English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

There has been uncertainty whether postweld heat treatment (PWHT) should be required for external attachment welding applications where stress corrosion cracking (SCC) is a possibility. An industrial criterion established by NACE SP0472, paragraph 3.6.1, indicates PWHT is not required if tensile residual stresses do not extend through the entire wall thickness. To investigate this problem, a finite-element analysis (FEA) software, SysweldTM, was utilized to predict the extent and level of residual stresses of such welds through the thickness of the pressure vessel shell to study the influence of clamping and preheating. Experimental validations following AWS A9.5 standard were performed. The study used ASTM-516 grade 70 steel plates of 6.3, 12.7, and 19 mm thicknesses. The effects of rigid clamping and preheating from 95 to 135Con the residual stress distributions following the thickness direction were studied.The clamping condition results showed residual stresses were increased consistently in the weld metal and heat-affected zone (HAZ) at significant levels observed at 6.3 mm thickness and minimum levels at 19 mm. Such effect was attributed to lower distortion displacement at higher pressure vessel thicknesses compared to the higher distortions at lower thicknesses. Due to thermal strain reduction and insignificant changes of metallurgical phase amounts, the residual stresses in the thickness direction were slightly decreased due to preheating. When welded with preheating or clamping, maximum tensile residual stresses exceeding 80% of yield strength existed in the bottom surface of the 6.3-mm-thick plates but only 19 to 30% yield strength in the 19-mm-thick plates. The conclusions indicate that 6.3-mm-thickness applications demand PWHT whereas 19 mm or greater thicknesses are potentially safe depending on the loading conditions.

Quantification of Residual Stresses in External Attachment Welding Applications - Part II: Effect of Preheating and Clamping Conditions