Effects of PWHT on the Residual Stress and Microstructure of Bisalloy 80 Steel Welds

Round 1

Reviewer 1 Report

the authors analysis the relationship among residual stress, hardness and microstructure of Bisalloy 80 weld and the PWHT. this analysis and conclusion can provide improtant reference value for the welding of this kind of materials.

however, some improvement should be carried out before publicaiton.

(1) what is the rolling direction of the plate, and the authors shoud carry out two direction welding，parallel and  perpendicular welding respecatively and compare the difference of the microstructure and hardness and residual stress.

(2) how many weld layers and if the mulit passes can affect the hardness and residual stress?

(3) residual stress was manly afected by structure restrain, in this case, there is little structure restrain, and how the microsture and hardness aftect the residual stress?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

English correction of the whole submission has to be carried out. Some sentences are non sense as they have no verbs (eg. "The superior weldability of these alloys, although effective in mitigating the formation of weld cracks, but still undergo microstructural changes ..." in page 1, line 34) and some strange expressions are used such as "softzened" in p.1 or "was occurred" in p. 2.

The internal stresses have been measured using neutron diffraction but:

- one can regret that this is not indicated in the title nor in the abstract

- no error bars are mentioned such as in the abstract (631 MPa) 

- the stress field remains invariant to some extent along the welding direction: please mention if the stresses have been measured in the mid length of the plates. The authors could also have taken advantage of this by taking a gauge volume elongated in the welding direction to get a faster and better neutron statistics. Please comment on this.

- the authors have had to measure the strains in 3 orthogonal directions to calculate the diagonal components of the stress tensor (Poisson's effect) so the normal stress should also be shown in fig. 3  even it it is rather low in magnitude as mentioned in the text.

- the welding of the plates have to further detailed: clamping ? number of passes ?

- is the Q & T steel a fine grain steel ? this is not clear ... 

- avoid expressions like " well-known" in p. 4 and "can be".

- the stress-free samples seem rather big to me: please comment why such a size can relax all internal stresses.

- if all conditions during welding are symmetric (except maybe the different passes), then the stresses should also exhibit such a symmetry through the plane x = 0. This seems to be the case. One can regret that the error bars hardly appear and that the authors do not comment the classic W stress profile found in the weld (see literature).

- I remain very sceptical when reading the interpretation of fig. 5 in page 8. For example, the grain size mentioned to be 20 - 30 microns is not visible in the figure: one has to use polarized light or EBSD to determine the grain size. 

As a conclusion, the authors have proven by measurements that the PWHT is efficient in reducing the internal stresses (thank god !) but they did not really address the question of how much extra tempering the welding per se does bring to the alloy in the HAZ. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

the authors have provided good revision and I agree to publish.

Reviewer 2 Report

I can accept the answers to the questions/comments I raised. I simply want to mention that stress is a tensor with 6 components as it is symmetric. The Von Mises stress is its second invariant and is always positive. It is useful only to detect if plasticity occurs or not ... Thus one has to be precise when we refer to stresses.