欧美精品一区二区三区四区,人人摸人人操人人干人人舔,国产91清纯白嫩初高生,人妻少妇猛烈进入中文字幕图

Z 508

EZNiCu-1

Copper nickel, good machinability and bad crack resistance. Repair welding of sand hole and gray cast iron machined surface subject to no load.
鎳銅，易加工，但抗裂性較差。不受力的灰鑄鐵加工面及砂眼補(bǔ)焊

ENiCu-B

Copper alloys

銅

合

金

Cu 107

ECu

Red copper, atmosphere and sea water corrosion and excellent electric conductivity. Welding of red copper such as electrical copper row.
紫銅，耐大氣，海水腐蝕，導(dǎo)電性好。紫銅焊接用，如導(dǎo)電銅排

ECu