1. Bolt functional qib, uas yog, qib kev ua haujlwm ntawm bolts rau steel qauv kev sib txuas, uas tau muab faib ua ntau tshaj 10 qib xws li 3.6, 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9, thiab 12.9. Cov qib kev ua haujlwm ntawm bolts rau steel qauv kev sib txuas yog muab faib ua ntau tshaj 10 qib xws li 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, thiab lwm yam. Ntawm lawv, cov khoom siv raw ntawm bolts ntawm qib 8.8 thiab saum toj no yog cov hlau tsis tshua muaj carbon hlau lossis cov hlau nruab nrab carbon thiab cov cua sov kho (quenching, tempering), sib sau ua ke hu ua high-strength bolts, thiab lwm tus tau sau npe hu ua bolts zoo tib yam. Daim ntawv qhia qib kev ua haujlwm bolt muaj ob feem ntawm tus lej, uas qhia txog qhov nominal tensile lub zog tus nqi thiab tawm los piv ntawm cov khoom siv ntsia liaj qhov rooj.

2. Cov qib kev ua haujlwm ntawm bolts rau steel qauv kev sib txuas yog muab faib ua ntau tshaj 10 qib xws li 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, thiab lwm yam. Ntawm lawv, cov ntaub ntawv raw ntawm bolts ntawm qib 8.8 thiab siab dua yog cov hlau tsis tshua muaj carbon hlau lossis nruab nrab-carbon steel. Tom qab kev kho cua sov (quenching, tempering), feem ntau hu ua bolts muaj zog, thiab lwm yam feem ntau hu ua bolts zoo tib yam. Daim ntawv qhia qib kev ua haujlwm bolt muaj ob feem ntawm tus lej, uas qhia txog qhov nominal tensile lub zog tus nqi thiab tawm los piv ntawm cov khoom siv ntsia liaj qhov rooj. Piv txwv li: ib lub bolt ntawm chav kawm ua haujlwm 4.6, nws lub ntsiab lus yog:

1. Lub nominal tensile lub zog ntawm bolt raw khoom ncav cuag 400MPa;

2. Qhov sib piv ntawm qhov muaj zog ntawm cov khoom siv ntsia liaj qhov rooj yog 0.6;

3. Lub nominal yield zog ntawm cov khoom siv ntsia liaj qhov rooj mus txog 400 × 0.6=240MPa

Cov kev ua haujlwm qib 10.9 muaj zog bolts, tom qab kev kho cua sov, tuaj yeem ncav cuag:

1. Lub nominal tensile lub zog ntawm bolt raw khoom ncav cuag 1000MPa;

2. Qhov sib piv ntawm qhov muaj zog ntawm cov khoom siv ntsia liaj qhov rooj yog 0.9;

3. Lub nominal yield zog ntawm cov khoom siv ntsia liaj qhov rooj yog 1000 × 0.9=900MPa.