DACROMET BOLTS

2026-11-07 IB

1. Taw qhia

Nyob rau hauv niaj hnub engineering, bolted pob qij txha yuav tsum tiv thaiv ob qho tib si txhua yam loads thiab ib puag ncig corrosion. Cov tsoos electro-galvanizing thiab kub-dip galvanizing muab kev tiv thaiv xeb tab sis raug kev txom nyem los ntawm hydrogen embrittlement nyob rau hauv lub zog siab bolts thiab seem cuam tshuam ntawm precision threads. Dacromet txheej, zinc-aluminium flake system tsim nyob rau hauv 1970s, kov yeej cov kev txwv no. Nws muab kev tiv thaiv corrosion zoo heev, tshem tawm hydrogen embrittlement kev pheej hmoo, khaws cov xov qhov ntev, thiab muaj kev ruaj ntseg kub txog li 300 ° C. Dacromet bolts yog tam sim no dav teev nyob rau hauv tsheb, kev tsim kho, cua zog, railway, thiab marine industries.

2. Dacromet Txheej yog dab tsi?

Dacromet yog ib qho uas tsis yog-electrolytic, dej-raws li zinc-flake txheej uas muaj micron-scale zinc thiab txhuas flakes nyob rau hauv ib tug inorganic binder. Tom qab daim ntawv thov thiab kho, cov overlapping flakes tsim ib tug tuab multi-txheej barrier uas muab ob qho tib si barrier tiv thaiv thiab sacrificial cathodic tiv thaiv rau cov hlau substrate.

Cov yam ntxwv tseem ceeb:

Zaj duab xis thickness: feem ntau 5-12 μm (ntau thinner dua kub-dip galvanizing)
Cov tsos: uniform silver-grey metallic tiav
Tsis muaj hydrogen embrittlement txaus ntshai (tsis muaj kua qaub pickling lossis electrolysis)
Corrosion kuj: feem ntau> 1,000 teev ntsev tsuag rau liab xeb (ASTM B117)
High-temperature kuj mus txog 300 ° C tas mus li kev pab cuam

Cov txheej txheej yog siv los ntawm dip-spin (nruab rau cov khoom ntim ntau), tshuaj tsuag, lossis dip-drain, ces thermally kho ntawm ~ 300 ° C. Kev xaiv topcoats ntxiv txhim khu kev tiv thaiv corrosion thiab tswj cov coefficient ntawm kev sib txhuam kom zoo ib yam torque-tension kev ua tau zoo.

3. Txheej txheej txheej txheem txheej txheem

Cov txheej txheem raug rau bolts muaj plaub theem tseem ceeb:

1. Kev Npaj Nto: Alkaline degreasing ua raws li kev tu txhua yam yog tias xav tau. Acid pickling yog zam kom tsis txhob nqus hydrogen.

2.Coating daim ntawv thov: Cov khoom yog dipped nyob rau hauv aqueous zinc-aluminium flake slurry (dip-spin rau me bolts) los yog sprayed; tshaj yog tshem tawm los ntawm centrifugation rau uniform thickness.

3. Kev kho: Ci ntawm kwv yees li 300-320 ° C hloov cov binder thiab sib sau ua ke cov hlau flakes rau hauv cov txheej txheem nruj me ntsis.

4.Optional Topcoat / Sealer: Ib tug nyias sealer txhim kho lubricity, tshuaj tiv thaiv, thiab ntxiv mus ntxiv ntsev-spray kev ua tau zoo.

Vim tias cov txheej txheem no tsis yog-electrolytic thiab tsis muaj kua qaub pickling, lub zog siab bolts (Qib 8.8, 10.9, 12.9 thiab ASTM A490) tuaj yeem coated yam tsis muaj kev pheej hmoo ntawm hydrogen embrittlement - qhov tseem ceeb ntawm kev nyab xeeb zoo dua li cov tshuaj electroplating.

4. Qhov tseem ceeb ntawm Dacromet Bolts

4.1 Superior Corrosion & Anti-xeb Performance

Ib zaj duab xis Dacromet nyias (6-10 μm) ib txwm tiv taus 1,000-2,000 teev ntawm nruab nrab ntsev tshuaj tsuag ua ntej xeb liab tshwm - 7-10 npaug zoo dua li cov pa electro-galvanizing. Cov txheej txheem ntau txheej flake muab kev tiv thaiv kev tiv thaiv thaum zinc flakes xa kev tiv thaiv cathodic sacrificial. Chromate passivation ntxiv qeeb corrosion thiab muaj kev kho tus kheej ntawm cov khawb me me.

4.2 Tsis muaj Hydrogen Embrittlement

High-strength bolts yog heev susceptible rau hydrogen embrittlement los ntawm acid pickling thiab electroplating, uas yuav ua rau ncua sij hawm brittle puas. Dacromet tshem tawm qhov kev pheej hmoo no tag nrho. Yog li ntawd nws yog qhov zoo dua rau qhov tseem ceeb ntawm cov khoom siv hluav taws xob tseem ceeb hauv cov tsheb cav, chassis, cov qauv hlau, thiab cov rooj sib tham txog kev nyab xeeb.

4.3 Dimensional Accuracy & Xov Haum

Nrog lub thickness ntawm tsuas yog 5-12 μm, Dacromet tsis cuam tshuam cov xov geometry. Cov txiv ntoo txheem tuaj yeem siv tsis dhau tapping. Nyob rau hauv sib piv, kub-dip galvanizing (40-80 μm) feem ntau yuav tsum tau tshwj xeeb ceev. Cov txheej txheej nyias nyias no yog qhov zoo tagnrho rau qhov tseeb bolts thiab nplua-pitch fasteners.

4.4 Kub-kub tsis kam & tswj kev sib txhuam

Dacromet tseem ruaj khov mus txog 300 ° C txuas ntxiv kev pabcuam, deb tshaj qhov txwv ntawm electroplating (~ 120 ° C) lossis kub-dip galvanizing (~ 200 ° C). Nrog rau qhov tsim nyog topcoats cov coefficient ntawm kev sib txhuam tuaj yeem tswj tau (feem ntau μ = 0.10-0.18), kom ntseeg tau tias muaj kev sib txuam sib luag thiab txhim khu kev qha ntau tus cwj pwm nruj.

5. Kev sib piv kev ua haujlwm

Cov lus hauv qab no qhia txog qhov sib txawv tseem ceeb ntawm Dacromet thiab cov kev kho mob ib txwm siv rau bolts:

Performance Metric	Dacromet	Electro-galvanizing	Kub-dip Galvanizing
Hom Thickness	5-12 m	5-15 hli	40-80 + m
Salt Spray (rau liab xeb)	1,000–2,000+ h	100-300 hnub	500-1,000 h
H₂ Embrittlement Risk	Tsis muaj	Siab (yuav tsum tau ci)	Nruab nrab
Max Nruam Temp.	≈ 300 ° C	≈ 100-120 ° C	≈ 200 ° C
Xov Interference	Tsawg kawg / Tsis muaj	Tsawg	Qhov tseem ceeb
Siab zog Bolts	Zoo heev (8.8–12.9)	Txwv / Risky	Txwv tsis pub
Qhov tshwm sim	Uniform silver-grey	Ci los yog xiav zinc	Rough, npub grey

Table 1: Sib piv kev ua tau zoo ntawm kev kho cov ntsia liaj qhov rooj

Dacromet muaj kev sib xyaw ua ke ntawm cov yeeb yaj kiab nyias, kev tiv thaiv corrosion tsis zoo, xoom hydrogen embrittlement kev pheej hmoo, thiab muaj peev xwm kub-ua rau nws nyiam rau ntau daim ntawv thov fastener.

6. Cov ntawv thov ib txwm

Dacromet-coated bolts yog siv dav hauv qhov chaw tiv thaiv corrosion, kev nyab xeeb, thiab qhov loj me yog qhov tseem ceeb:

Automotive & Tsheb thauj mus los: Cav, chassis, ncua kev kawm ntawv thiab lub cev fasteners (tshwj xeeb yog Qib 10.9/12.9).
Cua Zog & Lub Zog: Ntauwd, nacelle thiab foundation bolts nyob rau hauv ntug hiav txwv dej los yog industrial atmospheres.
Railway & Infrastructure: Taug qab fasteners, txuas hniav thiab cov qauv kev sib txuas uas yuav tsum tau ua haujlwm ntev.
Kev tsim kho & steel qauv: High-strength structural bolts qhov twg galvanizing yog undesirable.
Marine & Offshore: Cheebtsam raug rau ntsev tsuag thiab high humidity (feem ntau nrog txhim kho topcoats).
Agricultural & Khoom hnyav: Machinery ua hauj lwm nyob rau hauv corrosive av los yog sab nraum zoov ib puag ncig.

7. Cov qauv tsim nyog & Cov Txheej Txheem Kev Xaiv

Dacromet thiab zoo li zinc-flake coatings yog them los ntawm thoob ntiaj teb cov qauv nrog rau ISO 10683 (Fasteners - non-electrolytically siv zinc flake coatings), EN 13858, ASTM F1136 / F1136M, thiab ntsev-txheej txoj kev ASTM B117 / ISO 9227.

Thaum qhia txog Dacromet bolts, engineers yuav tsum xav txog:

Qib Qib: Zoo tagnrho rau 8.8 thiab siab dua; Feem ntau yuav tsum tau ua rau 10.9/12.9 qhov chaw nyab xeeb-tseem ceeb.
Corrosion Class: Xaiv txheej hnyav, tus naj npawb ntawm cov tsho loj thiab cov tsho sab saum toj raws li xav tau ntsev-txhaj tshuaj los yog kev ntsuas kev ua haujlwm cyclic.
Kev sib txhuam coefficient: Qhia meej txog cov tshuaj tiv thaiv-lubricity topcoat yog tias qhov kev sib txuas ua ke yog qhov tseem ceeb.
Ib puag ncig: Zoo heev rau kev lag luam, tsheb thiab ntau qhov chaw sab nraum zoov; soj ntsuam cov txheej txheem thicker rau huab marine raug.
Nqi vs. Lub neej-Cycle: Cov nqi tsev siab dua li cov zinc plating feem ntau yog offset los ntawm kev pab lub neej ntev thiab kev saib xyuas qis dua.

8. Cov lus xaus

Dacromet bolts sawv cev rau kev paub tab, kev ua haujlwm siab rau kev tiv thaiv corrosion ntawm fasteners. Cov txheej zinc-aluminium flake txheej muab cov ntsev-txhaj tshuaj tiv thaiv deb tshaj li cov pa electro-galvanizing, tshem tawm cov hydrogen embrittlement kev phom sij uas ua rau muaj zog bolts, khaws cov xov zoo meej, thiab tiv taus qhov kub siab txog 300 ° C.

Rau cov kws tsim khoom thiab cov neeg yuav khoom nrhiav kev txhim khu kev qha los tiv thaiv xeb thiab tiv thaiv corrosion hauv tsheb, qauv, lub zog thiab kev lag luam, Dacromet-coated bolts muab pov thawj qhov sib npaug ntawm kev ruaj ntseg, kev nyab xeeb thiab kev ncaj ncees. Thaum tau teev tseg kom raug - sib piv cov qib txheej, topcoat thiab cov khoom sib txhuam rau qhov chaw pabcuam - lawv ua rau lub neej ntev dua, txo kev txij nkawm thiab txhim kho tag nrho cov kev ntseeg tau. Raws li qhov xav tau kom muaj zog dua, cov khoom siv ntev ntev txuas ntxiv zuj zus, zinc-flake coatings xws li Dacromet tseem yog lub hauv paus ntawm niaj hnub fastener nto engineering.

Ua ntej. Tom ntej no.

Xov xwm tshiab