Kedu ihe eji ebu ihe kacha mma maka ngwa m: alloy steel, aluminum, igwe anaghị agba nchara, ma ọ bụ nchara alloy? Ọtụtụ ihe nwere ike imetụta mkpebi ịzụrụ ngwongwo ibu, dị ka ọnụ ahịa, ngwa nha (dịka ọmụmaatụ, nha ihe, ịdị arọ ihe, ntinye ihe), ịdịte aka, gburugburu ebe obibi, wdg. Onye ọ bụla n'ime ha ...
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