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 Effect of post-fabrication treatments on surface residual stresses of additive manufactured stainless steel 316L

2021 ◽  
Vol 49 (1) ◽  
pp. 87-94
Author(s):  
Kumar Barath ◽  
K.M. Aravindan ◽  
Jebaraj Vinoth ◽  
Kumar Sampath
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Homogeneous Distribution ◽  
Stainless Steel 316L ◽  
Compressive Stresses ◽  
Surface Residual Stresses ◽  
Laser Heat Source ◽  
Steel Aisi ◽  
Stainless Steel Aisi

In this work, an investigation was made to analyze the surface residual stresses on additive manufactured stainless steel AISI 316L in as-built and post-treated conditions. Direct metal laser sintering was used to fabricate the metal blocks. X-ray residual stress analysis on the as-fabricated surface revealed the presence of an inhomogeneous and irregular distribution of residual stresses in the as-built condition ranging from - 30 MPa to 111 MPa. It was mainly due to the localized laser heat source that caused variations in stresses at a lattice level. Heat treatment was performed for providing relief to the residual stress from the as-built condition showed significant relief of residual stress, which was lesser than 50% compared to as-built condition. Beneficial compressive residual stress induced by shot peening and lapping resulted in high magnitude compressive stresses on the surface. Also, homogeneous distribution of residual stress was found on the peened and lapped surface layer with an average of - 531 MPa and - 554 MPa, respectively.

Superficial Residual Stresses in Face-Milling the 17-4PH Stainless Steel at Various Feed Rates

2016 ◽  
Vol 693 ◽  
pp. 922-927 ◽  
Author(s):  
Guo Liang Liu ◽  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Jun Wang ◽  
Xiang Yu Wang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Feed Rate ◽  
Cutting Parameters ◽  
Face Milling ◽  
Stress Tests ◽  
Machined Surface ◽  
Compressive Stresses ◽  
Coated Carbide

17-4PH stainless steel is a widely used martensitic precipitation hardening stainless steel, and it is a typical difficult-to-cut material. Residual stress is an important part of the surface integrity. In this paper, superficial residual stress tests of face-milling the 17-4PH stainless steel were carried out at 0.1~0.3 mm/tooth with TiAlN coated carbide inserts. The effects of feed rate on the superficial residual stresses at various cutting speeds were studied. It was found that the residual stresses on the machined surface were very sensitive to the feed rate. The superficial residual stresses at the directions of parallel to and normal to the feed direction both remained compressive and changed obviously in higher compressive direction along with the feed rate. The burnishing effect determined by the cutting force was found to be the primary reason of the residual compressive stresses on the machined surface. The suitable cutting parameters were recommended according to the superficial residual stresses.

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.

Evaluation of the residual stress in stainless steel 304L hydraulically expanded joints

2020 ◽  
pp. 095440892096401
Author(s):  
Ying Hong ◽  
Xuesheng Wang ◽  
Yan Wang ◽  
Zhao Zhang ◽  
Yong Han
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Yield Strength ◽  
Residual Stresses ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
The Finite Element Method ◽  
Power Stations ◽  
Stainless Steel 304 ◽  
Initial Clearance

Stainless steel 304 L tubes are commonly used in the fabrication of heat exchangers for nuclear power stations. The stress corrosion cracking (SCC) of 304 L tubes in hydraulically expanded tube-to-tubesheet joints is the main reason for the failure of heat exchangers. In this study, 304 L hydraulically expanded joint specimens were prepared and the residual stresses of a tube were evaluated with both an experimental method and the finite element method (FEM). The residual stresses in the outer and inner surfaces of the tube were measured by strain gauges. The expanding and unloading processes of the tube-to-tubesheet joints were simulated by the FEM. Furthermore, an SCC test was carried out to verify the results of the experimental measurement and the FEM. There was good agreement between the FEM and the experimental results. The distribution of the residual stress of the tube in the expanded joint was revealed by the FEM. The effects of the expansion pressure, initial tube-to-hole clearance, and yield strength of the tube on the residual stress in the transition zone that lay between the expanded and unexpanded region of the tube were investigated. The results showed that the residual stress of the expanded joint reached the maximum value when the initial clearance was eliminated. The residual stress level decreased with the decrease of the initial tube-to-hole clearance and yield strength. Finally, an effective method that would reduce the residual stress without losing tightness was proposed.

Nanohardness of DC Magnetron Sputtered W – C Coatings as a Function of Composition and Residual Stresses

2015 ◽  
Vol 662 ◽  
pp. 107-110 ◽  
Author(s):  
Michal Novák ◽  
František Lofaj ◽  
Petra Hviščová ◽  
Rudolf Podoba ◽  
Marián Haršáni ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Magnetron Sputtering ◽  
Linear Increase ◽  
Indentation Modulus ◽  
Dc Magnetron Sputtering ◽  
Glass Substrates ◽  
Compressive Stresses ◽  
Deposition Parameters

The effects of residual stresses in thin W-C based coatings were investigated with the aim to find their influence on nanohardness and indentation modulus. Ten samples of W-C based coatings were deposited on microslide glass substrates using DC magnetron sputtering at the identical deposition parameters. Their thickness was in the range from 500 to 600 nm. The residual stresses in the coatings varied from 1.5 GPa up to 4.4 GPa. Increase of residual stress caused linear increase of HITfrom 16 to 19.5 GPa. This increase was only the result of the compressive stresses. EITof the studied coatings was not sensitive to residual stresses and corresponded to 185 GPa ± 15 GPa.

Residual Stress Analysis in Different Thickness TiN Coatings on High-Speed-Steel Substrates

2011 ◽  
Vol 239-242 ◽  
pp. 2331-2335 ◽  
Author(s):  
Fang Mei ◽  
Guang Zhou Sui ◽  
Man Feng Gong
Keyword(s):  
Residual Stresses ◽  
High Speed ◽  
Thermal Stresses ◽  
High Speed Steel ◽  
X Ray Diffraction ◽  
Tin Coatings ◽  
Compressive Stresses ◽  
M2 High Speed Steel ◽  
Steel Substrates ◽  
Different Thickness

TiN coatings were deposited on AISI M2 high-speed-steel (HSS) substrates by multi-arc ion plating technique. The thickness of substrate was 1.0 mm and five thicknesses of TiN coatings were 3.0, 5.0, 7.0, 9.0 and 11.0 μm, respectively. X-ray diffraction (XRD) has been used for measuring residual stresses. The stresses along five different directions (Ψ=0°, 20.7°, 30°, 37.8° and 45°) have been measured by recording the peak positions of TiN (220) reflection for each 2θ at different tilt angles Ψ. Residual compressive stresses present in the TiN coatings. Furthermore, the results revealed that the value of the residual stresses in TiN coatings was high. While the coatings thickness changed from 3 to 11 μm, the residual stresses varied from -3.22 to -2.04 GPa, the intrinsic stresses -1.32 to -0.14 GPa, the thermal stresses -1.86 to -1.75 GPa. The residual stresses in TiN coatings showed a nonlinear change. When the coatings thickness was about 8 μm, the residual stresses in TiN coatings reached to the maximum value.

Changes in Residual Stress in Worked Surface Layer of Type 304 Austenitic Stainless Steel Due to Tensile Deformation

2000 ◽  
Vol 123 (1) ◽  
pp. 130-134
Author(s):  
Makoto Hayashi ◽  
Kunio Enomoto
Keyword(s):  
Solid Solution ◽  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Residual Stresses ◽  
Tensile Deformation ◽  
End Mill ◽  
Heat Treated ◽  
304 Austenitic Stainless Steel ◽  
Type 304

Changes in the residual stress in a worked surface layer of type 304 austenitic stainless steel due to tensile deformation were measured by the X-ray diffraction residual stress measuring method. The compressive residual stresses introduced by end-mill, end-mill side cutter, and grinder were easily changed into tensile stresses when the plate specimens were subjected to tensile stress greater than the yield stress of the solid solution heat-treated material. The residual stresses after the tensile deformation depend on the initial residual stresses and the degree of preliminary working. The behavior of the residual stress changes can be interpreted if the surface-worked material is regarded as a composite made of solid solution heat-treated material and work-hardened material.

Laser Shock Processing of Titanium Alloy Blade and FEM Simulation

2013 ◽  
Vol 456 ◽  
pp. 125-128
Author(s):  
Bing Yan ◽  
Rui Wang
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Residual Stresses ◽  
Fem Simulation ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Tc4 Titanium Alloy ◽  
Compressive Stresses ◽  
Maximum Value ◽  
Shock Processing

The aim of this article is to analyze the residual stresses field in a TC4 titanium alloy blade by laser shock processing (LSP).LSP is a new surface processing technology, it uses the laser shock wave to act on the surface of the target and form residual compressive stresses field. The ABAQUS software is applied to simulate the LSP of TC4 titanium alloy blade, and the distributions of the residual stresses field are analysed.After single LSP,the maximum value of residual stress on the surface is 309 MPa.The residual stresses on the surface increase first and then decrease.The residual stresses at the depth continue decreasing with the increase of the depth.After multiple LSP,the maximum value of residual stress on the surface is increased and plastically affected depth is increased.

Development of Residual Stress Improvement for Nuclear Pressure Vessel Instrumentation Nozzle Weld Joint (P-43+P-8) by Means of Induction Heating

2006 ◽  
Author(s):  
Takuro Terajima ◽  
Takashi Hirano
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Residual Stresses ◽  
Induction Heating ◽  
Weld Joint ◽  
Thermal Stresses ◽  
Pressure Vessels ◽  
Weld Joints

As a counter measurement of intergranular stress corrosion cracking (IGSCC) in boiling water reactors, the induction heating stress improvement (IHSI) has been developed as a method to improve the stress factor, especially residual stresses in affected areas of pipe joint welds. In this method, a pipe is heated from the outside by an induction coil and cooled from the inside with water simultaneously. By thermal stresses to produce a temperature differential between the inner and outer pipe surfaces, the residual stress inside the pipe is improved compression. IHSI had been applied to weld joints of austenitic stainless steel pipes (P-8+P-8). However IHSI had not been applied to weld joints of nickel-chromium-iron alloy (P-43) and austenitic stainless steel (P-8). This weld joint (P-43+P-8) is used for instrumentation nozzles in nuclear power plants’ reactor pressure vessels. Therefore for the purpose of applying IHSI to this one, we studied the following. i) Investigation of IHSI conditions (Essential Variables); ii) Residual stresses after IHSI; iii) Mechanical properties after IHSI. This paper explains that IHSI is sufficiently effective in improvement of the residual stresses for this weld joint (P-43+P-8), and that IHSI does not cause negative effects by results of mechanical properties, and IHSI is verified concerning applying it to this kind of weld joint.

Residual Stress Measurements in a 316L Uniaxial Samples Manufactured by Laser Powder Bed Fusion

2020 ◽  
Author(s):  
C. M. Davies ◽  
P. Sandmann ◽  
T. Ronneberg ◽  
P. A. Hooper ◽  
Saurabh Kabra
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Cross Section ◽  
316L Stainless Steel ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Stress Measurements ◽  
Compressive Stresses ◽  
Central Cross Section

Abstract Uniaxial samples have been manufactured for tension/compression testing from 316L stainless steel by laser powder bed fusion (LPBF). Samples manufactured by LPBF are known to contain high levels of residual stresses. These uniaxial samples were built from a solid cylindrical rod and subsequently machined to reduce the central cross section of the sample to the required gauge diameter and improve the surface finish. Finite element (FE) models have been developed to simulate the LPBF process of the rods, their removal from the build plate and subsequent machining into the tension/compression samples. High tensile residual stresses were predicted at the surface of the samples, balances by similar magnitude compressive stresses along their axis. Post machining however, these stresses were reduced by around 80% or more. Residual stress measurements were performed on the samples post machining using the neutron diffraction techniques. These measurements confirmed that negligible residual stresses remained in the samples post removal from the build plate and machining.

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