Txhua cov hlau tsis muaj steel hlau ntsia ntau cov qauv. Feem ntau, ib cov hlau tsis muaj steel hlau kov cov khoom siv hauv qab no.
(1) Cov qauv ua luaj li cas - xws li cov kev ntsuas yooj yim, qhov ntev ntawm qhov dav thiab kab ua rau ntawm cov hlau tsis muaj qab hau; threaded fastener khoom, nrog rau qhov yooj yim qhov ntev thiab tolerances ntawm threads, thiab cov khoom rau qhov kawg ntawm qhov externally threaded Thiab li on.
(2) Cov qauv rau cov khoom siv dag zog - xws li kev kos cov hau kev rau kev ua tau zoo thiab cov kev ua haujlwm ntawm kev ua haujlwm.
(3) Cov qauv kawm ntawm cov teeb meem tsis haum - xws li cov hom thiab cov yuav tsum tau muaj qhov tsis xws zus ntawm cov khoom;
(4) Cov qauv rau kev kho khub - nrog rau hom tshuaj kho qhov khoom thiab cov tseev kom muaj ntawm kev kho qhov chaw;
(5) Cov qauv rau kev soj ntsuam, kev kos thiab ntim ntawm txuas ntxiv - tshwj xeeb nrog rau cov kev cai ntawm cov chaw soj ntsuam, cov qib kev tsim nyog thiab cov qauv sampling, thiab cov ntsiab lus ntawm cov khoom cim thiab cov khoom ntim. Cov cai tswjfwm;