1045 Normalized Round Bar Charpy Problem 2

[bflann]

Hello everyone and thank you for reviewing my post/question and offering your expert opinions.

Here is the trouble: I have a project I am working on that calls out for the following: CAN/CSA G40.21 Grade 300W OR AISI 1045 in the Normalized Condition. Needs to conform to min yield of 350MPa and tensile of 480MPa. 15% min elongation and cat. 3 Charpy Impact Testing with Min. absorbed energy of 27 Joules.
I have 3", 4.75", 5", 6", 7" and 10" round bar in a normalized 1045 that has everything in line EXCEPT the charpy values which are reading between 11 and 15 Joules average. I asked my customer to review his specification of 27 Joules but I am so far off something has to be missing from his spec.?

Any advice on how to increase the Joules? I do not see any way I can get to a 27 min. Joules with this steel no matter what process I put it through. There has to be a problem with the spec.?

Thank you.

 

[metengr]

bflann;
What is your minimum test temperature for CVN impact? Why is the 1045 steel being permitted when CAN/CSA G40.21 Grade 300W is specified? You can look at tempering after normalization to see if you can improve the impact numbers, but I doubt it as well.

 

[bflann]

Sorry for leaving out that critical piece of information. Testing is done at -20 degrees.
They gave us an option to use "either/or" in the case of the grade 300W or 1045. The 1045 was more readily available and after talking with our lab personnel, we believed the 27 Joules would not have been a problem.
That is clearly not the case.

 

[CoryPad]

What are the sulfur and phosphorus concentrations?

What are your actual yield/tensile/elongation values?

 

[metengr]

bflann;
Because of the 0.45 mass percent carbon content, you are going to need to have an alternate heat treatment other than normalization to achieve this minimum impact value at
-20 deg F.

Also consider 1045 has very limited hardenability, and as such larger diameter grades will be even more diffucult to achieve this minimum impact value using only normalization heat treatment.

 

[bflann]

Results for CORYPAD attached.

METENGR - testing was -20 C, I assume that will make a difference?

 

[stanweld]

With the diameter's and chemistries provided, your results are predictable. You may be able to double nomalize the materials to salvage them for use. Q & T is more likely to achieve the desired results.

 

[EdStainless]

You might want to try N&T first and see if it helps. I doubt that it will be enough but you can at least see if temper is of benefit.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[bflann]

Double normalizing would be ideal, as it is about 1/4 the cost of a Q&T. I am working with the Q&T and Normalizing facilities now to find out what they can guarantee as far as results are concerned. I am under the gun, obviously under knowledged, and in trouble with costs. Happy New Year to me.

 

[salmon2]

From the chemistry bflann posted, the chemistry doesn't seem like a standard 1045, it is more like a hsla steel for plate to me cause it has Cr, Ni, Mo, even V. 6.0 dia heat got a questionable TS and elongation somehow.

27J or 20 ft-lb for -20C is difficult for a normalized structure, but fairly easy for a Q&T steel with appropriate chemistry. Current chemistry seems lean for Q&T, especially for the large diameters.

One suggestion to your current double normalizing plan is that you may want to check the grain size right now. if it is already fine, I suspect how much benefit you can get?

 

[bflann]

Great feedback form everyone - thank you.

Moving forward, to avoid these issues, what grade of round bar steel would best perform to hit the 27Joules minimum with just a normalize - is any?

Again the customer clearly specified either:
CAN/CSA G40.21 Grade 300W
or
AISI 1045 in the Normalized Condition - clearly this is not the right option to keep costs down.

Being from the states I am unfamiliar with the 300W spec. but the customer called today and asked the next batch try to come from 44W as well. I don't want to keep tripping over this and spending too much time and money if we can not get it right.

 

[salmon2]

bflann,

In my mind, the requirement is high for a normalized steel, unless you can get extremely fine grain structure. It is not the chemistry, it is the normalized structure which has high DBTT, not suitable for low temperature usage.