1. Kev tsim thiab kev tsim cov yeeb nkab steel seamless tuaj yeem muab faib ua cov kav dej kub dov, cov kav dej txias, cov kav dej txias, cov kav dej extruded, thiab lwm yam raws li cov txheej txheem ntau lawm. 1.1. Kub dov seamless kav feem ntau yog tsim los ntawm cov yeeb nkab tsis siv neeg dov. Cov...
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