
Does this look like lead contamination?
Usually I have no (minimal at least) issues rolling out ingots, even when they are half dirty scrap. After alloying I realized I skipped the sulfuric acid step in my gold refine. Alloy is 15k gold, with roughly 60/40 Cu to Ag for the rest. Very brittle. Annealing doesn’t really help to soften. Peened after pouring, did everything as usual. Has anyone had experience with lead contamination that showed itself like this? The alloy doesn’t feel ‘soft’ more weird brittle hardness. Maybe steel contam?? Is it possible I super heated/oxygenated the original alloy? but again, has not usually been an issue for me. I remelted it multiple times, finally with the addition of 1.3% zinc. Seemed to improve slightly but working it out still isn’t acceptable. Picture is of the end, cut 3-4 mm back, more of an internal flaw that surface issue. Looks like it released copper when annealed, which has me leaning toward I made some weird transition alloys/porosity on the first over oxygenated melt. I have known .9999 gold and .9999 silver along with copper, so will try a fresh alloy but would like to figure where I went wrong. Thank you 🙏
TLDR: Somewhat experienced, but no answer for this one, is this what lead or iron contamination can look like? Thanks