704 Effects of Subsequent Pass Heat Input on Residual Stress Profile Generated by Previous Pass in Low Alloy Steel Plate Weld Accompanying Phase Transformation

2012 ◽  
Vol 2012.20 (0) ◽  
pp. 181-182
Author(s):  
Nobuyoshi YANAGIDA ◽  
Koichi SAITO
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Alloy Steel ◽  
Heat Input ◽  
Steel Plate ◽  
Stress Profile ◽  
Low Alloy Steel ◽  
Residual Stress Profile

Residual Stress Analysis of Bead Welded Low Alloy Steel Plate Specimens Subjected to Post Weld Heat Treatment

2011 ◽  
Author(s):  
Nobuyoshi Yanagida ◽  
Koichi Saito
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Phase Transformation ◽  
Stress Analysis ◽  
Alloy Steel ◽  
Steel Plate ◽  
Post Weld Heat Treatment ◽  
Welding Residual Stress ◽  
Low Alloy Steel ◽  
Residual Stress Analysis

We developed a residual stress analysis method for bead welded low alloy steel JIS SQV2A (equivalent to ASTM A533B cl. 1) plates subjected to post weld heat treatment (PWHT). Two specimens were fabricated; each was a bead welded low alloy steel plate. One was in the as-welded condition (as-welded specimen) and the other was subjected to PWHT at 625°C (PWHT specimen). Strain gauges were used to measure the distributions of the residual stress in these specimens. The measurement data showed that the longitudinal stress at the center of a bead was 0 MPa and that in the heat-affected zone was 100 MPa. The transverse stress at the center of a bead was 200 MPa in the as-welded specimen. The absolute residual stress was decreased to less than 50 MPa for the PWHT specimen. We conducted finite element analyses to predict the distributions of welding residual stress in these specimens. The amount of phase transformation strain in low alloy steel was taken into account in the welding residual stress analysis, and creep strain was taken into account in the stress mitigation analysis. The results from the analyses agree well with the experimental results. These findings prove that welding residual stress can be simulated during a thermal elastic plastic (TEP) analysis by conducting a phase transformation and taking the generation of creep strain in the PWHT samples into consideration can be used to simulate that stress mitigation.

The Mechanics Basis of Residual Stress Profiles in Proposed API 579 Appendix E

2006 ◽  
Author(s):  
P. Dong ◽  
Z. Cao
Keyword(s):  
Residual Stress ◽  
Heat Input ◽  
Stress Measurement ◽  
Measurement Data ◽  
Stress Profile ◽  
Continuous Change ◽  
Parametric Function ◽  
Residual Stress Profile ◽  
Stress Profiles ◽  
Pipe Geometry

In this paper, the mechanics basis underlying the parametric through-thickness residual stress profiles proposed for the revised API 579 Appendix E are presented. The proposed residual stress profiles are governed to a large extent by a unified parametric function form valid for a broad spectrum of pipe and vessel welds. The functional relationship is established based on the comprehensive knowledge base developed within a recent major international joint industry project (JIP) under the auspice of Pressure Vessel Research Council (PVRC) and a large amount of residuals stress measurement data from recent literature. One of the most important features associated with the proposed revision is that residual stress profile is uniquely determined by two important sets of governing parameters: (1) parameters relevant to pipe geometry, i.e., r/t and t; (2) a parameter related to welding linear heat input Q (J/mm), referred to as the characteristic heat input Qˆ which has a dimension of J/mm3. As a result, the corresponding through-wall residual stress distribution exhibits a continuous change as a function of r/t, t, and Qˆ, instead of falling into a few discrete and unrelated profiles, as seen in the current Codes and Standards.

Residual Stress Profile of Ultra High Strength Low Alloy Steel Induced by High Speed Milling Process

2013 ◽  
Vol 658 ◽  
pp. 188-193
Author(s):  
Kun Qiu ◽  
Zhen Hai Long
Keyword(s):  
Residual Stress ◽  
Compressive Stress ◽  
High Speed ◽  
High Strength ◽  
Cutting Parameters ◽  
Milling Process ◽  
Depth Of Cut ◽  
Stress Profile ◽  
Low Alloy Steel ◽  
Residual Stress Profile

In order to improve the surface quality of ultra high strength low alloy steel work-pieces produced by high-speed face milling process, 23-1 factorial design experiment was con-ducted and the residual stress profiles within the surface and subsurface layer of work-pieces were measured. Corresponding empirical models for the residual stress profile were presented and the effects of cutting parameters (cutting velocity, feed per tooth, depth of cut) on characteristics of the residual stress profile were studied. Results show that: with the range of cutting parameters tested, the compressive residual stress profile would be induced below the work-pieces’ surfaces machined by high speed face milling process. Feed per tooth has the critical influence on the characteristics of the compressive stress profile, and the mechanism of residual stress generation will be different when feed per tooth changes in high speed machining process. To obtain higher compressive stress and deeper compressive stress profile depth, larger feed rate and depth of cut are required.

Study on Residual-Stress Redistributions During the Process of Manufacture of a Vessel Penetration Set-On Joint

2009 ◽  
Author(s):  
Nobuyoshi Yanagida ◽  
Kazuo Ogawa ◽  
Koichi Saito ◽  
Ed Kingston
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Alloy Steel ◽  
Steel Plate ◽  
Three Dimensional ◽  
Hole Drilling ◽  
Low Alloy Steel ◽  
Butt Weld ◽  
Control Rod ◽  
Inner Surface

The stress-redistribution phenomenon in a vessel penetration set-on joint due to post-weld heat treatment (PWHT) was studied using finite element (FE) analyses and mocked-up experiments. The mocked-up consisted of a nickel-based alloy (NCF600) tube welded onto an alloy-82 cladded, low-alloy steel plate (SQV2A) using an alloy-182 butt weld. The angle of the tube to the plate surface was 45 degrees, simulating a side hill, a control rod drive (CRD), and a stub-tube nozzle attachment used in boiling-water reactor (BWR) plants. PWHT at a temperature of 625 °C was conducted after welding and then the inner surface of the tube was machined. Three-dimensional FE modeling was performed to simulate the cladding, the butt weld, the PWHT, and the inner-surface machining of the tube. Thermal elasto-plastic and thermal elasto-plastic creep analyses were conducted to simulate the process of residual-stress build up and its redistribution by PWHT. To validate the FE analysis, the residual stresses in the mocked-up specimen were experimentally measured using the deep-hole-drilling (DHD) and sectioning methods. The analytical and experimental results revealed that residual-stress redistributions in the mocked-up specimen were different in circumferential positions. High-residual stresses in the low-alloy steel plate were particularly mitigated during the PWHT. The stress relief in the low-alloy steel plate primarily controlled the global stress balance between the cladding, the weld metal, and the stub tube.

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