Beryllium-Copper vs Chromium-Copper 1

[gski]

Currently, we are using chromium-copper for electrodes in our projection welding processes. Due to several "Quality" isssues, a question has arised about using beryllium-copper, instead. I understand that this is a more durable material, but could the lower conductivity of the beryllium-copper cause issue? Can anyone provide info on a comparison of the 2 materials.

Thank you.

 

[kenvlach]

I can't give a definite answer (probably depends upon cycle & weld material parameters), but it seems worth testing the beryllium copper. For maximum conductivity, try the ‘low beryllium’ C17500 alloy in the fully age hardened condition. Possibly, a brief delay prior to applying current to lose some heat to the workpiece would allow use of a harder Be copper alloy. Some material parameters:

Material Alloy YS, MPa Hard.,HV %IACS Thermal cond.
0.7%Cr C18500 530 125 80-85 324 W/m-K
low Be C17500 650-870 230 45-52 200 W/m-K
Be copper C17200,C17400 965-1340 360-420 22-25 105-130 W/m-K
cast “ “ C82400 965 367 18 100 est.

Notes: Properties for all alloys in precipitation hardened condition.
The 0.8%Cr C18400 alloy has approximately the same values as C18500.
‘low Be’ is 99.6Cu-0.6Be-2.5Co in HT (TH04) Temper.
Data are from MatWeb.com, ‘Copper and Copper Alloys: Compositions and Mechanical Properties,’ CDA No. 36, 12th Edn., London (1964), and Metals Handbook, Vol. 2, 8th Edn., ASM, Metals Park, OH (1964).

Please report any results.

 

[gski]

Thanks for the information...and the reply