https://mechcalc.net/blog/en/tags/pwht/ Recent content in PWHT on MechCalc how-to Guide https://mechcalc.net/blog/og-default.png https://mechcalc.net/blog/og-default.png Hugo en Wed, 24 Jun 2026 13:00:00 +0800 https://mechcalc.net/blog/en/posts/bs7910-a533b-hlht-fad-walkthrough/ Wed, 24 Jun 2026 13:00:00 +0800 https://mechcalc.net/blog/en/posts/bs7910-a533b-hlht-fad-walkthrough/ The finale of the four problems on the A533B-1 welded plate: same temperature and regime as Problem 3 (HLAW) — −30 ℃, high load ratio — but with post-weld heat treatment (PWHT). This article works through HLHT to show the double dividend of PWHT — it both relaxes the residual field (K_I^S 46→5) and restores toughness by an order of magnitude (K_mat 62→321) — and how this drives K_r down from 3.94 to 0.60; plus a thought-provoking twist: even with smaller residuals and higher toughness, HLHT fails at a slightly lower load than HLAW. https://mechcalc.net/blog/en/posts/bs7910-a533b-llht-fad-walkthrough/ Wed, 24 Jun 2026 11:00:00 +0800 https://mechcalc.net/blog/en/posts/bs7910-a533b-llht-fad-walkthrough/ Second of four problems on the A533B-1 welded plate: same temperature as Problem 1 LLAW (−120 ℃), same region, same measured residual-stress profile — the only variable is that post-weld heat treatment (PWHT) was applied. Here we run LLHT in mechCalc's BS 7910 Clause 7 fracture-assessment calculator and watch a counter-intuitive result: its primary SIF is actually higher than LLAW, yet the assessment point lands lower, because the residual K_I^S drops from 46 to 5.