"Specialty Metal" DFARS Question

[vision007]

Situation:

I have encounter Alumel-Chromel materials, this materials composition is Nickel-Base falling within the guideline of "specialty metals" since if over 50% Nickel Alloy, Ni-Fe Alloy, or Cobalt Alloy. Yet it seem clear that Alumel-Type Kn or Chromel-Type Kp is a "specialty metals" within the DFARS 225.7002-3 specification.

Question:

Because of my understanding that Steel music wire does not constitute as "specialty metals." Would Alumel or Chromel thermocoupling wire meet the same result?

 

[kenvlach]

I don't understand why you have a question. Both Alumel® (95% nickel, 2% manganese, 2% aluminium and 1% silicon) & Chromel® (90 percent nickel and 10 percent chromium) are 'Specialty Metals' per DFARS:
"Metal alloys consisting of nickel, iron-nickel, and cobalt base alloys containing a total of other alloying
metals (except iron) in excess of 10 percent;"

Per ASTM A228, "Steel Wire, Music Spring Quality," music wire is basically a high quality, cold drawn, high carbon (0.70-1.00% C) steel. Per Table 2 Chemical Requirements, all alloying concentrations are lower than those given below for steel to be considered a 'Specialty Metal.'

DFARS 'Specialty Metal'
"Steel—
(A) Where the maximum alloy content exceeds one or more of the following limits: manganese, 1.65 percent; silicon, 0.60 percent; or copper, 0.60 percent; or
(B) That contains more than 0.25 percent of any of the following elements : aluminum, chromium, cobalt, columbium, molybdenum, nickel, titanium, tungsten, or vanadium;"

DFARS 'Specialty Metal' compositions are given in

http://www.bis.doc.gov/DefenseIndus.../2-3-2-Reports/IronNSteelAnnexThree010902.pdf

 

[vision007]

Kenvlach,

Thanks for the rapid reply and further clarification.

RE-SUMMERIZE MY QUESTIONS

I was looking for two answers.

First, is Alumel a "Specialty Metals?"

Second, when Alumel or Chromel is use in a wire form will it still be "Specialty Metals" since my justification was that (not knowing the composition of steel music wire) will the same rule applied to Nickel Alloy based.

RESULT OF FINDING
From your response, you have addressed both of my questions but there is a inconsistence with your replied to my first question.

Chromel is a "Specialty Metals" but not Alumel.

From the DFARS guideline, "Metal alloys consisting of nickel, iron-nickel, and cobalt base alloys containing a total of OTHER alloying metals (except iron) in excess of 10 percent."

To re-word this statement for my slow thought process; if metal alloys composition of Nickel, Iron-Nickel, or Cobalt base totaling 90% or less than it is a “Specialty Metals” otherwise totaling equal or greater 90% than it is not considered as a “Specialty Metals”.

Thus here is the result of the Chromel-Alumel question:
Chromel contains 90% Nickel with 10% Chromium = “Specialty Metals”
Alumel contains 95% Nickel with 5% others = Not a Specialty Metals”

I was confused and mistakenly overlook the wording in the guideline statement of the word “other.” Well, definitely appreciate the material information and I have put way too much time into this only to find out that it was the fine print that screwed me over.

 

[vision007]

CORRECTION:

OLD
"if metal alloys composition of Nickel, Iron-Nickel, or Cobalt base totaling 90% or less than it is a “Specialty Metals” otherwise totaling equal or greater 90% than it is not considered as a 'Specialty Metals'."

NEW
If metal alloys composition of Nickel, Iron-Nickel, or Cobalt base totaling equal or less than 89% then it is a “Specialty Metals” otherwise totaling equal or greater 90% then it is NOT considered as a “Specialty Metals”.

 

[kenvlach]

Alumel® is a DFARS 'Specialty Metal' since it is a nickel-based alloy; its composition is 95% Ni, 2% Mn, 2% Al.

From DFARS link
“Specialty metals” means—
....
(ii) Metal alloys consisting of nickel, iron-nickel, and cobalt base alloys containing a total of other alloying
metals (except iron) in excess of 10 percent;"

This clause is poorly written -- I believe it means that all alloy composition < 90% iron are specialty metals.