Page 100 - SSAB Welding Handbook Edition 2

©2009-2019 by SSAB Group of companies (SSAB). All rights reserved. Only digital PDF file. No distribution. No printing allowed!
No part of this handbook may be reproduced in any form or by any means without permission in writing from SSAB.
16.0 Post-weld heat treatment Welding handbook

The exact changes in mechanical properties in the 16.1 Aspects regarding welding
joint due to a PWHT depend on how the process processes
©SSAB
is carried out. However, the yield strength, tensile
strength, impact toughness and hardness in the joints Structures that are going to be post-weld heat
and other parts of the parent metals will often be treated can be welded using all types of conventional
decreased to some extent. welding methods including MAG welding, MMA
welding, SAW and TIG welding.
The issues regarding the effect of a PWHT on the
toughness properties in the joint may seem
contradictory. However, toughness depends on both 16.2 Suitable consumables for
residual stresses and external load. External forces welding of structures that are
and residual stresses promote brittleness; welded subjected to a PWHT
structures are subjected to both. Small Charpy-V
test specimens used for impact toughness tests, Several types of consumables are appropriate for
on the other hand, have lowered residual stresses this type of application. The basis for selecting
when they are removed from the joint. As a result, a proper consumables is according to our normal
small test specimen subjected to a PWHT may show recommendations. Make sure that the consumable is
lowered toughness values than if it were a part of a suitable for use in structures subjected to a PWHT.
larger structure subjected to a PWHT. This information can be attained from the consumable
manufacturer.
The properties in the unaffected parent metal are not
significantly changed because of a PWHT. A general concern for MAG welding with flux cored
wires is the higher fraction of basic wires compared
In order to attain the desired characteristics in the to rutile wires that are applicable to structures
welded structure, SSAB recommends that the relevant subjected to PWHT.
properties are evaluated for the specific situation
prior to welding.
16.3 Other types of requirements
Normally, a PWHT is performed for the complete Contact SSAB for further advice if there are other
component. A PWHT can, however, be executed for requirements involved in the execution of the
separate parts of the structure. Contact SSAB for PWHT procedure that are outside of those
further assistance in the latter case.
recommendations specified in this chapter.

100 This handbook contains general suggestions and information without any expressed or implied warranty of any kind. SSAB hereby expressly disclaims
all liability of any kind, including any damages, in connection with the use of the information and for their suitability for individual applications.
It is the responsibility of the user of this brochure to adapt the recommendations contained therein to the requirements of individual applications.