Disbonding of type 347 weld overlays induced by postweld heat treatments and hydrogen charge

1989 ◽  
Vol 7 (1) ◽  
pp. 35-47 ◽  
Author(s):  
M. De Sanctis ◽  
L. Paganini ◽  
A. Solina ◽  
R. Valentini
Keyword(s):  
Hydrogen Charge ◽  
Heat Treatments ◽  
Postweld Heat ◽  
Weld Overlays

Effect of Local Postweld Heat Treatments on Metal Inert Gas-Welded A7N01S-T5 Joints

2019 ◽  
Vol 28 (6) ◽  
pp. 3622-3629
Author(s):  
Pengcheng Zhao ◽  
Honglei Tang ◽  
Sen Lin ◽  
Lulu Wang ◽  
Jiajing Pan
Keyword(s):  
Heat Treatments ◽  
Inert Gas ◽  
Postweld Heat

Numerical Simulation of CrMo Steels Thick Welds Intermediate Postweld Heat Treatments

2005 ◽  
Author(s):  
Maryline Clerge´ ◽  
Christian Boucher ◽  
Sylvain Pillot ◽  
Philippe Bourges
Keyword(s):  
Heat Treatment ◽  
Complex Shape ◽  
Heat Treatments ◽  
Pressure Vessels ◽  
Post Weld Heat Treatment ◽  
Treatment Conditions ◽  
Stress Relieving ◽  
Creep Resistant Steels ◽  
Postweld Heat ◽  
Hydrogenation Treatment

During manufacturing, complex shape welded pressure vessels are submitted to numerous intermediate heat treatments after each weld (de-hydrogenation treatment - DHT and/or intermediate stress relieving treatment - ISR) before final Post Weld Heat Treatment (PWHT). The present study aims at analysing and optimising the intermediate heat treatment conditions regarding the resulting mechanical properties (tensile strength and impact. strength) of CrMo and CrMoV creep resistant steels. Hydrogen behaviour in weld metal and HAZ, and residual stresses evolution have been assessed by numerical modelling and experimental measurements on welded specimens representative of big pressure vessels: butt welds and set in nozzle welds of 150 mm wall thickness. The optimised conditions are compared to usual construction codes and buyer’s requirements.

Strain-Age Cracking after Postweld Heat Treatments in Inconel 738 Superalloy

2010 ◽  
Vol 29 (1-2) ◽  
pp. 61-68 ◽  
Author(s):  
Seksak Asavavisithchai, ◽  
Weerasak Homkrajai, ◽  
Panyawat Wangyao,
Keyword(s):  
Heat Treatments ◽  
Postweld Heat

Cause and Prevention of Stress-Relief Cracking in Quenched and Tempered Steel Weldments

1972 ◽  
Vol 94 (1) ◽  
pp. 336-341 ◽  
Author(s):  
C. F. Meitzner
Keyword(s):  
High Temperature ◽  
Heat Affected Zone ◽  
Elevated Temperatures ◽  
Stress Relief ◽  
Heat Treatments ◽  
Intergranular Cracking ◽  
Quenched And Tempered Steel ◽  
Postweld Heat ◽  
Tempered Steel

The paper reviews the causes and characteristics of stress-relief cracking, i.e., intergranular cracking in the heat-affected zone that occurs during the exposure of welded assemblies to the elevated temperatures produced by postweld heat treatments or high-temperature service. The findings presented are based largely on work at the Homer Research Laboratories with quenched and tempered steels. Means for preventing cracking during fabrication and service are discussed.

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

Microstructural Development in Nb-Ti Multifilamentary Superconductors During Processing

1985 ◽  
Vol 43 ◽  
pp. 190-191
Author(s):  
A. W. West
Keyword(s):  
Heat Treatment ◽  
Critical Current Density ◽  
Copper Matrix ◽  
Wire Drawing ◽  
Heat Treatments ◽  
Microstructural Development ◽  
Final Size ◽  
Density Values ◽  
The Wire ◽  
Multifilamentary Superconductors

The influence of the filament microstructure on the critical current density values, Jc, of Nb-Ti multifilamentary superconducting composites has been well documented. However the development of these microstructures during composite processing is still under investigation.During manufacture, the multifilamentary composite is given several heat treatments interspersed in the wire-drawing schedule. Typically, these heat treatments are for 5 to 80 hours at temperatures between 523 and 573K. A short heat treatment of approximately 3 hours at 573K is usually given to the wire at final size. Originally this heat treatment was given to soften the copper matrix, but recent work has shown that it can markedly change both the Jc value and microstructure of the composite.

Microstructure Development in a High Current Density NbTi Superconducting Composite

1985 ◽  
Vol 43 ◽  
pp. 186-189
Author(s):  
P. J. Lee ◽  
D. C. Larbalestier
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Cold Drawing ◽  
Heat Treatments ◽  
Grain Structure ◽  
Fine Grain ◽  
Boundary Film ◽  
Quantitative Basis ◽  
Cold Worked ◽  
Very High

Several features of the metallurgy of superconducting composites of Nb-Ti in a Cu matrix are of interest. The cold drawing strains are generally of order 8-10, producing a very fine grain structure of diameter 30-50 nm. Heat treatments of as little as 3 hours at 300 C (∼ 0.27 TM) produce a thin (1-3 nm) Ti-rich grain boundary film, the precipitate later growing out at triple points to 50-100 nm dia. Further plastic deformation of these larger a-Ti precipitates by strains of 3-4 produces an elongated ribbon morphology (of order 3 x 50 nm in transverse section) and it is the thickness and separation of these precipitates which are believed to control the superconducting properties. The present paper describes initial attempts to put our understanding of the metallurgy of these heavily cold-worked composites on a quantitative basis. The composite studied was fabricated in our own laboratory, using six intermediate heat treatments. This process enabled very high critical current density (Jc) values to be obtained. Samples were cut from the composite at many processing stages and a report of the structure of a number of these samples is made here.

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