1. Raws li cov khoom siv, nws muab faib ua cov pa roj carbon steel pob qij qis, nruab nrab cov pob carbon steel pob, cov pa roj carbon steel loj, cov khoom siv loj yog 1010-1015, 1045, 1085, thiab lwm yam; 2. Raws li qhov nyuaj, nws muab faib ua cov pob muag muag thiab pob nyuaj, uas yog los txiav txim siab seb puas kho kub ...
Nyeem ntxiv