Question on weld zone

By Lawrence (*****)

Date 10-07-2014 14:21

That is a harder question than it appears in my opinion.

I would say "F" The Austinized zone that cools the most rapidly. (assuming steel)

That zone might differ depending on base metal thickness, process, applied heat sinks etc.

Is this a question from one of the test prep pubs ?

By Blaster (***)

Date 10-07-2014 14:27

The simple minded welder that I am I would guess B.

By ssbn727 (*****)

Date 10-21-2014 22:25

I must agree with Blaster in choosing B instead of C.

Respectfully,
Henry

By fbrieden (***)

Date 10-07-2014 17:05

C. Heat affected zone next to the weld metal

By SCOTTN

Date 10-21-2014 15:27

Lawrence,

It's Question 40.

http://www.tensaiteki.com/images/forum_images/CWI_Simulated_Exam.pdf

By welderbrent (*****)

Date 10-21-2014 22:51

To me the wording of the answers in B and C are to be carefully considered.

If it is 'next to' then it is in the other one. So, Heat affected zone next to the base metal is 'in the weld zone'. And, Heat affected zone next to the weld metal is 'in the base metal'. Note: it doesn't say 'in', it says 'next to'.

But remember, there are no trick questions on the CWI exams. :lol:

Personally, my choice would be 'C'. The base metal along the edge of the weld metal in the HAZ is going to exhibit the highest hardness. And a break will occur just to the side of that hard spot pushing it a little further into the base metal where the hard transitions back to proper strength but yields a stress riser with changing properties, grain boundaries, etc.

Now, I'll await the masters' analysis of my poorly worded reasoning.

He Is In Control, Have a Great Day, Brent

By ssbn727 (*****)

Date 10-22-2014 04:04

I could accept your choice as long as the appropriate process was used which is left to question as well as a multitude of other variables to give an accurate answer... The key to the question in my opinion is the fact that both the base metal and the the filler metal have the same strength which means that the strength of the weld metal is going to be a combination of both the base metal and filler metal coalesced, and we know that the weld metal exhibits the lowest amount of hardness because of how soft and ductile it would become... As one moves further away from the center of the weld the hardness increases steadily as it reaches the weld fusion boundary and then continues to rise just past the fusion boundary, and then drops slightly only to rise up again approximately .5 mm outside of the fusion boundary in the HAZ on one side of the weld cross section...

On the other side of the weld cross section, the results are even more pronounced... From the center of the weld the hardness starts to rise higher within the weld zone compared to the previous half of the weld then steadies for .5 mm, drops ever so slightly a@ .5mm from the fusion boundary, and rises up as it reaches the fusion boundary, then steadies to even hardness until approximately 1mm further away only to rise profoundly up 10 Hv @ approximately the middle of the HAZ, and then drops again another 10Hv just approximately 1mm before where the HAZ and base metal meet, then drops almost 50 Hv@ less than .5 mm from the Base metal HAZ boundary, then ever so slightly rising about 1Hv then steady across the rest of the base metal with only marginal change... The chart i'm referring to is in the last page, top left column.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=16&ved=0CEAQFjAFOAo&url=http%3A%2F%2Fwww.scirp.org%2Fjournal%2FPaperDownload.aspx%3FpaperID%3D2246&ei=ERxHVKGRAoS2yQTehoGABQ&usg=AFQjCNGblSOEjkf_bAot2yYsh1r3KyXAig&sig2=2Ax4Oqxr2zZ4WsKnGxiOCA

An interesting paper indeed and yet it doesn't clarify that the highest hardness would be found only in the haz by the fusion zone because of the obvious differences of one side of the weld cross section compared to the other half of the weld cross section.. The only point that it does clarify is that the answer could be either B or C even though only one answer will be acceptable for the test, and it only verifies that some of the questions in the exam need to be more reflective of eliminating any probable ambiguity for an answer to some of the questions written... Besides, nobody's perfect except for you know who. :grin:

Respectfully,
Henry

By welderbrent (*****)

Date 10-22-2014 04:19

Since it is only a practice exam, that question, worded just that way, probably isn't in the current rendition of the CWI Exam. :lol:

But, good discussion. Thanks Henry for your rebuttal.

He Is In Control, Have a Great Day, Brent

By ssbn727 (*****)

Date 10-22-2014 04:28

I enjoyed it too Brent... Thanks.

Respectfully,
Henry

By 803056

Date 11-15-2014 22:12 Edited 11-15-2014 22:17

Too many variables to answer the question without making certain assumptions.

Is the base metal low carbon, medium carbon, high carbon, high strength low alloy, or Q&T steel?

Is the base metal preheated before welding?

What is the heat input; low medium, or high heat input?

I cannot overlook the thickness of the section being welded.

Is the weld a single pass or multiple pass weld?

All the factors would influence the answer.

So, I vote "E."