Dataset on full width at half maximum of residual stress measurement of electron beam welded high strength structural steels (S960QL and S960M) by X-ray diffraction method

In this paper, we presented the dataset values of full width at half maximum (FWHM) with errors at each point corresponding to the value of longitudinal and transverse residual stress along the three lines for 14 points measured in the EBW welded joints (S960QL and S960M) of the related article [1]. This dataset is used to plot figures and describes their correspondence points with the interrelation of the residual stress graphs (Fig. 4) of the article [1]. The shape of the diffracted peak can be characterised in a simple way by the FWHM, which is the width in degree at half the peak height after background extraction. The measured width consist of instrumental and metallurgical broadening. The variation or increase in FWHM is resulted from the crystalline lattice defect e.g. solute foreign atoms, dislocations and grain boundary. Conversely, if we can determine the physical broadening, we get more information about the structure of the investigated material. In addition, the optical microscopic image of the base materials and weld microstructure are the other parts of the data. Diffraction data were collected using centreless X-ray diffraction (XRD) during in situ residual stress measurement of high strength structural steels S960QL and S960M. A more detailed interpretation of the data presented in this article is provided in article [1]. The presented data are produced as part of the main work entitled “Comparative evaluation of residual stresses in vacuum electron beam welded high strength steel S960QL and S960M butt joints [1]”.

and S960M. A more detailed interpretation of the data presented in this article is provided in article [1] . The presented data are produced as part of the main work entitled "Comparative evaluation of residual stresses in vacuum electron beam welded high strength steel S960QL and S960M butt joints [1] ".  Table   Subject Mechanical Engineering Specific subject area Electron beam welding, Residual stress, High strength structural steel Type of data Table  Image Graph How data were acquired X-ray diffraction, Stresstech XStress Robot centreless X Ray diffractometer. Optical microscope, microstructure images were taken by using an Axio Observer D1m (Zeiss) inverted microscope. Description of data collection -XRD data was collected using 1 mm collimator size in diameter. 7

Value of the Data
• The residual stresses of different orders are present together in the material, often regardless of the cause. While the first-order stress causes the Bragg angle shift, the third-order stresses increase the FWHM value. Therefore, when examining the residual stress, it is advisable to monitor the change of both parameters as well, because we can obtain additional information about the conditions of hardening. • The data will benefit researchers, structural and welding engineers, modelling engineers exploring deformation mechanisms, residual stress determination with different welding processes and their interaction in HSS e.g., S960QL and S960M. • These data can be used further to compare the FWHM results with same grade high strength steel welded joint with different welding processes or higher strength steel grades welded joint with gas metal arc welding (GMAW) process or other welding processes to analyse the value of FWHM which is increased by everything that results from the defect of the crystalline lattice and causes a third order residual stress.
• Data can be used to compare the residual stress measurements made by other measurement techniques e.g., neutron diffraction or deep hole drilling methods. • The data can be used to validate and calibrate future numerical modelling of residual stress distribution and FWHM.

Data Description
The data provided in this paper relate to the paper published in the Vacuum Journal [1] . The raw and analysed data on FWHM with scatter values at the corresponding points of the residual stresses measured at 14 different points each in three different lines of the welded joint shown in Fig. 3(b) [1] are presented in this article. The schematic diagram, Fig. 3(b) [1] provides the details scheme or pattern of the measured residual stress and their corresponding FWHM used for the X-ray diffraction method. The dataset used for plotting graphs in

Experimental Design, Materials and Methods
In this experiment, two base materials (BM) namely WELDOX 960 E (S960QL in EN 10025-6) and ALFORM 960M (S960M in EN 10149-2) with plate thickness 15 mm were used. Their chemical compositions and mechanical properties are presented in the article [1] . These two steels are differing in their carbon and micro-alloying element content and thus so in CEV and CET [2][3][4] . The plates with dimensions 300 × 150 × 15 mm (according to EN 15614-11:2002) in two pieces for butt welded joint were used under high vacuum of 2 × 10 −4 mbar for electron beam welding using an EBOCAM EK74C-EG150-30BJ EBW machine. The electron beam welding process is  an innovative and versatile technology [5] . The underlay plate with dimension of 300 × 50 mm is used for EBW process with not through penetration mode to obtain sound result, assembled with original butt welded joint. The edges of the samples and assembly unit of backing plate with butt joint plates were properly cleaned and milled to the maximum allowable gap of 0.15 mm. The electron beam welded joint without filler material with full penetration was obtained after several trials and the beam pattern was straight oscillation with the amplitude of 1 mm. The optimal welding parameters used in this investigation are same for the BM which are shown in Table 1 . The metallographic samples for optical micrography observations were sectioned through the weld in transverse direction. The sectioned samples were polished with SiC waterproof papers in series of 120, 40 0, 80 0 & 20 0 0 ANSI grit and finally with a disc using diamond paste of 1 μm. The specimens were then etched with Nital (2% HNO 3 ) for 10 s to observe microstructure in base materials and weld materials. The resulting image of optical microstructures ( M = 500x) of S960QL and S960M base material are shown in Fig. 2 a and b, respectively. The microstructure of S960QL base material is consists of tempered martensite (TM) and bainite and of S960M consists of upper bainite (B U ) and tempered martensite (TM) [6] , shown in Fig. 2 a & Fig. 2 b, respectively.   Optical micrographs of weld centre of the S960QL and S960M EBW joints are shown in Fig. 3 a  and b, respectively. The S960QL fusion zone reveals that it consists of fine dendritic martensite grains ( Fig. 3 a) which are perpendicular to the weld centre line (weld pool) while S960M shows mainly martensitic microstructure is clearly observed in Fig. 3 (b).
Residual stress measurements are particularly important for the introduction of advanced joining processes, such as electron beam welding, friction stir welding etc., into commercial usage [7] . In turn, it helps to understand FWHM profile variation of the as-received measurement  along the measured points of the welded joint to correlate well with the residual stress corresponding result.
Then after, FWHM distribution for the corresponding points of residual stress (RS) were measured at 14 measurement points with distance of 1.5 mm between each point in three lines i.e., top, middle and bottom by the X-ray diffraction method on full size EB welded specimen in the as-welded state by Stresstech XStress Robot centreless X Ray diffractometer and the detailed schematic of the pattern of RS measurement and experimental procedure are provided in article [1] .
This method of measurements is advantageous in carried out accordance to the well-known sin 2 technique [8] (where is the angle between the diffracting planes and the specimen surface) where small depth of penetration signify that the sampled region assumed to be in plane stress [9] . XRD method is also called as non-destructive stress measurement technique. The characteristic's features of high strength structural steels like S960QL and S960M are make it exceptional for the application in the field of engineering structure and highly loaded constructional components like heavy duty trucks, cranes, bridges, mobile cranes etc. [10 , 11] .

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships which have or could be perceived to have influenced the work reported in this article.