Cracks, in welds

Zirconium resists attack by nitric acid at concentrations up to 70 wt % and up to 250°C. Above concentrations of 70 wt %, zirconium is susceptible to stress-corrosion cracking in welds and points of high sustained tensile stress (29). Otherwise, zirconium is resistant to nitric acid concentrations of 70—98 wt % up to the boiling point. 

Figure 15.13 Cracking in weld deposit caused by lamination in steel base metal. (Reprinted with permission from Helmut Thielsch, Defects and Failures in Pressure Vessels and Piping, New York, Van Nostrand Reinhold, 1965.)...

F. Feed/effluent exchanger nozzle-to-shell weld, cracks in welds and in exchanger tubes. 

Cross section of channel of exchanger./Note cracking in weld metal at right (light colored area) of specimen.3... 

Similar comments are applicable to weld metal hydrogen cracks, with the further observations that cracking in weld metals is frequently transverse to the weld and that in weld metals of the acicular ferrite type, cracking is most common in the primary ferrite (if it is present) at the prior austenite grain boundaries, as in Fig. 1.3(a). In relatively hard, alloyed weld metals (e.g. in the Cr-Mo steels) any transverse weld metal cracking is usually perpendicular to the weld surface, but in C-Mn weld metals the chevron type of cracking (Fig. 1.3(c)) at 45° to the surface is common. 

Selected bibliography of TWI papers on hydrogen cracking in welding... 

Coe F R The avoidance of hydrogen cracking in welding . Proc 1st Int Symp, Jap Welding Soc, Tokyo, Nov 1971, 2, Paper 11B5. 

Stainless steel type 321 with addition of titanium has been used to enhance the mechanical performance of the structural material at high temperature (520-550 C). The intensive French programme of non-destructive tests since 1989 has shown that 321 stainless steel has not performed satisfactorily over time, with cracks in welded joints occurring under load and high temperature. The sections of Phenix secondary pipework made in this steel have been replaced by 316SPH steel. 

The alloys of 11 compositions were studied, as shown in the test matrix (Table IV). Characteristics of the tensile strength and ductility of the parent metal and welded joints at 293, 77, and 4 K and the index of susceptibility of the alloys to cracking in welding are given in Tables V and VI. Equations of regression were derived from the test results. To determine the correlation between the mechanical properties of the Al-6Cu-Mn-type alloys and the chemical composition of the alloys, all data obtained in the experiments were considered in the calculation. 

Dye penetration/magnetic particles tests— to detect cracks in welded joints... 

Any cracks in welds attaching disc wheel disc to rim. 

Any crack in welds attaching tubeless demountable rim to adaoter. 

Any crack in welds attaching tubeless demountable rim to adapter. (393.205(a))... 

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