Steel Socket Pipe Conduit Cracked Next to Weld Seam

2019 ◽  
Keyword(s):  
Weld Seam

scholarly journals Influence of material degradation on weld seam quality in hot gas butt welding of polyamides

2021 ◽  
Author(s):  
Max Bialaschik ◽  
Volker Schöppner ◽  
Mirko Albrecht ◽  
Michael Gehde
Keyword(s):  
Weld Seam ◽  
Experimental Investigations ◽  
Heating Process ◽  
Butt Welding ◽  
Hot Gas ◽  
Process Gas ◽  
Glass Fiber Reinforced ◽  
Extrusion Welding ◽  
Different Gases

AbstractThe joining of plastics is required because component geometries are severely restricted in conventional manufacturing processes such as injection molding or extrusion. In addition to established processes such as hot plate welding, infrared welding, or vibration welding, hot gas butt welding is becoming more and more important industrially due to its advantages. The main benefits are the contactless heating process, the suitability for glass fiber reinforced, and high-temperature plastics as well as complex component geometries. However, various degradation phenomena can occur during the heating process used for economic reasons, due to the presence of oxygen in the air and to the high gas temperatures. In addition, the current patent situation suggests that welding with an oxidizing gas is not permissible depending on the material. On the other hand, however, there is experience from extrusion welding, with which long-term resistant weld seams can be produced using air. Investigations have shown that the same weld seam properties can be achieved with polypropylene using either air or nitrogen as the process gas. Experimental investigations have now been carried out on the suitability of different gases with regard to the weld seam quality when welding polyamides, which are generally regarded as more prone to oxidation. The results show that weld strengths are higher when nitrogen is used as process gas. However, equal weld strengths can be achieved with air and nitrogen when the material contains heat stabilizers.

Modeling and Analysis of Underwater Wet Weld Process Based on Regression Method

2013 ◽  
Vol 690-693 ◽  
pp. 2621-2624
Author(s):  
Bo Chen ◽  
Ji Cai Feng
Keyword(s):  
Weld Seam ◽  
Welding Process ◽  
Regression Method ◽  
Modeling And Analysis ◽  
Underwater Wet Welding ◽  
Underwater Environment ◽  
Arc Sensor ◽  
Weld Parameters ◽  
Automation Technology ◽  
Weld Automation

Underwater weld technology is urgently needed for the widely development of marine recourses, and weld automation technology is the inevitable choice because of the underwater environment. Because of the influence of the rigorous environment, the weld seam forming of underwater wet welding is very poor. To control the weld seam forming automatically, the model between the weld parameters and the weld seam shape must be built. This paper used arc sensor to monitor the electrical information of underwater wet welding process, and regression method was used to model the process, and the factors that influence the weld seam forming mostly were analyzed.

scholarly journals Effect of process parameters on longitudinal weld seam quality of aluminum alloy profile for an automobile fuel tank protector

2020 ◽  
Vol 50 ◽  
pp. 159-167
Author(s):  
Wenlin Chen ◽  
Chen Xu ◽  
Penglin Pan ◽  
Xiangming Ruan ◽  
Hongxuan Ji
Keyword(s):  
Aluminum Alloy ◽  
Process Parameters ◽  
Weld Seam ◽  
Fuel Tank ◽  
Longitudinal Weld Seam

Fatigue Crack Growth at Electrical Resistance Welding Seam of API 5L X-70 Steel Line Pipe at Varied Orientations

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Craig Taylor ◽  
Sreekanta Das ◽  
Laurie Collins ◽  
Muhammad Rashid
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Base Metal ◽  
Electrical Resistance ◽  
Weld Seam ◽  
Full Scale ◽  
Resistance Welding ◽  
Line Pipe ◽  
Full Scale Testing

Very few studies have been conducted concerning fatigue in steel line pipe and fewer using full-scale testing. Further, at the time of this study, no research on full-scale testing was available in open literature regarding fatigue behavior of line pipe with longitudinal cracks, despite being considered more critical than the line pipe with cracks oriented in the circumferential direction. In the current research work, fatigue crack growth was investigated in NPS 20, API 5L X-70 grade, electrical resistance welding (ERW) straight-seam steel line pipes in the base metal and at the weld seam for various orientations. It was found that there was no significant difference between fatigue crack growth in the base metal and at the weld seam for the tested stress ratio. Increasing the angle of inclination of the crack with respect to the weld line was found to decrease the rate of fatigue crack growth due to a decrease in the mode I stress component. Finally, it was observed that despite the difference in fatigue crack growth rates, the crack aspect ratios were nearly identical for all cracks at the same crack depth.

Evaluation of Repair Welding Influence on GH3535 Superalloy Microstructure and Mechanical Properties

2016 ◽  
Author(s):  
Chaowen Li ◽  
Shuangjian Chen ◽  
Kun Yu ◽  
Zhijun Li
Keyword(s):  
Mechanical Properties ◽  
Arc Welding ◽  
Weld Seam ◽  
Filler Metal ◽  
Short Term ◽  
Weld Repair ◽  
Repair Welding ◽  
Gas Tungsten Arc ◽  
Rolled Plates ◽  
Carbide Precipitate

GH3535 supperalloy, whose grade of ASME is UNS N10003, is currently considered as a candidate material for solid-fuel and fluid-fuel molten salt reactor in china. During the development of procedures for welding GH3535 superalloy, consideration should always be given to the possibility that repair welding may be necessary. This paper presents weld repairs of GH3535 alloy rolled plates using gas tungsten arc welding with filler metal. The purpose of this work is to evaluate the low heat input process for weld repair of GH3535 alloy plates about the microstructure features and mechanical properties. The results demonstrated that sound joints without defects could be obtained after weld repairs. Due to repair thermal cycles on the original weld seam, the size of carbide precipitate became large, but repair welding is found to cause no decrease in short-term time-independent strength.

The Use of Optimized ERW Technique to Improve Low Temperature Fracture Toughness of Welded Pipes

2020 ◽  
Author(s):  
Muhammad Rashid ◽  
Timothy Hylton ◽  
Neil Anderson ◽  
Laurie Collins ◽  
Leijun Li
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Low Temperature ◽  
Weld Seam ◽  
Peak Temperature ◽  
Line Pipe ◽  
Squeeze Pressure ◽  
Treatment Practices ◽  
Treatment Techniques ◽  
Research Activities

Abstract It is understood that the bondline microstructure of the line pipe ERW seam can be a zone of weakness in the pipe. To overcome this weakness, several research projects utilizing various line pipe steel grades and welding and heat treatment techniques have been conducted at EVRAZ NA. The overall goal of these efforts has been to understand the development of bondline microstructure during the ERW process and improve the weld seam fracture toughness for low temperature applications. These research activities included mill trials and Gleeble simulations. It was realized that a high toughness ERW weld seam is only possible through a tightly controlled combination of weld power, forging (squeeze) pressure, and welding speed. Research studies have indicated that the as-welded seam may not pass the standard ERW destructive tests if proper heat input and adequate squeeze pressure are not applied. Post weld heat treatment (normalizing) practice was also found to be a key element in the development of the appropriate bondline microstructure for higher toughness. Samples from pipes normalized using different heat treatment practices produced different bondline microstructures and hence different toughness properties. It was found through this study that a low (but still higher than the upper critical temperature Ac3) normalizing peak temperature and adequate soak time at the peak temperature result in improved Charpy toughness of ERW bondline microstructure.

Buckling Resistance of Large Diameter Spiral Welded Linepipe

2004 ◽  
Author(s):  
Tom Zimmerman ◽  
Chris Timms ◽  
Jueren Xie ◽  
James Asante
Keyword(s):  
Oil And Gas ◽  
Weld Seam ◽  
Large Diameter ◽  
Ground Movement ◽  
Finite Element Analyses ◽  
Line Pipe ◽  
Diameter Pipe ◽  
Buckling Resistance ◽  
Analytical Research ◽  
Full Scale Tests

This paper contains the results of an experimental and analytical research program to determine the compressive buckling resistance of large-diameter, spiral-welded linepipe. Buckling resistance is important for pipe intended for service in Arctic, oil and gas pipeline systems, where pipes may be subjected to high bending strains caused by various ground movement events. The experimental work consisted of four full-scale tests of 30-inch (762 mm) diameter pipe subjected to various combinations of internal pressure, axial force and bending. The pipe specimens were fabricated using two material grades (X70 and X80) and two D/t ratios (82 and 48). Finite element analyses of the four tests were conducted to develop a better understanding of specimen behavior. The results suggest that spiral welded linepipe is as good as longitudinally welded line pipe in terms of buckling capacity. The spiral weld seam was in no way detrimental to the pipe performance.

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