Numerical and Experimental Analysis of Dissimilar Repair Welding Residual Stress in P91 Steel Considering Solid-State Phase Transformation

2019 ◽  
Vol 28 (9) ◽  
pp. 5734-5748 ◽  
Author(s):  
Guoxiang Xu ◽  
Qinghu Guo ◽  
Qingxian Hu ◽  
Haichao Pan ◽  
Hongwei Qian ◽  
...  
Author(s):  
Dean Deng ◽  
Hidekazu Murakawa

In this study, an advanced computational approach based on SYSWELD software was developed to simulate welding residual stress distributions in P92 steel joints with the consideration of solid-state phase transformation. Using the developed numerical method, we calculated the welding residual stress distribution in a single-pass weld joint, and clarified the influences of volume change, variation of yield strength and phase transformation induced plasticity on the formation of residual stress. Meanwhile, experiment was carried out to measure the welding residual stress distributions in the single-pass joint. The effectiveness of the developed computational approach was verified by the experimental results. In addition, the features of welding residual stress distribution in multi-pass P92 steel joint were discussed based on the results obtained by numerical simulation, and some new viewpoints on welding residual stress in multi-pass P92 steel joints were obtained.


Author(s):  
Mike C. Smith ◽  
Steve Bate ◽  
P. John Bouchard

Finite element methods are used increasingly to predict weld residual stresses. This is a relatively complex use of the finite element method, and it is important that its practitioners are able to demonstrate their ability to produce accurate predictions. Extensively characterised benchmark problems are a vital tool in achieving this. However, existing benchmarks are relatively complex and not suitable for analysis by novice weld modellers. This paper describes two benchmarks based upon a simple beam specimen with a single autogenous weld bead laid along its top edge. This geometry may be analysed using either 3D or 2D FE models and employing either block-dumped or moving heat source techniques. The first, simpler, benchmark is manufactured from AISI 316 steel, which does not undergo solid state phase transformation, while the second, more complex, benchmark is manufactured from SA508 Cl 3 steel, which undergoes solid state phase transformation during welding. A number of such beams were manufactured using an automated TIG process, and instrumented with thermocouples and strain gauges to record the transient temperature and strain response during welding. The resulting residual stresses were measured using diverse techniques, and showed markedly different distributions in the austenitic and ferritic beams. The paper presents the information necessary to perform and validate finite element weld residual stress simulations in both the simple austenitic beam and the more complex ferritic beam, and provides performance measures for the austenitic beam problem.


Author(s):  
A H Yaghi ◽  
T H Hyde ◽  
A A Becker ◽  
W Sun

The methodology of numerically simulating residual stresses in a welded P91 pipe section is described. The finite element (FE) method has been applied to simulate residual axial and hoop stresses generated in the weld region and heat affected zone (HAZ) of an axisymmetric 50-bead circumferentially butt-welded P91 steel pipe, with outer diameter of 145 mm and wall thickness of 50mm. The FE simulation consists of a thermal analysis which is followed by a sequentially-coupled structural analysis. Solid-state phase transformation (SSPT), which is characteristic of P91 steel during welding thermal cycles, has been modelled in the FE analysis by allowing for volumetric changes in steel and associated changes in yield stress due to austenitic and martensitic transformations. Phase transformation plasticity has also been taken into account. Preheat and interpass temperature control has been included in the modelling process. Thermally-obtained temperature contours indicate the size of the weld region, parent metal penetration, and HAZ. Residual axial and hoop stresses have been depicted through the pipe wall thickness as well as along the outer surface of the pipe. The results indicate the importance of including SSPT in the simulation of stresses during the welding of P91 steel.


2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940046
Author(s):  
Z. Zhu ◽  
B. Chen ◽  
G. Gou ◽  
Z. Zhang ◽  
C. Ma ◽  
...  

The coupling model of temperature-phase transformation-mechanics is constructed in this paper. The effect of solid state phase transformation and different hardening models on the residual stress distribution of S355J2W welded joints have been studied with finite element method (FEM) simulation. The microstructure, micro hardness and residual stress of welded joints are also studied. It has been shown that the microstructure of weld seam is composed of bainite structure with little martensite, while the base metal is ferrites and pearlites. The simulation results by FEM were in good accordance with the X-ray results. The maximum tensile residual stress is 463 MPa in the weld. The tensile residual stress was decreased with the larger distance to the weld.


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