Lub bolts rau cov qauv siv hlau txuas yog muab cais ua ntau tshaj li 10 qib ntawm 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, thiab lwm yam., Uas cov xaum qib 8.8 thiab saum toj no yog ua los ntawm cov qes qis hlau lossis nruab nrab carbon steel thiab cua sov kho. (Quenching, tempering), feem ntau hu ua high-strength bolts, tus so yog feem ntau raug xa mus rau raws li ordinary bolts. 10.9 lub bolts yuav tsum muaj qhov sib zog tho loj. Ntxiv nrog rau qhov yuav tsum tau muaj zog, ib qho tseem ceeb qhia tau yog qhov tshwm sim ntawm qhov teeb meem toughness. Feem ntau, nws yog ib qho yooj yim kom ua tiav qhov dag zog ntawm kev lag luam, thiab nws yog qhov nyuaj rau qhov feem cuam toughness index. Kuv tus kheej kev paub yog tias 40Cr, 35CrMo yog tsim rau 8.8 los yog tsawg dua, 42CrMo yog tsim rau 8.8 bolts, thiab bolts saum 10.9 yuav tsum yog 34CrNiMo los yog 34CrNi3Mo.
