how to calculate REM (Remainder) in chemical composition ? 1

[Rizkyffq]

Hello Guys,

May someone help me, i am really new on case like this.
So the case is that i have to make material specification about Bronze C83600, and get a standard that contains chemical requirement for Bronze C83600.

And as you see above, in Copper (CU) properties the value is stated with "REM", as i searched REM having mean "Remainder"
what is exactly REM ? is this true REM is 100% minus with all other elements ? but which value of other elements do i have take ? max or min ?

Before, many thanks

 

[mrfailure]

Remainder is simply that - the remainder. You do not need to measure a value for it as it will automatically conform regardless of value. This question is more meaningful to me when I have a specification where the base element has a specified value where I have to measure by calculating the the sum of all of the other elements found, then subtracting them from 100.

 

[EdStainless]

You do not measure or calculate it. In most product specs you simply report it as BAL (balance) or REM (remainder). But is some specs you do need to measure it because there is a requirement on 'total known alloying' to control tramp elements.
Too bad you cut the header off, I see that many of those entries are actually min/max values in adjacent entries.
You need to find the actual specification that you are trying to meet, or
The spec according to the UNS is:
Al 0.005 max
Cu 84.0-86.0
Fe 0.30 max
Ni (+Co) 1.0 max
P 0.05 max
Pb 4.0-6.0
S 0.08 max
Si 0.005 max
Sn 4.0-6.0
Zn 4.0-6.0
Cu + sum of all named elements >99.3 (this is done for tramp control)

That said most people making this material have an internal specification that has tighter ranges and has many of them off-set (not centered in the range).
When we made alloys like this our Cu+all named requirements was 99.8%


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P.E. Metallurgy, consulting work welcomed

 

Hard to do that based on ranges in a standard, because it is hazardous to assume that each element sits in the middle of its range.
If based on actual composition, it works by subtraction. Accuracy doesn't matter that much when the REM component is large, as in your example. (If it mattered, standards writers would specify hard numbers.)

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Rizkyffq]

Thanks guys for the response,
highly appreciated