SA 299 Carbon equivalency 1

[chas49]

Have been offered by mill 6.5" Tk. SA 299 with CE of .57.
Our MOS asked for max of .55. Should we be concerned with weldability ?

 

[stanweld]

Your material is near the maximum for both carbon and manganese. At the 6.5" thickness, I would recommend a preheating temperature nearer to 300 F. I once recommended a similar preheat for similar materials and thicknesses and was rebuffed by the vessel manufacturer who stated that ASME VIII ony required a 200 F minimum preheat and that's what they were going to do. After full circumfirential weld cracking occurred using their 200 F preheat, the manufacturer decided that a somewhat higher preheat (300F) might be warranted and viola no more cracking.

Low hydrogen welding processes are needed. A highly basic, neutral flux is recommende for submerged arc welding.