Copper in 8640? Is it possible?

[CR100]

We had a lab analyzed some unknown ball joint material, and the results were rather puzzling.

The lab unidentified the material as 8640, but with .2% copper. Could this be a custom grade of material specifically for increase wear resistance?

 

[TVP]

No, this is not a custom grade with increased Cu for wear resistance. Cu can be present up to 0.35% in steels that are melted in electric arc furnaces using scrap metal as the charge. Most of the wire and bar produced in North America is melted in an EAF, so it is not unusual to see Cu in the range of 0.1-0.2% for carbon and alloy steels. See SAE J404 and J409 for more information on chemical composition limits.

 

[CR100]

Good to know. Thank you.