Effect of Impact Pressure on Reducing the Weld Residual Stress by Water Jet Peening in Repair Weld to 304 Stainless Steel Clad Plate

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Wenchun Jiang ◽  
Yun Luo ◽  
Huai Wang ◽  
B. Y. Wang
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Moving Load ◽  
Water Jet ◽  
Impact Pressure ◽  
304 Stainless Steel ◽  
Tensile Stresses ◽  
Compressive Stresses ◽  
Stainless Steel Clad Plate

Stainless steel clad plate manufactured by explosive bonding is widely used in the chemical industry, but cracks are often initiated in the clad layer. Repair welding is a popular method to repair the cracked zone. But residual stresses are generated inevitably, which can lead to further cracking. How to decrease the residual stress is critical to ensure the structure integrity. This paper studies a method to reduce weld residual stresses by water jet peening (WJP) in 304 stainless steel clad plate. The effect of impact pressure is discussed. A sequential coupling finite element method is developed to simulate the as-welded residual stresses, which is validated by impact indentation measurement. Then, a user subroutine is developed to model the moving load generated by WJP. The results show that the WJP can introduce compressive stresses on the metal surface and thus decrease the as-welded tensile stresses. As the maximum impact pressure at the center of impact (P0) increases, the residual stresses are decreased greatly and even change to compressive stresses. There is a critical value P0, which changes the tensile stresses to compressive stresses. As P0 increases to 1.4 times the yield strength of 304 stainless steel, the initial tensile stresses on the surface have been decreased to compressive stresses.

scholarly journals Residual Stresses Induced by Surface Working and Their Improvement by Emery Paper Polishing

2020 ◽  
Vol 4 (2) ◽  
pp. 21
Author(s):  
Makoto Hayashi
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Diffraction Method ◽  
304 Stainless Steel ◽  
Heat Treated ◽  
Emery Paper ◽  
Type 304 ◽  
Type 304 Stainless Steel

In many of machine parts and structural components, materials surface would be worked. In this study, residual stresses on the surfaces were measured by X-ray diffraction method, and effects of surface working on the residual stresses were examined. In case of lathe machining of type 304 stainless steel bar, the residual stresses in circumferential directions are tensile, and those in axial directions are almost compressive. Highly tensile residual stresses in the circumferential directions were improved by emery paper polishing. 10 to 20 times of polishing changes high tensile residual stresses to compressive residual stresses. In the case of shot peening on a type 304 stainless steel plate, the compressive residual stress inside is several hundred MPa lower than that on the surface. By applying the emery paper polishing to the shot peened surface 10 or 20 times, the residual stress on the surface is improved to −700 MPa. While fatigue strength at 288 °C in the air of the shot peened material is 30 MPa higher than solution heat treated and electro-polished material, the fatigue strength of the shot peened and followed by emery paper polished material is 60 MPa higher. Thus, the emery paper polishing is simple and a very effective process for improvement of the residual stresses.

Residual Stresses Prediction for CO2 Laser Butt-Welding of 304-Stainless Steel

2006 ◽  
Vol 3-4 ◽  
pp. 125-130 ◽  
Author(s):  
Khaled Y. Benyounis ◽  
Abdul Ghani Olabi ◽  
M.S.J. Hashmi
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Laser Power ◽  
Travel Speed ◽  
304 Stainless Steel ◽  
Hole Drilling ◽  
Design Matrix ◽  
Butt Welding ◽  
Input Variables

Residual stresses are an integral part of the total stress acting on any component in service. It is important to determine and/or predict the magnitude, nature and direction of the residual stress to estimate the life of important engineering parts, particularly welded components. This work aims to introduce experimental models to predict residual stresses in the heat-affected zone (HAZ). These models specify the effect of laser welding input parameters on maximum residual stress and its direction. The process input variables considered in this study are laser power (1.03 - 1.368 kW), travel speed (26.48 – 68.52 cm/min) and focal point position (- 1 to 0 mm). Laser butt-welding of 304 stainless steel plates of 3 mm thick were investigated using a 1.5 kW CW CO2 Rofin laser as a welding source. Hole-drilling method was employed to measure the magnitude, and direction of the maximum principal stress in and around the HAZ, using a CEA-06- 062UM-120 strain gauge rosette, which allows measurement of the residual stresses close to the weld bead. The experiment was designed based on Response Surface Methodology (RSM). Fifteen different welding conditions plus 5 repeat tests were carried out based on the design matrix. Maximum principal residual stresses and their directions were calculated for the twenty samples. The stepwise regression method was selected using Design-expert software to fit the experimental responses to a second order polynomial. Sequential F test and other adequacy measures were then used to check the models adequacy. The experimental results indicate that the proposed mathematical models could adequately describe the residual stress within the limits of the factors being studied. Using the models developed, the main and interaction effect of the process input variables on the two responses were determined quantitatively and presented graphically. It is observed that the travel speed and laser power are the main factors affecting the behavior of the residual stress. It is recommended to use the models to find the optimal combination of welding conditions that lead to minimum distortion.

Effect of Temperature on Strength and Residual Stress Distribution in Silicon Nitride to 304 Stainless Steel Brazed Joints

2004 ◽  
Vol 449-452 ◽  
pp. 881-884 ◽  
Author(s):  
Do Won Seo ◽  
Ho Chel Yoon ◽  
Jin Yi Lee ◽  
Jae Kyoo Lim
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
High Temperature ◽  
Silicon Nitride ◽  
Residual Stresses ◽  
Bending Strength ◽  
304 Stainless Steel ◽  
Effect Of Temperature ◽  
High Temperature Strength ◽  
Mechanical And Thermal Properties

Ceramics are significantly used in many industrial applications due to their excellent mechanical and thermal properties such as high temperature strength, low density, high hardness, low thermal expansion and good corrosion properties. To combine the specific advantages of ceramics with that of metals, they are often used together within one composite component. In this study, the effect of temperature on fracture characteristics of silicon nitride joined to 304 stainless steel brazed with Ti active alloy are investigated in room and high temperature regions. And analytical studies on the residual stress of dissimilar brazed joint are performed by the finite element method. Four-point bending strength and deflection of interlayer increase with increasing strain rate in room temperature. As the test temperature increases, the bending strength decreases, but the deflection of interlayer is almost constant. The residual stresses redistribute after cutting of joint and the maximum tensile stress occurs on the new free surface at the ceramic near the interface. The singularity of residual stresses at the ceramic near the interface is characterized by elastic-plastic properties of ceramic and inserted materials.­

Residual Stress Simulation in Multi-Pass Weld of Stainless Steel Pipes

2012 ◽  
Vol 578 ◽  
pp. 82-86 ◽  
Author(s):  
Long Shi Gao
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Mechanical Analysis ◽  
304 Stainless Steel ◽  
The Finite Element Method ◽  
Steel Pipes ◽  
Integrity Assessment ◽  
Temperature Distributions ◽  
Stress Simulation

Multi-pass welds are used in pipes with stainless steel. The complicated temperature field and residual stresses in these welded structures are very important. The finite element method is used to simulate residual stress in multi-pass butt-welds in this paper. Element birth technique is implemented to model multi-pass welded 304 Stainless Steel Pipes. One-way coupled Thermo-mechanical analysis is adopted to calculate the residual stresses, that the structural analysis takes the temperature distributions as thermal input. The results provide reference for the structure integrity assessment of welded pipes.

Residual Stress Generation and Relaxation in Butt-Welded Pipes

1982 ◽  
Vol 104 (3) ◽  
pp. 188-192 ◽  
Author(s):  
S. Nair ◽  
E. Pang ◽  
R. C. Dix
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Numerical Scheme ◽  
Stress Generation ◽  
304 Stainless Steel ◽  
Thermally Induced ◽  
Steel Pipes

A numerical scheme for the determination of thermally induced local residual stresses and their relaxation behavior during heat treatment in the case of butt-welded pipes is described. The procedure is illustrated by considering 304 stainless steel and SAE 1020 steel pipes. The results are compared with available experimental and numerical results.

Curvature Testing the Residual Stresses in 3%TiO2-Al2O3 Coatings by Thermal Spraying Technology

2011 ◽  
Vol 314-316 ◽  
pp. 48-52
Author(s):  
Fang Mei ◽  
Man Feng Gong
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Thermal Spraying ◽  
Minimum Value ◽  
Compressive Stresses ◽  
Different Thickness

Plasma thermal spraying technique was adopted to deposit five groups of different thickness 3% TiO2-Al2O3 coatings on 329-Stainless steel. A curvature method was applied to study the residual stresses. Results showed that the deformations corresponding to 3% TiO2-Al2O3/329-SS systems were serious. The residual stress changed with the ξ (ratio of coatings’ thickness to substrate’s thickness) value and weren’t constants for the coatings’ thickness 52-306 μm. No regardless of using the Stoney’ or Tomanov’ formula to calculate the residual stresses, which decreased with the ratio ξ value increased, and the thinner coatings were, the greater the residual stresses were. The coatings’ residual stresses changed with the ξ value at an exponent relation. The coatings’ thickness affects greatly on their residual stresses, especially for the intrinsic stresses. When the coatings thickness changes from 52 to 306 μm, the residual stresses were always compressive stresses. The maximums residual stresses were caused when the ξ value is 0.115 (the minimum value), and the details were -584.96 MPa and -482.78 MPa by two difference formulas, respectively.

scholarly journals Component residual stress control in forward rod extrusion by material flow and tribology—experiments and modeling

2021 ◽  
Author(s):  
A. Jobst ◽  
D. Floros ◽  
P. Steinmann ◽  
M. Merklein
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Material Flow ◽  
Opening Angle ◽  
Lubrication System ◽  
Near Surface ◽  
Tensile Stresses ◽  
Stress Control ◽  
Residual Stress State ◽  
Compressive Stresses

AbstractThe forward rod extrusion of ferritic stainless steel X6Cr17 (DIN 1.4016) is here investigated with the objectives to experimentally identify and numerically verify the effect of the lubrication system and die opening angle on residual stresses. Three lubricants – MoS2, soap and polymer – are considered whose tribological properties are characterized via double cup extrusion tests. The effect of material flow is also studied by forming in conical dies featuring three different opening angles. The extrusion experiments revealed a decrease in the near-surface tensile stresses with decreasing friction for all the considered opening angles. An opening angle of 2α = 90° led to the highest tensile residual stresses. Both an increase to 2α = 120° and a decrease to 60° resulted in reduced tensile stresses and even a shift to compressive stresses.Furthermore, a previously developed numerical model of forward rod extrusion is optimized and validated against the experimentally measured residual stresses. The effect of the spatial and temporal discretizations of the model on the predicted residual stresses is investigated. Based on the experimental and numerically verified results, the recommendation to reduce friction in forward rod extrusion is derived as a means to obtain a less detrimental to the lifecycle of extruded parts residual stress state.

Residual Stress Generation and Relaxation in Butt-Welded Pipes

1982 ◽  
Vol 104 (1) ◽  
pp. 42-46 ◽  
Author(s):  
S. Nair ◽  
E. Pang ◽  
R. C. Dix
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Numerical Scheme ◽  
Stress Generation ◽  
304 Stainless Steel ◽  
Thermally Induced ◽  
Steel Pipes

A numerical scheme for the determination of thermally induced local residual stresses and their relaxation behavior during heat treatment in the case of butt-welded pipes is described. The procedure is illustrated by considering 304 stainless steel and SAE 1020 steel pipes. The results are compared with available experimental and numerical results.

Measurement of Residual Stresses in Stainless Steel Cladded Specimens

2010 ◽  
Author(s):  
E. Kingston ◽  
M. Udagawa ◽  
J. Katsuyama ◽  
K. Onizawa ◽  
D. J. Smith
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Steel Substrate ◽  
Single Layer ◽  
304 Stainless Steel ◽  
Hole Drilling ◽  
Stress Distributions ◽  
Compressive Stresses ◽  
Three Samples ◽  
Type 304

Residual stresses were measured in cladded steel specimens using deep hole drilling (DHD) and block removal and surface layering (BRSL) techniques. The samples consisted of a A533B steel substrate and cladded with Type 304 stainless steel using two different welding techniques; electro-slag (ESW) and submerged welding (SAW). Two SAW samples were created; one with a single layer of weld and a second with a double layer of welding. Only a single weld layer of ESW was used on another sample. All three samples were subjected to post-weld heat treatment prior to measurement. The measured residual stress distributions revealed (as expected) tensile stresses in the clad. However, the DHD method measured compressive stresses in the substrate adjacent to the clad for the single layer ESW and SAW welds. In contrast, the BRSL method found that the residual stresses in the substrate were close to zero or approximately tensile. The measurements are compared with results obtained from finite element (FE) simulations of the welding and PWHT treatment. The predicted tensile residual stresses in the clad were found to be larger than the measurements while in the substrate the FE analysis did not predict the measured compressive stresses.

Effects of Clad and Base Metal Thickness on Residual Stress in the Repair Weld of a Stainless Steel Clad Plate

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Wenchun Jiang ◽  
B. Yang ◽  
J. M. Gong ◽  
S. T. Tu
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Weld Metal ◽  
Base Metal ◽  
Constraint Function ◽  
Thickness Increase ◽  
Metal Thickness ◽  
Stainless Steel Clad Plate

This paper used finite element method (FEM) to predict the residual stresses in repair weld of a stainless steel clad plate. The effects of clad metal thickness and base metal thickness on residual stresses have been investigated. The results show that large residual stresses have been generated in weld metal and heat affected zone (HAZ). The clad metal and base metal thickness have a great effect on residual stresses. With clad metal thickness increase, the deformation and plastic strain are increased to relax some residual stress, which leads to a decrease in residual stress. The repair structure has an angular deformation for the shrinkage of weld metal. The strength of base metal is great larger than that of clad metal, and therefore, the base metal has a constraint on the shrinkage of clad metal. As the base metal thickness increase, this constraint function is enhanced, which leads to an increase in residual stress, which provides a reference for the repair welding of stainless steel clad plate.

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