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In order to improve the quality of welded joints and increase the service life of pipelines, ABAQUS finite element software was used to simulate the temperature field of 18,4 mm thick X80 pipeline steel in multi-layer and multi pass welding. The peak temperature of different passes was compared, and the change trend of temperature field in the welding process was obtained. The results show that the peak temperature of the weld and its adjacent areas is higher, and the peak temperature of the weld center is the highest. Due to the fast welding speed, the heat cannot be transferred to other areas in time, resulting in uneven heating of the entire test panel. [ABSTRACT FROM AUTHOR]

To obtain the exact mechanical properties of TC4 titanium alloy, the compression experiments on TC4 titanium alloy at different strain rates (10-2,10-3,10-4 s-1) were performed at room-temperature on the MTS-810 electrohydraulic servo material testing machine. The data of TC4 titanium alloy compression experiments at different rates were obtained. And furthermore Johnson-Cook constitutive model is established. Due to different conditions, the equation is simplified, the constitutive parameters are obtained by step-by-step estimation method, and the Johnson-Cook (JC) constitutive model of TC4 titanium alloy at room temperature is established. The prediction results of the model were compared with the experimental data, the prediction curve is in good agreement, which verifies the feasibility of the model. [ABSTRACT FROM AUTHOR]

Using Gleeble-3800 thermal simulation testing machine, the TC4 titanium alloy was subjected to hot compression experiments under the conditions of deformation temperature of 810 – 950 °C, strain rate of 0.001 - 1s-1. The research shows that the flow stress of TC4 titanium alloy is more sensitive to the deformation temperature and strain rate during thermal deformation, and it increases with the decrease of the deformation temperature and the increase of the strain rate. Based on BP neural network, a constitutive model of TC4 titanium alloy α+β two-phase region is established. The correlation coefficient reaches 0,996, which proves that the model can predict the high temperature flow stress of TC4 titanium alloy. [ABSTRACT FROM AUTHOR]

The Gleeble – 3500 thermal simulation testing machine was used to perform isothermal tensile test on 7075 aluminum alloy at a deformation temperature of 300 – 450 °C and a strain rate of 0,01 – 1 s-1, and the true stress-strain curve of the alloy was obtained. Based on the true stress-strain data, the modified Zerilli-Armstrong (M-ZA) model was used to construct the constitutive model of the alloy, and the fitting accuracy of the model was analyzed. [ABSTRACT FROM AUTHOR]

Use Gleeble-3800 thermal simulation test machine to conduct thermal tensile test on 6005A aluminum alloy at 623~723 K and 0,01~1 s-1 strain rate. Using the obtained true stress-strain curve, the modified Zerilli-Armstrong (m- Z-A) model considering strain compensation was used to construct the constitutive model of the alloy. The results show that the correlation coefficient and average absolute error of the m-Z-A model are 0,97311 and 4,1779 %, respectively. The experimental data is in good agreement with the predicted curve obtained by calculating the model, which verifies the feasibility of the model. [ABSTRACT FROM AUTHOR]

The deformation behavior of 6005A aluminum alloy at a strain rate of 0,01-10s-1, a deformation temperature of 673- 773K and a total strain of 0,8 was studied. Using the stress-strain data of 6005A aluminum alloy with a strain of 0,05- 0,8, an Arrhenius-type constitutive model was established. And verified the accuracy of the model. The results show that: the flow stress of 6005A aluminum alloy increases with the increase of strain rate, and decreases with the increase of deformation temperature; Under different strains, the correlation coefficient (R) between the experimental value and the predicted value is as high as 98 %, and the average relative error (AARE) is less than 10 %, indicating that the established model has high predictability. [ABSTRACT FROM AUTHOR]

This article takes the 21 - 4N engine valve as the research object and studies the effects of die forging temperature (1 000 - 1 180 °C), die forging speed (0,15 - 200 mm / s) and friction coefficient (0,1 - 0,5) on die forging results. First, a finite element model (FEM) of the valve blank and die is established using Creo; next, the valve forging process is simulated using Deform - 3D; then, the response surface analysis method is used to analyze and discuss the results of die forging, and to optimize the process parameters with valve product damage as the optimization goal, and determine the best process parameters for 21 - 4N engine valve forging; finally, the obtained parameters are verified through experiments, and the experimental results and prediction results have a good consistency. [ABSTRACT FROM AUTHOR]

The 3Cr23Ni8Mn3N heat-resistant steel was subjected to isothermal constant strain rate compression experiments using a Gleeble - 1 500D thermal simulator. The thermal deformation behavior in the range of deformation temperature 1 000 - 1 180 °C and strain rate 0,01 - 10 s-1 was studied. Based on experimental data, the stress-strain curves of 3Cr23Ni8Mn3N were established. And the constitutive relation of BP neural network (3 × 10 × 10 × 1) was constructed. The flow stress was predicted and compared by the ANN constitutive model. The correlation coefficient (R) is 0,999, and the average relative error (AARE) is 0,697%. The results show that the ANN constitutive model has high accuracy for predicting the thermal deformation behavior of 3Cr23Ni8Mn3N. The model can provide a good reference value for thermal processing. [ABSTRACT FROM AUTHOR]

The effect of grain growth on 21-4N heat resistant steel was studied by static grain growth test. The experimental results show that the temperature inhibits carbide grain growth is between 1 000 - 1 120 °C. When heat preservation time is over 40 min, the driving force of grain boundary is balanced with binding force of carbide nail, grain size will not grow up. There is no limit of grain size due to no pinning effect of carbides when the temperature is above 1 180 °C. Based on the theory of grain boundary migration, the grain growth model of 21-4N heat-resistant steel was established, and the relationship between the average grain size and the time of heat preservation at different temperatures was predicted. [ABSTRACT FROM AUTHOR]

There are many uncertain factors in the test process of electroplating zinc. The establishment of control standards in the research process can reduce the workload and shorten the test cycle. Based on the electrochemical module developed by COMSOL multi-physics software, this study uses the computer's powerful computing power and the existing perfect theoretical system to simulate the experiment. The results show that the potential at the anode plate is higher, the potential at the cathode plate is lower, and the potential distribution in the middle area of the two plates is relatively uniform. When the plating time is 10 min, the outer surface of the galvanized part is basically coated with a relatively uniform zinc coating, which is about 2μm. Due to the large local current density in each edge area of the sample, the plating layer is relatively thick, but the difference is not large. [ABSTRACT FROM AUTHOR]

In the process of hoisting the memorial archway, because the balance beam directly lifts the memorial archway, it is easy to deform during the hoisting process, and the deformation will affect the follow-up work, resulting in the delay of the project progress. In order to avoid this situation, the existing conditions are used to calculate the load that the balance beam can bear. Using 3D modeling and numerical simulation software, conduct force analysis on the balanced beam, and compare the simulation results with the calculated values to determine whether the stress and deformation of the balanced beam meet the requirements. The simulation results show that the stress on the balance beam during the lifting process does not exceed the maximum yield stress of its own material, which meets the requirements of the working conditions. [ABSTRACT FROM AUTHOR]

In the process of carrying out the installation of large flue, because the thickness of the flue is thin, it is easy to deform when hoisting with wire rope, and too much deformation will affect the subsequent use of the flue, resulting in waste, so in order to reduce the deformation of the flue, the existing conditions are utilized, and the bracket is added inside the flue to play the role of support, and the deformation of the flue is reduced. Using 3D modeling and numerical simulation software, the flue structure before and after adding supports was modeled and numerically analyzed, and the two simulation results were compared, and the deformation of the flue after adding supports was analyzed to be relatively obvious under the action of hoisting. [ABSTRACT FROM AUTHOR]

In the process of contemporary industrial pipeline installation, most pipelines must be cleaned before being put into use due to production and operation process requirements. This paper takes the offline trough cleaning of pipelines as the research object, and explores the evolution process of the metal microstructure under this cleaning method and the best cleaning conditions under the influence of the three factors of concentration, temperature and time. [ABSTRACT FROM AUTHOR]

The downhole expansion process of the expansion tube is the dynamic deformation process of the expansion tube metal material at different temperatures. In this paper, the dynamic tensile test is used to measure the dynamic tensile stress-strain curve of low-carbon alloy steel in the temperature range of 25 - 300 °C. upon analyzed the dynamic tensile test results, with the strain rate factor Z and McCormick physical model, the paper set up low carbon alloy steel constitutive equation of underground temperature field. The calculation results of the Sellars creep equation are compared with the residual stress value after expansion in the finite element analysis of the solid steel pipe expansion to verify the actual application reliability of the steel for the expansion pipe with high expansion rate. [ABSTRACT FROM AUTHOR]

Lifting is to use lifting equipment to lift components and install them to the designated position. On the main structure, lifting equipment is used to transport the flue and transport the sectional flue to the designated position. Certain deformation will occur during the lifting operation of the flue due to its force condition, but it is not known whether it is elastic deformation or plastic deformation. Therefore, this paper analyzes the stress and strain of the flue during operation by finite element method, and observes and analyzes the influence of plastic deformation on the whole flue. [ABSTRACT FROM AUTHOR]

Use Gleeble-1500D thermal simulation test machine to conduct thermal tensile test on AISI 1035 in the deformation temperature range of 1 173,15~1 373,15 K and strain rate range of 0,2 ~ 20 s-1. Using the obtained true stress-strain curves, an intrinsic model of the material was constructed using a model considering strain compensation. The results showed that the correlation coefficient of the Arrhenius model of AISI 1035 considering strain compensation was 0,984 with an average absolute error of 3,550 %, which can accurately predict the flow profitability. The experimental data matched well with the prediction curves obtained from the model calculation, which verified the feasibility of the model [ABSTRACT FROM AUTHOR]

For the fatigue failure of 42CrMo, the tensile test was performed on the CT specimen at different load ratios using a fatigue tensile tester. Data on the fatigue crack growth rate of the material and the crack tip factor were obtained. Scanning electron microscopy (SEM) was used to observe the microstructure and crack initiation and propagation of fractures. The crack initiation and propagation path law during fatigue crack propagation were obtained. The fatigue crack life was calculated by Paris formula, and the fatigue crack growth test and microscopic observation were compared. The propagation law and fatigue crack life of different stages of crack propagation were analyzed. The results show that the stable propagation stage of fatigue crack propagation is the key stage to determine fatigue fracture, the rate of growth is related to the stress ratio. [ABSTRACT FROM AUTHOR]

According to the practical engineering application, three-dimensional modeling of electric hoist and I-beam track is carried out, and the model is simplified to determine the electric hoist load, roller acceleration and speed, and the Abaqus software is used to simulate, analyze the simulation results, observe the actual maximum load under the track stress and strain to meet the requirements, calculate the allowable stress, Observe whether it exceeds the allowable stress and whether plastic deformation occurs. If the numerical simulation results of stress and strain are within the safety requirements, the project can be implemented. [ABSTRACT FROM AUTHOR]

Q235 steel components have poor corrosion resistance and are susceptible to erosion by corrosive media, so they are generally passivated before being put into service. This paper investigates the corrosion behaviour and corrosion mechanism of passivated Q235 steel in atmospheric environments through macro and micro morphological characterisation and electrochemical simulation analysis. [ABSTRACT FROM AUTHOR]

In this study, a 72-h neutral salt spray test was conducted on two low-carbon alloy steels and their corrosion kinetic equations were constructed, and tensile tests were conducted on specimens with different corrosion cycles to evaluate the mechanical properties of the two experimental steels. The test results showed that the corrosion resistance of TZ750MS was better than that of H750MS during the whole test cycle; however, the predicted results of the corrosion kinetic equation showed that the corrosion resistance of TZ750MS was lower than that of H750MS after 144 h. The tensile test results showed that the strength of both steels did not change substantially after corrosion, and the tensile stress-strain diagram showed that the specimens would fracture earlier after passing through the plastic deformation zone. [ABSTRACT FROM AUTHOR]

In this study, AISI 1035 steel was selected as the research object, and a single-pass thermal compression simulation experiment was carried out. Based on the true stress-strain curve obtained from the experiment, the dynamic DMM thermal processing map theory was used to draw the material under different thermal deformation conditions. and the rheological instability map based on the Prasad instability criterion, and the thermal processing map is used to predict the suitable processing interval and rheological instability interval for the thermal deformation process of the material under different process conditions. So as to provide theoretical support for the optimization of the material processing technology. [ABSTRACT FROM AUTHOR]

Design the wheel mold according to the cross-sectional view of the lightweight aluminum alloy wheel profile, determine the length of its working belt and use HyperXtrude software to simulate it, verify the rationality of the working belt design, analyze the flow velocity and temperature of the mold outlet, and determine the 7075 aluminum alloy The alloy wheel profile is most reasonable to be produced on a 10 MN extruder. Finally, the optimized working belt length is used for production. The quality of hot extrusion profile is qualified, which proves the accuracy of the simulation. [ABSTRACT FROM AUTHOR]

In order to obtain the accurate mechanical properties of 7075 aluminum alloy, the Gleeble-1500D thermal simulation test machine was used to perform compression test on 7075 aluminum alloy. The deformation temperature range is 490 °C~560 °C, and the strain rate is 0,001 s-1~1 s-1.At present, for the high temperature thermal compression process, the Arrhenius constitutive model with strain compensation is usually used. The results show that the correlation coefficient of the Arrhenius constitutive model of 7075 aluminum alloy with strain compensation is 0,9894, and the average relative error is 5,6 %, realizing the fitting of flow stress and prediction, verified the feasibility of the model. [ABSTRACT FROM AUTHOR]

In order to meet the requirements for the quality of steel structure welding projects in severe cold areas, reasonable and effective technical research and welding scheme improvement are carried out for welding in low temperature environments. Based on ABAQUS software to simulate different welding conditions, mainly for welding after traditional flame heating and ceramic sheet heating in low temperature environment, the corresponding temperature field is obtained. Compared with the actual welding results, it is concluded that the weldment welded after heating with ceramic sheet is of better quality, fully verify the accuracy of welding simulation, optimize process design, shorten the time required for practical inspection accumulation. [ABSTRACT FROM AUTHOR]

Q345C steel is welded under two different pre-welding heating methods of traditional flame heating and ceramic sheet heating. The finite element analysis of the butt joint weldment by ABAQUS software is used to summarize the law of welding deformation and compare the welding quality under different pre-welding heating methods according to the residual stress and deformation trend of the welding joint weld. The results show that the main stress after welding is concentrated in the weld seam and the surrounding area. The residual stress after welding after the heating and welding of the ceramic sheet is significantly less than the residual stress after the traditional flame heating welding, and the welding after the heating of the ceramic sheet can obtain better welding quality. [ABSTRACT FROM AUTHOR]

At the deformation temperature of 1 103-1 283 K, with strain rate of 0,01 - 10 s-1, and total strain of 0,7, the deformation behavior of TC6 titanium alloy was studied. The Arrhenius constitutive model is established by using stress - strain data when the strains of TC6 titanium alloy are 0,05, 0,1, 0,2, 0,3, 0,4, 0,5, 0,55, 0,6, and the accuracy of the model was verified. The results show that: the flow stress of TC6 titanium alloy increases as the strain rate increases and decreases as the deformation temperature increases; under different strains, the correlation coefficient (R) between the experimental value and the predicted value is greater than 98%, and the average relative error (AARE) is lower than 10%, which suggests that the established model has a higher prediction. [ABSTRACT FROM AUTHOR]

The hot compression test was conducted in Gleeble-1 500D to study the hot flow stress behavior of AA6 111 aluminum alloy belonging to Al-Mg-Si series, at the deformation temperatures ranging from 350 to 500 °C and strain rates ranging from 0,01 s-1 to 1 s-1. And how the flow stress change with variation of strain, temperature and strain rate was investigated. The results show that flow stress increases with decreasing temperature and increasing strain rate; the AA6 111 is positive stain rate sensitive material; the main softening mechanism is dynamic recovery. Furthermore, constitutive equation considering the effect of strain was obtained based on Arrhenius equation. The predicted flow stress values well agree with the experimental results with some little aberration. The coefficient of association can be as high as 0,9 954, which shows high reference value for industry and simulation analysis. [ABSTRACT FROM AUTHOR]