Steel Cruciform Sample with Nitrided Arms Achieves Higher Plastic Strain in the Gauge Region

Round 1

Reviewer 1 Report

       The work is interesting  and its results could be usefull  for given  implementation  in e.g. biaxial tensile testing of various materials., development of Forming Limit Diagrams , testing anisotropic sheets etc. 

But there are some remarks: 

   1) Acc. to the title of the paper and abstract we may expact more proper adequate results dealing with the base of the problem : -  too few results of microstructure of test sample  from the point of view of influance of nitriding procedure for increasing the strength of the arms of the specimen  to achieve higher plastic deformation in the centre of the sample.  It  enables the measurement of large deformations  ( plastic strain ) in a gauge region. It will be sensible to add some comments  So  possible adding  required results will improve the work . 

  2) The captions of the figures should reflect the detailes of the figure.  Now they are too concise. 

   3) There are 2 publications in References as self citations. They should be  removed from the list  of References 

   4) English should be checked

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is focusing on the central part deformation of cruciform specimens during biaxial tensile test. After a short literature survey, the Author introduces a new realisation for cruciform specimen applying nitriding treatment on the arms to reach higher strengths for them. Two modified shapes and a non-treated reference specimen were analysed experimentally and using Abacus finite element model. The results of FEM calculations show almost the same stress and strain values for Specimen 1 and 30% difference is observed among them in case of Specimen 2. The Author gives an acceptable interpretation for this difference. The final conclusion of the Author is, that applying the nitriding treatment the deformation of measuring area has been increased over 5% strain and the agreement between experiments and models is acceptable.

The whole paper is absolute correct within the given framework, one question remains about the practical applicability of the new method, namely the deformation of specimen does not reach the limit of diffuse/local necking, which might be a measured point for experimental determination of FLC. Maybe specimen in Fig. 2.b. combined with nitriding would result higher deformation? What is the opinion of the Author?

Some minor remarks:

R112: A bone shaped specimens ???

R147: (nitrided or non-[]9eated, respectively) ???

R167-169: Not appropriate sentence

Author Response

Please see the attachment.

Author Response File: Author Response.pdf