Fabbrica di bulloni esagonali in acciaio inossidabile A4-70
XZ Fastener supplies A4-70 stainless steel hex bolts for industrial buyers who need dependable corrosion resistance, clear specifications, and export-ready packing. These external hex fasteners are commonly ordered as DIN 933 full thread hex bolts, ISO 4017 metric hex head bolts, DIN 931 partial thread bolts, or drawing-based parts according to project requirements. A4-70 is suitable for many marine, outdoor, chemical equipment, and machinery assemblies where 316-family stainless steel is preferred over carbon steel. Buyers can source bulloni esagonali in acciaio inossidabile with size lists, material documents, matching nuts and washers, and inspection details confirmed before production.
Norma
DIN 933 / ISO 4017 filettatura completa; DIN 931 / ISO 4014 opzionale
Forza
A4-70, with A4-80 available upon request
Materiale
A4 / 316-family austenitic stainless steel
Finisci
Liscio, passivato, decapato e passivato, lubrificato
Applicazione
Marine fittings, outdoor structures, equipment, chemical plants
Cosa dovrebbero sapere gli acquirenti prima di acquistare bulloni esagonali in acciaio inossidabile A4-70
A4-70 hex bolts are often selected for corrosion resistance first and strength second. If the joint is highly loaded, exposed to vibration, or controlled by a structural standard, the bolt grade, nut grade, washer hardness, tightening method, and service environment should be checked together before purchase.
Confirm the standard first
DIN 933 and ISO 4017 indicate full thread hex bolts, while DIN 931 and ISO 4014 indicate partial thread hex bolts. XZ Fastener also supplies Bulloni a testa esagonale A2 e A4 for projects that require mixed full thread and partial thread lists.
Separate material from strength
A4 describes the stainless steel group, while 70 describes the property class. A4-70 is different from Grade 8.8 carbon steel hex bolts; the correct choice depends on corrosion exposure, joint load, and the mating material.
Check thread fit and galling risk
Stainless steel threads can gall under high assembly speed or dry tightening. For repeated assembly, buyers may request lubrication, anti-seize guidance, or a matching nut and washer set.
Descrizioni di acquisto comuni
Clear purchasing descriptions reduce confirmation time and help avoid mixed standards in the same order. Typical buyer wording includes:
- A4-70 stainless steel hex bolts DIN 933 full thread, M8 x 30, plain finish.
- 316 stainless steel metric hex head bolts ISO 4017, A4-70, passivated.
- DIN 931 partial thread A4-70 hex bolts with matching stainless nuts and flat washers.
- Stainless steel hex cap screws M6-M24, A4-70, for marine equipment assembly.
- DIN Bulloni a testa esagonale a filettatura completa 933 in carbon steel when the buyer specifies zinc plated DIN 933 bolts, black oxide DIN 933 bolts, hot dip galvanized DIN 933 bolts, or Grade 8.8 carbon steel hex bolts instead of stainless steel.
If the order combines stainless and carbon steel items, mark each line clearly with material, grade, finish, and inspection requirement.
Tabella delle specifiche dettagliate
| Articolo | Specifica | Note dell'acquirente |
|---|---|---|
| Nome del prodotto | Bulloni a testa esagonale in acciaio inossidabile A4-70 | Can be supplied as bolts only or with matching nuts and washers. |
| Standard | DIN 933, ISO 4017, DIN 931, ISO 4014, parti basate su disegno | Confirm full thread or partial thread before quotation. |
| Gamma di diametri | Common metric sizes such as M3-M36; larger sizes by order requirement | Actual range depends on standard, length, and production method. |
| Lunghezza | Lunghezze standard o lunghezze personalizzate secondo i disegni | For thread details, see this guida per la lunghezza della filettatura del bullone. |
| Filo | Filettatura metrica grossa; passo fine disponibile su richiesta | Provide pitch if the order is not standard coarse thread. |
| Materiale | A4 / 316-family austenitic stainless steel | La composizione chimica finale segue lo standard selezionato e l'ordine di acquisto. |
| Classe immobile | A4-70 con riferimento ISO 3506 | A4-80 can be discussed when higher stainless strength is needed. |
| Finitura superficiale | Liscia, passivata, decapata e passivata, lucidata, lubrificata | La finitura deve corrispondere all'esposizione alla corrosione e al metodo di assemblaggio. |
| Ispezione | Dimensions, thread gauges, visual appearance, material documents, mechanical test reports upon request | Documenti di ispezione statale prima dell'inizio della produzione. |
| Imballaggio | Bulk cartons, small boxes, pallet packing, labels, barcodes, private packing | Packaging can be arranged according to order requirement. |
Spiegazione del materiale e del grado
A4 stainless steel is a molybdenum-bearing austenitic stainless group widely used where chloride exposure, outdoor moisture, or chemical environments may attack ordinary carbon steel or lower stainless grades. A4-70 indicates a stainless property class commonly associated with a minimum tensile strength level of 700 MPa under ISO 3506 reference conditions.
For many buyers, the most important comparison is A2 versus A4. A2 is suitable for general indoor and mild outdoor applications, while A4 is typically preferred for marine air, chemical equipment, wastewater facilities, and coastal structures. For more material selection background, review XZ Fastener’s guide to Elementi di fissaggio in acciaio inossidabile A2 vs A4.
A4-70 should not be treated as a direct substitute for Grade 8.8 carbon steel hex bolts without checking load requirements. Grade 8.8 carbon steel has higher strength, while A4-70 offers better corrosion resistance in many environments.
Inspection requirements can be confirmed before production, including dimensions, thread fit, surface condition, and documents.
Guida alla selezione della finitura superficiale
Most A4-70 stainless steel hex bolts are ordered in plain stainless or passivated finish. Passivation helps remove free iron from the surface and supports the natural stainless protective layer. Pickling and passivation may be requested when welding scale, heavy oxide, or stronger surface cleaning is required.
| Finisci | When to Use | Important Note |
|---|---|---|
| Inossidabile normale | General machinery, indoor assemblies, clean stainless appearance | Economical and widely used for standard stainless fasteners. |
| Passivato | Outdoor, marine air, chemical equipment, food-related support frames | Common choice when corrosion resistance and clean surface are both important. |
| Decapato e passivato | Requisiti di pulizia delle superfici più impegnativi | Confirm appearance expectations and inspection method in advance. |
| Lubricated or anti-seize prepared | Assemblies with repeated tightening or galling concern | Torque values may change when lubrication is used. |
| Rivestimenti in acciaio al carbonio | Bulloni DIN 933 zincati, ossido nero Bulloni DIN 933, zincati a caldo DIN Bulloni 933 | These are generally carbon steel alternatives, not standard A4 stainless finishes. |
For coating comparisons on carbon steel and other fasteners, see this guida di finitura del dispositivo di fissaggio.
Produzione e controllo qualità
Production planning starts from the confirmed standard, size list, material grade, thread type, finish, packaging, and document requirements. Depending on diameter and length, A4-70 stainless steel hex bolts can be produced by cold heading, hot forging, machining, thread rolling, or thread cutting. The selected process depends on size, quantity, tolerance, and lead time.
Prima della produzione
XZ Fastener checks the purchase description, drawing, material requirement, thread pitch, finish, packing method, and inspection documents. For non-standard items, elementi di fissaggio personalizzati can be reviewed from drawings or samples.
Durante la produzione
Common control points include head dimensions, across-flat size, thread length, thread gauge fit, surface appearance, burr control, and mixing prevention between stainless grades.
Prima della spedizione
Carton labels, pallet marks, quantity, finish, and inspection documents are checked according to order requirement. Material test certificates and third-party inspection can be discussed before order confirmation.
Applicazioni
A4-70 stainless steel hex bolts are selected when buyers need a balance of corrosion resistance, standard metric dimensions, and practical assembly with wrenches or sockets. They are widely used in:
- Equipaggiamento marittimo e strutture costiere
- Attrezzature per il trattamento chimico
- Assemblaggi per esterni in acciaio e alluminio
- Sistemi di trattamento delle acque reflue
- Hardware di supporto per pompa, valvola e tubo
- Strutture di supporto per alimenti e bevande
- Solar mounting and exposed equipment frames
- Manutenzione e ricambi macchinari
For submerged seawater, strong chloride chemicals, or critical load-bearing joints, confirm the engineering requirement before selecting A4-70.
Come ottenere un preventivo più velocemente
A clear inquiry helps XZ Fastener quote the correct A4-70 stainless steel hex bolts without repeated clarification. Please provide:
- Size list, such as M8 x 30, M10 x 50, M12 x 80.
- Standard, ad esempio DIN 933, ISO 4017, DIN 931, ISO 4014 o numero di disegno.
- Materiale e qualità, ad esempio acciaio inossidabile A4-70, A4-80, A2-70 o 316.
- Requisiti di finitura, come semplice, passivato, decapato e passivato o lubrificato.
- Quantity for each size and whether partial shipment is acceptable.
- Packaging requirement, including bulk carton, small box, pallet, label, barcode, or private brand packing.
- Inspection requirements, such as MTC, dimensional report, salt spray reference, or third-party inspection.
- Destination port or delivery term if freight support is needed.
Per una richiesta strutturata, utilizzare il file richiedi un preventivo page and attach drawings or a spreadsheet if available.
FAQ
Is A4-70 the same as 316 stainless steel?
A4 is commonly associated with the 316-family stainless steel group, while A4-70 also defines a mechanical property class. The final chemical composition and mechanical values should follow the selected standard and purchase order.
Qual è la differenza tra i bulloni esagonali DIN 933 e DIN 931?
DIN 933 usually refers to full thread hex bolts, while DIN 931 usually refers to partial thread hex bolts. Buyers should confirm thread length because it affects assembly, shear area, and stock availability.
I bulloni esagonali in acciaio inossidabile A4-70 possono sostituire i bulloni esagonali in acciaio al carbonio Grade 8.8?
Not automatically. A4-70 is chosen for corrosion resistance, while Grade 8.8 carbon steel hex bolts are chosen for higher strength. The joint load, environment, and engineering requirement should be checked before substitution.
Which finish is recommended for A4-70 stainless bolts?
Plain stainless and passivated finishes are common. Passivation is often requested for outdoor, marine air, chemical equipment, and clean stainless assemblies. Lubrication may be useful when galling risk is a concern.
XZ Fastener può fornire dadi e rondelle corrispondenti?
Yes. Matching stainless hex nuts, flat washers, spring washers, and packing sets can be supplied according to the bolt material, thread, standard, and project requirement.
Quali documenti possono essere richiesti insieme alla spedizione?
Buyers may request material test certificates, dimensional inspection reports, visual inspection records, packing lists, and other documents according to order requirement. Document needs should be stated before production.
Can custom sizes or non-standard hex bolts be produced?
Custom lengths, special thread pitch, drawing-based head dimensions, markings, and packaging can be discussed. Send drawings, samples, photos, quantity, and application details for review.
Invia la tua richiesta sul bullone esagonale inossidabile A4-70
To receive a practical quotation, send your size list, finish, quantity, packaging method, and inspection requirements. Include the standard or drawing number, destination, and whether matching nuts and washers are needed. XZ Fastener will review the details and help confirm a supply plan according to your order requirement.
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