Dacromet-Coated Hex Bolts

2026-10-27

1. Nhanganyaya

Majoini ese akasungwa ihondo yekurwisa ngura. Hex bolt (hexagon head cap screw) inogona kunge iri iyo inonyanya kusungirirwa pasi rose, asi kana yangoiswa mubhiriji, shongwe yekutumira, kana makemikari chirimwa, inobva yarwiswa nehunyoro, oxygen, chloride ions, uye sulfur dioxide. Ngura - kutanga ngura chena (zinc oxidation zvigadzirwa), ipapo ngura tsvuku (iron oxide) - inokambaira nepamusoro penzvimbo inotakura, inopinda mukati meshinda, uye pakupedzisira inobata nati, inonetesa mutoro wekusungirira, uye inoparadza mubatanidzwa.

Dacromet coating (inonziwo DACROMET, zinc-flake coating, kana isiri-electrolytic zinc-aluminium flake coating) yakagadzirwa chaizvo kuti ikunde iyi hondo. Inopa hex mabhaudhi, matudhi, uye anofananidzira hex nzungu uye washer nhumbi dzakatetepa, yunifomu, hydrogen-isina iyo inorarama kupfuura maawa mazana manomwe ekuyedzwa kwemunyu wekupfapfaidza (NSS) - kakawanda kupokana kwekuora kwe electro-galvanizing pahukobvu hwakafanana.

2. Fastener Basics: Iyo Hex Bolt muBolted Joint

Hex bolt inoshanda nenzungu (kana buri rakacherwa) kusungirira zvikamu zviviri kana kupfuura pamwechete. Kutendeseka kwekubatana kunoenderana ne preload (clamp load) yakaunzwa panguva yekuomesa, iyo inodzorwa neyakaiswa torque, tambo yeshinda, uye friction coefficient (μ) pakati penzvimbo inotakura uye shinda. Mumusangano unodzorwa ne torque, mainjiniya anoshandura chinongedzo chekutanga kuita kukosha kwe torque vachishandisa iyo nut factor (K ≈ 0.12–0.16 ye lubricated zinc-flake coated fasteners).

Zvakajairwa kukwirana zvinosanganisirwa mugungano rakasungwa zvinosanganisira:

Hex bolts / hex cap screws— shinda yakazara (DIN 933 / ISO 4017) kana chidimbu cheshinda (DIN 931 / ISO 4014), kirasi yepfuma 8.8, 10.9, kana 12.9;
Hex nzungu- ISO 4032 yakajairika nzungu kana ISO 4033 nzungu dzakatetepa / jamu, kirasi inofananidzwa nebhaudhi;
Flat washers(DIN 125) uye maspring washers (DIN 127) - kugovera kutakura mutoro uye kuwedzera vibration kuramba;
Matudhi uye tambo dzakarukwa- yekubatana kweflanged uye kuburikidza-mabhoti maassembles;
Flange nuts uye flange bolts- ine akabatanidzwa anotakura maflange kune akapfava substrates.

Chimwe nechimwe chezvikamu izvi zvinofanirwa kugovera imwechete corrosion-protection system; Dacromet bolt yakabatanidzwa ne plain zinc-plated nut inogadzira a galvanic vaviri iyo inobaira nati kutanga.

3. Corrosion Resistance: Dacromet vs. Zvimwe Bolt Inopedzisa

Munyu wekupfapfaidza kutsungirira (ISO 9227 / ASTM B117, maawa kusvika kumarara tsvuku) ndiyo bhenji yeindasitiri yekudzivirira kwekudzivirira ngura.

Pedzisa / coating system	Ukobvu	Maawa ekutsvuka ngura (NSS)	White rust (NSS)	Hydrogen embrittlement	Notes
Plain (self-color, oiled)	—	<24 h	—	Hapana	Indoor kushandiswa chete
Zinc plating, blue chromate (Zn3)	5 μm	≈ 48 h	12–24 h	High	Mutengo wakaderera, zvinhu zvevatengi
Zinc plating, gobvu passivate (Zn12)	12 μm	≈ 192 h	96–168 h	High	Kwete yekirasi ≥ 10.9
Mechanical galvanizing	20–50 μm	300–800 h	200–400 h	Yakaderera kwazvo	Zvakanaka kune zvikamu zvakakura
Kupisa-dip galvanizing (HDG)	45–85 μm	500–1,500 h	200–500 h	Low	Shinda dzinoda kudzokororwa
Dacromet Kirasi 2	8 μm	≈ 720 h	300–500 h	Hapana	As-cut thread chaiyo
Dacromet Kirasi 3 / dema	10–12 μm	≈ 1,000 h	500–720 h	Hapana	Automotive OEM benchmark

Dacromet zvakare inodarika zinc plating mu Kesternich bvunzo (SO₂ corrosion, ISO 6988 - mamiriro ekunze eindasitiri uye mvura ine acid), mukati cyclic corrosion test (CCT: yakasanganiswa munyu pfapfaidzo / humidity / kuomesa), mukati galvanic kugarisana nealuminium substrates (nekuda kwealuminium flake yemukati), in tembiricha bhasikoro (iyo inorganic firimu inoshingirira 120–300°C sevhisi, apo organic coatings blister), uye mu makemikari kuramba kune munyu wemugwagwa uye makemikari ekubvisa icing.

4. Mhedziso

Kune hex mabhaudhi uye mating Hardware, Dacromet coating inopa yakanakisa chiyero chekudzivirira ngura, kurongeka kwemagetsi, uye kuvimbika kwegungano kunowanikwa nhasi: munyu wekupfapfaidza kutsungirira kusvika kumaawa e1,000, kusadzivirirwa kune hydrogen embrittlement, yakachengetedzwa tambo geometry, uye yakatsiga friction yekusangana-inodzorwa netorque. Kwese uko mubatanidzwa wakasungwa unofanirwa kurarama mvura, munyu, uye nguva, iyo yekurangarira ndeye: yakakwirira-simba hex bhauti, zinc-flake (Dacromet) yakavharwa, ISO 10683 / ASTM F1136 inoenderana.

Hauna. Next.