Stainless Steel Pipe Research Articles

Identifying the influence of orbital pipe welding parameters on mechanical properties using SS316L pipe

Pipeline systems play a pivotal role across various industries, serving as the lifelines for transporting materials like oil, water, and gas. Among the welding techniques, orbital pipe welding, particularly Gas Tungsten Arc Welding (GTAW) without filler metal, is the fitting method for joining these critical piping systems. This study examined orbital pipe welding on SS316L pipes with a 114-mm outer diameter and 3-mm thickness. The main goal was to evaluate the weld's tensile strength and microhardness carefully. Constant current and three welding speeds – 1.3, 1.4, and 1.5 mm/s – achieved this goal. In addition, welding experiments covered 0°, 90°, 180°, and 270° pipe positions. First, the necessary tools and test objects were prepared, and then the test materials were welded. The final phase was testing tensile strength and microhardness. This investigation used a 5G-specific prototype orbital pipe welding equipment. The 5G method requires horizontal welding with the vertical pipe axis. The study used ASTM E-8M-compliant standardized test material for precise and repeatable tensile strength measurements. This standardization ensured outcomes reliability. One of the significant findings was that 1.4 mm/s welding at the 270° pipe position with 110A current produced the maximum tensile strength. This shows that these conditions are best for welding SS316L-type stainless steel pipes with an outside diameter of 114 mm and a thickness of 3 mm. Strangely, microhardness testing showed that horizontal distribution welding quality decreased at 1.4 mm/s. This implies that further experimentation may be needed to fine-tune the welding parameters to optimize the process and achieve superior microhardness values.

Sampling, characterization, method validation, and lessons learned in analysis of highly activated stainless steel from reactor decommissioning

Characterisation of activated reactor components is a multifaceted effort, which include both experimental work and activation calculations which together form a comprehensive characterisation approach. However, both the experimental work and activation calculations have their constraints and uncertainties. This work presents the characterisation of a highly activated stainless steel pipe including sampling planning, sampling, sub-sampling, elemental and radionuclide analyses, and activation calculations. 55Fe, 63Ni and 60Co analyses were carried out in a trilateral intercomparison exercise and the results were compared with activation calculations. The results showed excellent alignment between experimental and activation calculation results.

Pushing boundaries in 3D printing: Economic pressure filament extruder for producing polymeric and polymer-ceramic filaments for 3D printers

3D printing technology can deliver tailored, bioactive, and biodegradable bone implants. However, producing the new, experimental material for a 3D printer could be the first and one of the most challenging steps of the whole bone implant 3D printing process. Production of polymeric and polymer-ceramic filaments involves using costly filament extruders and significantly consuming expensive medical-grade materials. Commercial extruders frequently require a large amount of raw material for experimental purposes, even for small quantities of filament. In our publication, we propose a simple system for pressure filament extruding, which allows obtaining up to 1-meter-long filament suitable for fused filament fabrication-type 3D printers, requiring only 30 g of material to begin work. Our device is based on stainless steel pipes used as a container for material, a basic electric heating system with a proportional–integral–derivative controller, and a pressurised air source with an air pressure regulator. We tested our device on various mixes of polylactide and polycaprolactone with β-tricalcium phosphate and demonstrated the possibility of screening production and testing of new materials for 3D-printed bone implants.

Investigation into the local continuous heating calibration process of a 304 stainless steel pipe by electrically assisted roll bending

A promising technology of the local continuous heating calibration process (LCHCP) was investigated by applying different parameters of electropulsing to the circumferential arc shell of a 304 stainless steel pipe during the roll bending process. In comparison to the cold calibration process, the roundness of the pre-deformed 304 stainless steel pipe was significantly improved by increasing the current density and the electropulsing width. The ring gaps in the characterization of the springback possessed a similar response to both the current density and the electropulsing width. Meanwhile, a stress relaxation constitutive model considering the electropulsing was employed to greatly fit the ring gaps.

Numerical investigation of effects of nickel-base alloy overlay size on the welding residual stresses in an austenite stainless steel narrow-gap girth weld

Based on the experimental measurement of the residual stress in the nickel-based alloy overlaid stainless-steel narrow-gap girth weld, an axisymmetric finite element (FE) model was established to simulate the residual stress in the girth weld to verify the model. Then a large number of numerical simulations were carried out with the verified FE model to study the effects of the size (height and length) of the nickel-based alloy weld overlay on the residual stress in the girth weld. The optimal overlay sizes to achieve sufficient depth of the compressive stress were investigated. The results show that as the overlay height increases, the hoop compressive stress depth from the inner wall at the weld centerline increases, while the range of the axial compressive stress distribution decreases. The hoop and axial compressive stress depths at the weld centerline increase as the overlay width increases, while the depth of the hoop compressive stress remains unchanged when the overlay width reaches a critical value. The effect of the overlay height on the hoop stress is greater than that of the overlay width, and it is more difficult to mitigate the axial stress by increasing the width of the overlay layer with a large overlay height. For the narrow-gap 304 stainless-steel pipe girth weld with a size of Ø273 mm × 28 mm, the optimum nickel-based alloy overlay is 14 mm in height and 210 mm in width, which can cause both hoop and axial stresses at the inner wall to be compressive, and the hoop compressive stress depth from the inner wall reaches 88 % of the pipe wall thickness and axial compressive stress depth reaches 78 % of the wall thickness.

Lifespan Estimation of Galvanized Steel and Stainless Steel Pipe

Lifespan Estimation of Galvanized Steel and Stainless Steel Pipe

Investigations of Weldment Joints of Exhaust Pipes Using Non-Destructive Testing (NDT)

Exhaust pipe components are especially vulnerable to accelerated degradation. Cracks are identified during the scheduled inspection and repaired by weld-filling procedure or by more invasive approaches like cutting and replacing sections. Such small defects can develop into fatigue or stress corrosion cracks in service, which can be extremely difficult to detect. The input parameter has a significant impact on weldment joint quality. Welds are checked to determine whether or not they meet specifications. The study was carried out to inspect and assess the quality of the weldment joints of exhaust pipes using non-destructive testing (NDT). An experimental approach methodology was adopted to achieve the aim of the study. Specimens of car exhaust pipes were welded and tested using some selected non-destructive testing techniques. Six (6) samples were selected for testing, with a serious fault or discontinuity in the artisan-made welded seam. The results showed that the principal fault signs were lack of fusion, surface porosity, crater fractures, linear indication, and undercuts, all of which were below the allowable standards of the AMSE B31.3 Stainless-Steel pipe code and therefore must be rejected.

Investigation of pipelines defect localization for fusion reactor by using T(0,1) mode ultrasonic guided waves

The stable operation of a fusion reactor depends on the reliable functioning of various accessory systems, many of which comprise extensive pipelines with different diameters and diverse cladding. Defects in pipelines can occur due to manufacture, thermal stress, and fatigue, threatening the systems’ safety and reliability. Ultrasonic guided waves (UGWs) testing offers a promising approach for remotely locating these minute defects. The study explores non-dispersive fundamental torsional guided (T(0,1)) waves, particularly their influence on minor defect detection in stainless steel pipes. Both finite element simulations and experimental trials reveal that reflection coefficients, indicative of defect presence, rapidly escalate from 64 to 128 kHz. The optimal frequency for minor defect detection lies between 128 and 180 kHz. A significant finding from the circumferential distribution spectrum and angle profile reveals pipe diameter's dominant influence on the reflection energy distribution concentration. Furthermore, this highlights the unique ability of T(0,1) guided waves to precisely locate defects in the circumferential direction within large-diameter pipes over long distances. The results underscore the promising potential of UGWs testing in complex pipelines of fusion reactors.

Experimental study of liquid/dense-gas pipe flow

The pre-salt reservoirs play a significant role in the current Brazilian ultradeep water offshore scenario. Their importance is expected to increase soon. The fluids are transported through horizontal, inclined, and vertical wells of several kilometers, and due to the environmental conditions at the reservoir, dense-gas/liquid flow occurs in the pipelines. However, the literature lacks experimental data for gas-liquid flow with densities of the same order of magnitude, which affects the mechanistic model's accuracy for flow patterns, pressure gradients, and holdup predictions. To improve the understanding of that specific two-phase flow, an experimental apparatus was built, and an experimental study was carried out using sulfur hexafluoride (100 kg/m3) and mineral oil (850 kg/m3) at medium pressures. A density ratio lower than 10 was obtained for steady-state horizontal flow in a 50.8-mm-i.d. stainless-steel pipe, and flow patterns, pressure gradient, and holdup were measured. The experimental results show the effect of the low-density ratio on the stratified to non-stratified flow-pattern transition and the occurrence of the dual-continuous flow pattern at high mixture superficial velocity. Moreover, the pressure gradient and holdup data were compared with the results of a commercial multiphase flow simulator, showing good agreement.

Removal of SUS304 fine particles transformed into martensite by the high gradient magnetic separation under dry condition

The interfusion of impurities such as metallic wear debris has been a major issue in the manufacturing process of foods, medicines and industrial products. Such debris originates with wearing of stainless-steel pipe joints or mechanical moving parts. Since the debris shows ferromagnetic properties by undergoing the strain-induced martensitic transformation of non-magnetic SUS304 (X5CrNi18-10), the magnetic separation system is much efficient to remove such debris from raw materials. In order to study the magnetic separation properties for the martensitic transformation fine particles, the several kinds of magnetic powder with different magnetization were prepared by controlling the amount of martensitic transformation by heat-treating SUS304 powders. The magnetic separation performance was evaluated by the high gradient magnetic separation (HGMS) experiments using the multilayer unidirectional magnetic wire filter under dry condition. The experimental results and FEM particle trajectory simulations revealed that the SUS304 powders transformed into martensite were removed at high speed of 0.1 m/s by the superconducting HGMS in a relatively low magnetic field.

Testing of Carbon Steel Pipe and Stainless Steel Duplex Pipes of Welding Joints : A Cost and Time Perspective

In the welding process, it is not uncommon for a defect or discontinuity to occur in the welding results. Common defects on the surface are undercut, concavity, incomplete penetration, spatter, burn-through, and mismatch. While defects in internal welds that are often found during testing are porosity, worm holes, slag inclusions, incomplete fusion, and cracks, To obtain pipeline results that comply with the specifications set by the welding engineer and ASME or ASTM standards, it is necessary to test surface cracks and inside cracks using the non-destructive test (NDT) method, namely the dye penetrant test and radiography test, to determine the results of welding at pipe joints. In addition, it is also necessary to know the time and cost required for each method in the testing process. The results of the radiography test and penetrant test on carbon steel pipe welding joints showed porosity welding defects 1 mm long. Weld defects in duplex stainless steel pipes were not found. Then the results of the total testing time using the radiography test take 18% longer than testing using the penetrant test. Furthermore, the total costs that need to be incurred during the test are found to be 2~3 times more expensive than the cost of the penetrant test.

Experimental study on 3D printed heat pipes with hybrid screen–groove combined capillary wick structure

The integration of heat pipes as a passive thermal management system for nuclear reactors has been proposed as it provides the advantages of compact design, reliability, efficient heat transfer performance, and enhanced safety. Applying the heat pipe to a nuclear reactor without collision between systems and achieving efficient long-distance heat transfer requires the manufacturing of heat pipes with a high degree of freedom. Using three-dimensional (3D)-printing technology can be a solution for fabricating complex or bent capillary wick heat pipes into an integrated geometry. The study involves the production of a heat pipe using metal 3D-printing technology and an experimental study conducted for thermal performance evaluation. The heat pipe includes a combination of a screen-groove wick in the evaporator section, a groove wick in the adiabatic and condenser sections, and a bent wick structure in the middle. By using 3D printing technology, it is possible to create a heat pipe that has a complex wick design, a consistent porous structure and remains undistorted during the manufacturing process. The surface roughness of the 3D-printed heat pipe was 17 to 1700 times higher than the commercial stainless-steel pipe, which has the benefit for enhance capillary performance. The experimental results showed that the 3D-printed heat pipe can achieve high effective thermal conductivity up to 25.7 kW/m-K and showed 24.2% lower thermal resistance compared to the conventionally manufactured heat pipe. Furthermore, it can be successfully operated at various inclination angles.

Design of type 316L stainless steel 700 °C high-temperature piping

High-temperature design evaluations were conducted on Type 316L stainless steel piping for a 700 °C large-capacity thermal energy storage verification test loop (TESET) under construction at KAERI. The hot leg piping with sodium coolant at 700 °C connects the main components of the loop heater, hot storage tank, and air-to-sodium heat exchanger. Currently, the design rules of ASME B31.1 and RCC-MRx provide design procedures for high-temperature piping in the creep range for Type 316L stainless steel. However, the design material properties around 700 °C are not available in those rules. Therefore, a number of material tests, including creep tests at various temperatures, were conducted to determine the insufficient material properties and relevant design coefficients so that high-temperature design on the 700 °C piping may be possible. It was shown that Type 316L stainless steel can be used in a 700 °C high-temperature piping system of Generation IV reactor systems or a renewable energy systems, such as thermal energy storage systems, for a limited operation time.

Preliminary exploration of the electrical insulation performance of APPJ SiO2 coating on 304 stainless steel pipes

The atmospheric pressure plasma jet (APPJ) technique is used to prepare SiO2 insulation coatings onto the outer surface of 304 stainless steel pipes (304-SSPs). The diameter and surface roughness of 304-SSPs increase from 18 to 32 mm and 0.1 to 1.0 μm. The results show that APPJ scanning methods have little influence on the chemical composition, chemical bond structure, crystal structure, and surface morphology of SiO2 coatings, which display Si/O = 1/(1.95 ± 0.02), dominant Si-O bond, amorphous structure, and dense layer structure. However, APPJ scanning methods have obvious influence on the uniformity and electrical insulation resistance (REI) of SiO2 coatings. Only when APPJ is parallel to the normal direction of 304-SSPs outer surface, the balance between APPJ impingement, gravity, and coating surface tension could reach the optimal condition, which improves the uniformity and REI of SiO2 coatings. With the optimal scanning method, REI of SiO2 coatings decrease with the increase of surface roughness of 304-SSPs, which are caused by the decrease of effective thickness of SiO2 coatings. Most importantly, with the other parameters as constant, REI of SiO2 coatings reaches to ∼101 MΩ and displays the better uniformity when the diameter of 304-SSPs is about 5 times the diameter of APPJ tube.

Optimization of gas tungsten arc welding parameters for welding of super duplex stainless steel using factorial design

This study investigates the relationship between four welding input parameters (voltage, current, heat input, and welding speed) and the ultimate tensile strength (UTS) and yield strength (YS) of a welded joint. The work joined two super-duplex stainless-steel pipes of outside diameter 0.630 inches (16.002 mm) and a thickness of 0.065 (1.651 mm), using Gas Tungsten Arc Welding. Factorial design was used to ascertain the main and interaction effects of the welding input parameters on the UTS and YS of the welded joint. Results revealed a significant interaction between voltage, current, welding speed and heat input for UTS, and a significant interaction between the welding speed and heat input for YS. Results further revealed that as voltage increases from 9.3 V to 11.6 V, the UTS decreases by 2.69 MPa, while YS increases significantly by 24.25 MPa. When the current increases from 30 A to 38 A, the UTS increases by 10.81 MPa, while the YS increases by 4.25 MPa. In the case of the welding speed, an increase from 0.46 to 0.71 mm/s results in a decrease of the UTS by 7.94 MPa and a significant increase of the YS by 33.25 MPa. When the heat input increases from 0.54 to 0.70 kJ/mm, the UTS decreases by 15.06 MPa, whereas the YS decreases significantly by 35.25 MPa. Also, the optimum voltage, current, welding speed and heat input for UTS are 11.60 V, 30.0 A, 0.71 mm/s, and 0.70 kJ/mm, respectively, and those of YS are 9.30 V, 30.0 A, 0.46 mm/s, and 0.70 kJ/mm, respectively.

Investigating the effects of defects and the effect of geometric anisotropy in stainless steel pipes: phased array ultrasonic test, SH-wave

Today, Phased Array Ultrasonic Testing (PAUT) is a suitable method for detecting defects in Non-destructive Testing (NDT). This simulation was done with a new method on a stainless steel pipe with a diameter of 500 mm and a length of 1,000 mm, and cracks were modeled on the external and internal surfaces and corrosion defects on the internal surface. Four probes with a characteristic of 2 MHz were used simultaneously, each probe having 64 elements. By increasing the number of probes and their elements, more accurate information about the defects is obtained, which makes it easier to detect the location and leads to a reduction of scattered signals and noise, which can detect even small size defects. Considering this important advantage, a new use of the method of increasing the number of probes in PAUT is reported in this study to detect defects, especially corrosion defects. The results of geometric anisotropy studies of group velocity and phase of horizontally polarized shear waves (SH-waves) for stainless steel pipe were presented. Due to the isotropic properties of the pipe material, the speed on the outer surface of the pipe in the direction of the cover is 40 m/s higher than the generatrix.

Study on heat transfer performance using ceramic membrane to recover moisture and waste heat from flue gas

The release of industrial flue gas into the environment leads to a significant waste of latent heat and water resources. To address this issue, the transmission membrane condenser (TMC) has emerged as a promising technology. However, research on TMC is still in its early stages, lacking performance evaluation of heat exchangers and analysis of heat and mass coupling effects. This paper presents experiments conducted to assess the heat transfer performance of TMC at different undercooling degrees and flue gas velocities. A comparison between TMC and 316L stainless steel pipe is made to identify the impact factors of heat and mass coupling effects in TMC. The study also derives a Nusselt formula suitable for single-channel ceramic membranes, providing theoretical guidance for their application.

High-performance fixed-bed in situ mass analyzer-ISMA.

We demonstrate a newly developed high-performance fixed-bed reactor combined with an in situ mass analyzer (ISMA). The ISMA is particularly relevant to sub-second time-resolved studies where mass changes occur due to, e.g., chemical reactions and process conditions such as choice of solid, temperature, gas atmosphere, and pressure. The mass is determined from the optically measured oscillation frequency of a quartz element, yielding a mass resolution below 10 μg-typically 2-3 μg-for samples up to ∼500 mg. By placing the quartz element and optical sensor inside stainless steel pipes and providing heat from the outside, the instrument is applicable up to ∼62 bars and 700°C. By surrounding this core part of the instrument with a suitable feed system and product analysis instruments, in combination with computer control and logging, time-resolved studies are enabled. The instrument with surrounding feed and product analysis infrastructure is fully automated. Emphasis has been put on making the instrument robust, safe, operationally simple, and user-friendly. We demonstrate the ISMA instrument on selected samples.

Phased Array Ultrasonic Testing of Stainless Steel Pipe Welds

Weld inspection of stainless steel pipes and pressure vessels is one of the most challenging and difficult inspections for ultrasonic testing. This is due to variations in grain structure and associated anisotropy. Anisotropy causes grain scattering and adversely affects propagation of sound waves. The effect is more telling for shear waves, which, in many cases, have almost no ability to penetrate the weld volume. Longitudinal waves are affected to a lesser degree by anisotropy and can be applied for such tests. Angle beam or refracted longitudinal waves are, therefore, the accepted method for stainless steel weld inspections.

Numerical study on the flow and heat transfer of molten salt in a horizontal pipe applied transverse magnetic field

Based on a modification of a magnetohydrodynamic turbulence model, a numerical study was performed to investigate the effects of transverse uniform and gradient magnetic field on the turbulent flow and heat transfer characteristics of a low melting point molten salt in a stainless steel pipe. With the Hartmann number from 0 to 80, the numerical results showed that the fluid flow displayed anisotropic distributions under the magnetic field with decrease of velocity in the mainstream region, and decrease of turbulent intensity, whereas the flow velocity increased in the boundary layer near the Hartmann and Roberts wall. Especially, a velocity jet phenomenon was observed in the Roberts boundary layers at higher Hartmann number in the uniform magnetic field or the positive gradient magnetic field. Under the gradient magnetic field, the flow and heat transfer of molten salt displayed much more variations than under the uniform magnetic field. The magnetohydrodynamic calculation results proposed here might be helpful to the design of the composite heat transfer system for molten salt in actual industrial applications.