黑铅 meaning in Chinese

black lead
blacklead
graphite

Mechanical pencils . part 2 : balck leads . classification and dimensions
机械铅笔.第2部分:黑铅.分类和尺寸
The grandmother had been blackleading the stove , it was saturday morning
祖母刚把火炉用黑铅油过，那天是星期六的早晨。
When using a multimeter to check voltage , be sure you have a good ground for the black lead of the multimeter
当用万用表检查电压,你一定有好的理由万用表的黑铅