Qib 8.8 Hex Bolts

2026-08-03 IB

1. Qib 8.8 — Nruab nrab-High Strength Fastener Class

1.1 Decoding lub 8.8 Tsim

Cov cim "8.8" yog cov khoom siv hauv chav kawm tsim los ntawm ISO 898-1, tus txheej txheem thoob ntiaj teb tswj hwm cov khoom siv ntawm cov pa roj carbon steel thiab alloy steel fasteners. Ob tug lej system encodes ob qhov tseem ceeb mechanical parameters:

● Thawj tus lej (8): Qhia txog ib feem kaum ntawm lub zog tensile nominal hauv megapascals → 8 × 100 = 800 MPa lub zog tensile yam tsawg kawg nkaus.

● Tus lej thib ob (.8): Sawv cev rau qhov piv txwv → 0.8 × 800 = 640 MPa yam tsawg kawg nkaus yield zog.

Qib 8.8 fasteners yog cov khoom siv dav dav dav siv thoob ntiaj teb, npog hex bolts, hex cap screws, carriage bolts, stud bolts, thiab tag nrho threaded screws rau steel siv, tsheb sib dhos, thiab cov tshuab dav dav.

Daim duab 1. Qib 8.8 hex bolts nrog cov khoom siv hauv chav kawm

1.2 Mechanical Properties

Qib 8.8 fasteners yog tsim los ntawm nruab nrab carbon steel thiab undergo quenching thiab tempering (Q&T) kom ua tau raws li qhov yuav tsum tau ua txhua yam kev ua tau zoo. Cov yam ntxwv tseem ceeb ntawm ISO 898-1:

Khoom	Tus nqi	Chav tsev
Yam tsawg kawg Tensile Strength (Rm)	800	MPa
Yam tsawg kawg Yield Strength (ReL)	640	MPa
Tsawg kawg Elongation tom qab Fracture	≥ 12	%
Core Hardness (HV)	250–310 : kuv	HV
Yam Q&T Hardness (HRC)	22–32 : kuv	HRC
Nominal Bolt Diameter Range	M5 – M39	mm

Table 1. Cov khoom tseem ceeb ntawm Qib 8.8 fasteners rau ISO 898-1

1.3 Cov ntaub ntawv pom zoo

Xaiv cov khoom raw yog lub hauv paus ntawm kev tsim cov qib 8.8 fasteners txhim khu kev qha. Cov hlau hauv qab no, ua ke nrog Q&T kom raug, ua tiav qib 8.8 kev ua tau zoo:

● 35# Medium-Carbon Steel — haum rau me me-inch fasteners (≤ M16). Nqi-zoo, txaus hardenability tom qab Q&T.

● 45# Medium-Carbon Steel - Qhov kev xaiv nrov tshaj plaws rau Qib 8.8 hex bolts thiab stud bolts. Zoo machinability, ruaj khov mechanical zog tom qab Q&T.

● 40Cr Alloy Steel - Nyiam rau cov ntsia hlau loj dua (M20+). Chromium ntxiv txhim kho hardenability thiab tensile uniformity hla ntu ntu.

1.4 Qib sib piv

Qib	Tensile (MPa)	Tawm tswv yim (MPa)	Cov ntaub ntawv pom zoo
4.6	400	240	Tsawg carbon steel, tsis-kub-kho
4.8	420	340	Tsawg carbon steel, ua haujlwm txias
8.8	800	640	35 # / 45 # Carbon Steel, 40Cr Alloy Steel; Q&T
10.9	1,040	940	40Cr, 35CrMo, 42CrMo, SCM435; Q&T
12.9	1,220	1,100	42CrMo4 / SCM440, 35CrMoV; Q&T 39–44 HRC

Table 2. Cov chav kawm cov cuab yeej fastener thiab cov ntaub ntawv pom zoo

2. Hex Bolts - Cov Khoom Siv Tau Zoo Tshaj Plaws

2.1 Hex Bolt yog dab tsi?

Hex ntsia liaj qhov rooj (hexagonal taub hau ntsia liaj qhov rooj) yog ib tug threaded fastener nrog ib tug rau-sided lub taub hau, tsim los muab tso rau hauv lub qhov nyob rau hauv sib dhos qhov chaw thiab ruaj los ntawm ib tug mating txiv ntseej. Lub hexagonal geometry tso cai rau cov ciaj ntswj los yog lub qhov (socket) kev koom tes los ntawm ntau lub kaum ntse ntse, ua rau nws siv tau zoo tshaj plaws thiab siv hom ntsia liaj qhov rooj thoob plaws txhua qhov kev lag luam. Muaj ob lub ntsiab variants:

● Hex Bolt (ISO 4014 / DIN 931) - Ib feem threaded: ib feem ntawm cov shank unthreaded muab lub zog shear thiab kev sib raug zoo, zoo tagnrho rau cov qauv kev sib txuas.

● Hex Cap Screw (ISO 4017 / DIN 933) - Ua tiav threaded: threads khiav tag nrho ntev, haum rau cov ntawv thov uas xav tau kev sib koom tes ntau tshaj plaws.

Daim duab 2. Anatomy ntawm ib tug hex bolt — cov yam ntxwv tseem ceeb

2.2 Hom Hex Bolt Hom & Variants

● Hex Head Bolt / Cap Screw - Txheem rau lub taub hau; feem ntau ntau yam, siv nyob rau hauv kev tsim kho, machinery, automotive.

● Hex Flange Bolt — Integrated washer-zoo li flange nyob rau hauv lub taub hau; faib clamp load, tshem tawm cov tshuab ntxhua khaub ncaws.

● Heavy Hex Bolt (ASTM A325) - Lub taub hau loj dua rau kev sib txuas steel hlau; teev nyob rau hauv North American cov qauv.

● Hex Lag Bolt / Carriage Bolt - Tshwj xeeb txawv rau kev sib txuas ntawm ntoo-rau-steel thiab ntoo.

2.3 Qhov Loj & Qhov Loj

Loj	Suab	Ntsia hlau	Lub taub hau.	Lub taub hau ht.	Shank dia.	Ntev Ntau
M6	1.0	10 mm	10.0	4.0	6.0	16–60 : kuv
M8	1.25	13 hli	13.0	5.3	8.0	20–80 : kuv
M10	1.5	16 mm	16.0	6.4	10.0	25–100 : kuv
M12	1.75	18 mm	18.0	7.5	12.0	30–120 : kuv
M16	2.0	24 mm	24.0	10.0	16.0	40–150 : kuv
M20	2.5	30 mm	30.0	12.5	20.0	50–200
M24	3.0	36mm ib	36.0	15.0	24.0	60–240 : kuv

Table 3. Qib 8.8 hex ntsia liaj qhov rooj qhov ntev ntawm ISO 4014 / ISO 4017

3. Qib 8.8 Hex Bolts — Xaiv & Daim Ntawv Thov

3.1 Kev Kho Hniav

Kev xaiv kev kho deg nyob ntawm qhov chaw ua haujlwm thiab kev tiv thaiv corrosion. Cov kev xaiv dav dav rau Qib 8.8 hex bolts suav nrog:

● Zinc Plating (Electroplated) - Economical, nruab nrab corrosion kuj; txheem xaiv rau sab hauv tsev thiab ib puag ncig me me.

● Kub-Dip Galvanizing - tuab zinc txheej rau sab nraum zoov thiab marine raug; yuav tsum tau oversize tapped ceev.

● Dacromet Txheej - Chromium-dawb, txheej txheem kev phooj ywg ib puag ncig; superior ntsev-txhaj tshuaj tiv thaiv tsis muaj hydrogen embrittlement txaus ntshai. Zoo tagnrho rau kev siv tsheb thiab cov qauv siv.

● Ruspert Txheej - Peb txheej organic/zinc composite; zoo heev weatherability, feem ntau teev nyob rau hauv Japanese cov qauv kev lag luam.

3.2 Kev taw qhia kev teeb tsa

● Siv cov qhab nia qib 8 sib piv rau cov xov lub zog sib xws.

● Siv cov txheej txheem nruj nruj ntawm cov chaw tsim khoom cov ntaub ntawv; over-tightening txaus ntshai bolt tsis ua haujlwm.

● Lubricate threads ua ntej daim ntawv thov torque — kev sib txhuam coefficient ho cuam tshuam ua tiav ua ntej load.

● Xyuas kom tseeb tias tsawg kawg yog ib txoj xov tag nrho protrudes tshaj lub ntsej muag txiv ntseej tom qab zawm.

● Tsis txhob rov siv dua qib 8.8 bolts hauv kev sib txuas ntawm cov qauv tseem ceeb tom qab ua ntej lub zog tag nrho.

3.3 Cov Qauv & Ntawv Pov Thawj

Qib 8.8 hex bolts yog tsim thiab sim raws li:

TS EN ISO 898-1 - Cov khoom siv ntawm cov hlua khi ua los ntawm cov hlau thiab hlau alloy.

● ISO 4014 - Hex bolts nrog ib nrab threaded shank (qhov ntev).

● ISO 4017 - Hex cap screws nrog cov xov tag nrho (qhov ntev).

● Daim ntawv pov thawj cov khoom siv tag nrho (MTC) raws li EN 10204 3.1 muaj nyob rau thaum thov.

Ceev Reference

Qib	Cov ntaub ntawv pom zoo	Hom Khoom Siv	Kev kho cua sov
8.8	35 # / 45 # Carbon Steel 40Cr Alloy Steel	Hex Bolt, Hex Cap Screw, Carriage Bolt, Stud Bolt	Quenching & Tempering