5% chrome 0.5% molybdenum

[HiYa]

We have been welding 5% chrome 0.5% molybdenum (P num. 5C) with ER502 and E502. I understand that these are the earlier classifications of the welding materials. I have noticed that the filler wire (ER502, E502) is easier to cut and bend than the 1 1/4 percent chrome welding materials (ER80SB2). It is softer than the welding materials containing lower chrome contents. I would have thought that a material containing more chrome would be harder to cut and not as ductile as one containing less chrome. Anyone have any experience with these materials?

 

[Metalguy]

This question is a repeat of one a few days ago. It was answered then.

 

[HiYa]

I asked the question in this forum because I didnt get anything from the other responses, maybe I just didnt understand the responses. I would not have re-posted the question just for lack of better things to do.

 

[Metalguy]

OK, one more time. Here's what I wrote back then.

"No experience, but annealed 5% Cr steel would be softer than slightly cold-worked plain carbon steel. The potentially huge effect of 5% Cr isn't seen when the steel is annealed."

What this means is that the addition of 5% Cr won't change the hardness or ductility when the steel is annealed-or at least not change it much at all. A plain carbon or 1 1/4% Cr steel, if slightly cold-worked as might be done in making welding wire and not fully annealing it after drawing the wire through the wire dies would be harder and have less ductility.

However, Cr has a very strong influence on what happens when a steel is heat treated-meaning the hardening and quenching process where the steel is heated to ~1500 deg. F or higher. It also has that effect as it cools from the welding temp.