Is there a ASTM method for estimating grain size in welds? 3

[EngineerDave]

I know this is a dumb question, but I was asked to provide a grain size of the weld material (not the base metal or heat affected zone). Since the weld material is very irregular can one truly provide a grain size of the weld?

Thanks in advance for any help. I know I didn't provide alot of details on the weld itself, it's mainly because I don't have much info on it. But it is weld filler material and the microstructure is very irregular. Not sure I can even provide a true grain estimate, but maybe some size information.

 

[metengr]

EngineerDave;
From the publications I have seen, the ASTM method E112 (intercept or other) for determination of grain size can be applied to wrought or cast product forms. Welds would be considered a cast product form.

 

[unclesyd]

I never seen a grain size on as welded product due it being mostly dendritic.

 

[metengr]

unclesyd;
Yes, I have never seen welds have a grain size identified for components we purchase. On the other hand, I don't see why you couldn't attempt to determine an average grain size using the intercept method where you would have a columnar grain structure instead of all dendrites.

As a side note, I did see a technical paper where the weld grain size was determined using the intercept method, which caught my attention. It must have been an academic exercise.

 

[EngineerDave]

Thanks guys. The dendritic structure and absence of clear boundaries are exactly my problem. I just finished explaining that to my customer.

I'll let you know if we give it a try. I would use my image analysis software and an intercept method.

 

[TVP]

Dave,

FYI, there are a number of ASTM methods that discuss grain size including the following:

ASTM E 1382 Standard Test Methods for Determining Average Grain Size Using Semiautomatic and Automatic Image Analysis

ASTM E 930 Standard Test Methods for Estimating the Largest Grain Observed in Metallographic Section (ALA Grain Size)

ASTM E 1269 Standard Practice for Assessing the Degree of Banding or Orientation of Microstructures

You may want to consider more than just an intercept technique, for the reasons already stated.

 

[sayee1]

My only contribution to this post were the stars!!!!

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Sayee Prasad R
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