But They Are There!!! ( Cr, Cu, NI, V, Ti in Carbon steel) 7

[Tmoose]

A report on line has a slide that has these comments -
[ul]
[li]"Residual Elements found in Carbon Steel (i.e. Cr, Cu, NI, V, Ti)[/li]
[li]MTR’s Normally do not test for these Elements and should not be in the Carbon Steel ![/li]
[li]But They Are There!!! "[/li]
[/ul]

I realize many ASTM specs for carbon ( non alloyed )contain limited elements in the recipe, but is is accurate to say any other elements are forbidden ?

 

[IRstuff]

I think that would be wishful thinking. Anything that's not part of the alloy recipe is simply a) not measured, and b) not necessarily a trace amount.

We had a boron contamination that was traced to process piping. It wasn't listed and wasn't tested, although, the data might possibly have existed. Most of the literature doesn't even mention boron as a possible residual, only a couple of obscure papers even talked about it.

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[kingnero]

Isn't Boron beneficial while pouring the liquid steel, while even trace % is detrimental to welding?

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[weldstan]

Other residual elements are not forbidden. In fact they will always be there in different amounts depending on the mills making the steel and the steel making methods used therin (ore, scrap metal, etc.). Some elements are incorporated to define the mill making the steel. In the steel mill where I originally worked, we had Co content in our ore that identified steel as being ours. This was highly useful when reviewing claims from customers. If Co range not found, we informed the customer that it was not our steel. At one point I could identify at least 5 different mills based on residual elements chemistry.

 

[Tmoose]

Hi IRStuff,

RE: Boron - Were you referring to Note E in the image I provided ? That was stolen from ASTM A29.
I Googled around a little for killed steel, and don't think I found much about elements other than Silicon or Aluminium or both.

thanks,

Dan T

 

[IRstuff]

No, that was probably coincidence. Nevertheless, boron is seemingly ubiquitous, but rarely assayed, so no one really knows for sure. All I know is that we spent months tracking down the contamination, and even after several tests that pointed specifically to the piping, there were still a ton of doubters, particularly those that said that the steel assays didn't show boron. But, that's because they don't test for it, or don't publish the trace value because it's otherwise compliant to its spec.

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[bobjustbob]

I am unfamiliar with the ASTM standard that you have posted, however, often residual element requirements may not be listed in the table but may be restricted or allowed in another section. Also, you quote a "report on line." Without some context of what the purpose of the report it is impossible to make too many remarks on the claims in the report.

The elements that you have listed are commonly found in steel. In the foundry industry, where we generally remelt steel from other operations, I would be surprised to get scrap in without at least .08% Ni and Cr or without .15% Cu. V may be in there to a lesser amount. Not common but not unheard of. Ti can be used as a deoxidizer or to tie up nitrogen. I have never made bar stock but we would use a bit of FeTi in different casting steel grades.

It is not impossible to make steel with no detectable amounts of these elements, it is just more costly. If the trace amounts do not negatively affect the properties then it is not worth the cost.

 

[arunmrao]

Steel founders, who regularly process from assorted scrap encounter surprises from residual elements. There could be a rash of hot tears, cracks during heat treatment or loss in ductility. I am reproducing a sample for ASTM A216Gr WCB. For the past 20 years valve manufacturers are looking closely at residual elements in MTRs. Any suspicious element is red flagged.

I am seeing Cobalt about 0.1-0.15% in steel scrap these days.These are automobile scrap.



ASTM A216 Gr WCB
Carbon: 0.30% Max
Manganese: 1.00% Max
Silicon: 0.60% Max
Phosphorous: 0.035% Max
Sulphur: 0.035% Max
Nickel: 0.50% Max
Chromium: 0.50% Max
Molybdenum: 0.20% Max
Copper: 0.30% Max
Vanadium: 0.30% Max
Residual Elements: 1.00% Max

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[Tmoose]

Here is a link to The report that seemed to me to say, " Carbon steel should be free of any Cr, Cu, NI, V, Ti "

http://www.apisingapore2012.org/Doc...lication Procedures for API 578 PMI Final.pdf

It's focus is toward API guidance for prevention of carbon steel piping corrosion in refinery service.

 

[Maui]

The material specification that accompanies the purchase order the customer sends to the steel manufacturer should specify the allowable chemical limits for each of the alloying elements and any trace elements that are of concern. It is the customer's responsibility to clearly define the chemical requirements for the grade of steel they want to buy. It is the supplier's responsibility to ensure those requirements are met.

Maui

 

[metengr]

Unfortunately, with use of recycled steel comes the bad news that tramp elements once barely detected in quantity and ignored can increase in concentration and result in deleterious effects on performance. Hot metal has to be used in conjunction with carefully sorted steel scrap to control the level of residuals to ensure proper chemistry.

Second point, ASTM specifications are driven by suppliers rather than users. This creates an interesting situation when it comes to consensus on what elements should be reported and at what concentration. The end result as Maui mentioned is buyer beware.

 

[EdStainless]

You can't have something in the steel that makes it a different grade, but other than that you only need to report he listed elements and make the required properties.
ASTM is consensus organization, the users have as much say as the producers and people must agree.

P, S, Si, C, and other light elements can be lowered by treatment in melting.
Metals in the same group as Fe (V through Cu) cannot be removed or lowered other than by dilution.
The only way to get them low is start with ore and make steel without scrap.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[bobjustbob]

The paper you are referencing was presented by a salesman for PMI equipment. I like the Niton XRF analyzer and it is a good tool, but that does not mean I believe everything that the salesman tells me.

In the case of cast carbon steel valve materials as specified in ASTM A216 and ASTM A352, the max amounts of residual elements are specified in the standard are are to be reported on the material test report. In the case of parts requiring the low residual levels, this should be specified on the purchase order. Any elements specified by the purchase order must also be reported on the CMTR.

There are situations where a foundry may intentionally add residual elements, Ni and Mo in particular to improve mechanical properties. In a job shop foundry heats are made up of a number of different kinds of parts. Internal chemistry ranges are typically much tighter than the ASTM standard. WCC, WCB, LCC and LCB can all be poured from the same chemistry. Some parts may have mechanical properties that require higher impact requirements. Adding some Ni or Mo below the maximum specified level can improve these properties. So, if I am building a heat, I have to consider the chemical requirements, casting weights, molding, pouring and core making capacities and delivery requirements. To be most efficient and meet delivery I may need to pour some WCC, LCC and an LCC with high impact properties together. If I add a bit of Ni or Mo and lower the carbon to balance the carbon equivalent I can pour all of these parts on the same heat meeting all chemical and mechanical properties.

If a part needs the low residual chemistry, that restricts the foundries flexibility and requires more careful scrap selection and therefor will cost more to produce.

 

[WKTaylor]

Tmoose... Hmmmm...

In Your attachment, the table/flag notes [extracted from ASTM A29 Standard Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought] discussed most of the trace elements you mentioned... but with an over-arching statement, roughly.... 'xx to be as specified by customer and agreed by vendor/supplier'...

Since You are discussing typical/standard commercial carbon steels [A26] there should be a very important MATERIALS purpose for specifying 'clean carbon steel' in the procurement... with the added burden of cost/schedule for purity, analysis and certification.... ‘as specified by customer and agreed by the supplier’. Otherwise You can get [barely] what the base spec allows on delivery. Perhaps an aerospace grade would be a wiser choice than a commercial grade.

IF trace elements could have an important affect on Your product, then You have to specify elemental limits as part of the contract with a reputable supplier.

An old aerospace fastener/materials engineer once told me... and I have never forgotten... “You deserve to get what you ask for: but if You don’t ask for very much, don’t-expect to get very much.” --R. Nelson, XXXXXX engineer.

Or... as TheTick phrased that same sentiment this way... “You don't get what you want. You get what you ask for. Ask carefully!” –-TheTick, Eng-Tips

Did You get what You ASKED FOR?


Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[EdStainless]

You may not get what you asked for, but you never get more than you ask for....

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[racookpe1978]

You may not get what you asked for, but you never get more than you ask for....

But, post neutron activation radiation "detects" even tiny amounts of "some" trace metals and isotopes. Co60 radiation is one of the nasty unintended consequences - the trace cobalt isotopes from Inconel core fuel supports and Stellite hardened valve seat passed through the reactor cores, were activated by the neutron flux, and contaminated pipe internals with the very radioactive, very high energy Co60 deposits.

"You may get (bad things) from what you don't ask for."

But nuclear grade components ARE very expensive BECAUSE they do require such VERY EXPENSIVE metal documentation. Preventing those unintended consequences from unknown bad things is one of the primary reasons the nuclear industry is pricing itself out of its own market.

 

[WKTaylor]

EdS...

"You may not get what you asked for, but you never get more than you ask for."

... I just added this quote into my file-of-quotes/mottos/saying/etc, credit to You!

PS: in my signature block... 'Trust - But Verify!'

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[WKTaylor]

Actually Ed... mea-culpa...

I slightly reworded Your Quote for my file, thus...

You may not get what you asked for... but [for sure!] you never get more than you ask for!” –EdStainless, Eng-Tips

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

Or more succinctly:
"If you don't ask, you don't get"

 

[Tmoose]

We asked for 1045, minimum BHN 170.

The attached image shows what ASTM A29 says hot wrought 1045 "is", as well as what we "got" .