which uses the Internal Model Control strategy is proposed. In order to obtain the restrictive control performances imposed by the heat-treatment procedure, the proposed temperature control structure contains two controllers which are tuned using an iterative method and which are used alternatively for the temperature control. The simulations of the temperature control system are presented in a comparative manner, highlighting the main differences between the solution proposed in this paper and the cases of using a classical integer-order controller and a fractional-order controller.

Abstract: A leak detection system using acoustic emission methods is developed. For this, an experimental rig to detect leak was built using 8” galvanized steel pipe. The length of the pipe is 2 meters. A leak was made with 3 mm diameter and located in 1 meter from the end pipe. The pipe was filled with water and compressed until certain pressure reached. An acoustic emission transducer from Brüel and Kjær type 8313 is mounted on the pipe wall and connected to digital oscilloscope to detect AE signal. The experiment conducted by placing a sensor at a distance of 15 cm, 30 cm, 45 cm, 60 cm, and 75 cm from the position of the leak. Measurements were also performed with the variation of the pressure 3 bar, 4 bars, 5 bars, 6 bars, and 7 bar for those points.Considering acoustic emission wave travelling on pipe is plane wave, leak detection using energy attenuation emission become possible that is different from the method commonly used. Propagation constant is thus required and obtained based on experimental result where the amplitude varies with the spatial and pressure. It is found that for the case considered here. Subsequently, distance of leak location can be determined by the propagation constant and the ratio of energy. Using this method, the error of prediction is about 15.8 %.

Abstract: In manufacturing car components, the hollow parts manufacturing method is useful for reducing the product weight, especially in drivetrain parts such as long shafts. Long, hollow shafts should have middle portions with large diameters and thin walls and end portions with small diameters and thick walls in order to reduce weight while maintaining pipe strength.Generally, such long shaft parts are manufactured by reducing the end portion of the pipes with the equivalent diameter and desired hollow part thickness for the middle portion of the parts. It is difficult for manufacturers to successfully thicken the pipe wall locally by press forming because pipes buckle easily during the process. Using thick pipe is one way to prevent buckling, but when using thick pipes, we could not reduce weight much. Automotive industries have desired a manufacturing process that can reduce pipes (relatively thin pipes) without buckling.This paper clarifies the relationships among the forming conditions and the thickening ratio (thickness after forming / thickness before forming) in uniaxial press forming by experiments and finite-element simulation. Steel pipes with 39.0mm outer diameter and 7.6mm thickness were used in the experiment. The relationship between the thickening ratio and the forming load that depends on the die shape, lubrication, and slide motion of the press machine was investigated. An appropriate manufacturing condition that could reduce pipes without buckling was obtained. We clarified that the pipe wall thickness could be increased ten percent. The details of material flows in reducing pipes without buckling were discussed using finite-element simulation.

Abstract: The paper deals with corrosion damage to steel pipes which were a part of the indirect cooling circuit of gas cleaning. The pipes were made from steel ASTM A106 Gr.B. The outer surface of pipes of the inside part of the circuit was affected by flue gases with mean temperature of approximately 1200 °C. The pipes of the outside part of the circuit were exposed to outer environment with mean temperature of about 25 °C. The cooling water flowing in these pipes had mean temperature of about 20 °C and contained a corrosion inhibitor based on zinc chloride (with addition of hydrochloric acid, phosphoric acid and PBTC). Flow rate of cooling water was 3700 m³/h, its total volume 1500 m³, and the pressure of cooling water was 600 kPa. The achieved thickening of cooling water was N=4. Side filtering was accomplished by a filter DPF 4000. The pipes of the cooling circuit were welded to each other, which initiated stress stimulating development of cracks on the outer surface of pipes in the heat-affected zone, Fig.1. The existing technological conditions resulted in formation of deposits on the outer pipe surfaces. Their presence changed thermal conditions in steel pipes.

Abstract: In order to verify the feasibility and validity of frequency ratio as diagnostic parameter in structural damage detection proposed in the Musical Tone Law Method (MTLM), steel pipes and three-story steel frame structure model tests are carried out. According to the experiment results, it is clear that the diagnostic parameter is effective for symmetrical structure in structural damage detection, such as cable structure, framed structure, and so on. Model tests prove that the frequency ratio is effective in detecting the 3mm width crack damage of steel pipe. In the damage detection test of three-story steel frame structure, the parameter also successfully diagnosed the damage caused by bolts loosening at the node of model.

Abstract: For tower structures located in high-intensity seismic zone, despite the importance of anti-seismic performance in flange connection, far less attention has been given to it. Based on finite element analysis results carried by ANSYS software, under pressure and moment, influence of stiffener height and axial compression stress ratio of steel pipe on the anti-seismic performance of flange connection was studied. The main results shows that lower axial compression stress ratio of steel pipe or higher stiffener height would improve the anti-seismic performance of flange connection. And closer flange connection from the end restraint would lead to better anti-seismic performance.

Abstract: Relationships among the forming conditions (such as shapes of dies, lubrication conditions, and slide motion of the press machine) and the thickening ratio (thickness after forming / thickness before forming) has been clarified in uniaxial press forming by experiments and a three dimensional finite element simulation. Steel pipes with 39.0mm and 7.6mm thickness were used in the experiment. The relationship between thickening ratio and the forming load that depends on the die shape, lubrication, and slide motion of the press machine was investigated. It has also been found that an eight percent increase of the wall thickness of the pipes could be possible without buckling. It has been clarified that thickening ratio during die forming could be predictable by using a finite element simulation.

Abstract: A new reinforcement measure with no-fire operation is presented, which is very suitable for space trusses which are located in gas stations. A finite element model (FEM) is presented with shell elements and multipoint constraint elements. With this FEM, nonlinear analyses are carried out. Analytical results show that integral failure of reinforced pipe is caused by yielding of original pipe inside. So it is not necessary to reinforce original pipe using steel pipe bonded outside with high yield strength. With the increase of length of bonded pipe outside, loading according to elastic stage and ultimate bearing loading increase, it is clear that the length of bonded pipe outside is an important factor which influences the bearing capacity.