автомобилестроение крепежные изделияZ
Grade 8.8 to 12.9 fasteners and CNC machined components for chassis, powertrain, EV battery systems and interior assemblies. Every batch ships with an EN 10204 3.1 material certificate and documented torque tension data.
Automotive Fastener Applications by Subsystem
Six vehicle subsystems, six different failure modes. We map each joint to the correct grade, coating and locking method before quoting, because the same bolt specification does not transfer between a suspension arm and a door trim clip.
Chassis and Suspension
Road vibration relaxes preload until the joint fails in fatigue.
10.9 and 12.9 microalloy steel with nylon locking insert or pre applied threadlocker.
Typical parts Hex flange bolts DIN 931, nyloc nuts ISO 7040, wave washers, ball joint pins
Powertrain and Engine Assembly
Torque scatter from variable coating friction causes uneven clamp load across a cylinder head.
Controlled friction coatings with documented coefficients, plus batch level material traceability.
Typical parts Cylinder head bolts and studs, con rod fasteners, oil pan bolts, flywheel bolts
EV Battery Tray and Chassis
Heavy battery enclosures need stable joints without adding weight or allowing current path issues.
Aluminium compatible anti loosening solutions and CNC machined mounting and sealing brackets.
Typical parts Battery tray brackets, machined spacers, aluminium insert bolts, cover fasteners
Body and Structural Fastening
Self drilling screws in thin sheet distort thread torque and crack the panel.
Thread forming geometry matched to sheet gauge, with zinc nickel for extended corrosion protection.
Typical parts Hexagon flange screws, self drilling fasteners, rivet nuts, blind rivets
Brake and Steering Systems
Safety critical joints cannot tolerate any deviation from the specified preload.
Full material certificates, dimensional inspection reports and lot level traceability on every drum.
Typical parts Brake caliper bolts, steering rack fasteners, suspension pins, wheel hub bolts
Interior and Trim Assembly
Visible fasteners streak, rattle or creep after repeated thermal cycling.
Aesthetic finishes with low profile heads and nylon locking to prevent panel rattle.
Typical parts Trim screws, blind rivet nuts, plastic anchors with metal inserts, u clips
Why Automotive Buyers Work with GUXIANG
We manufacture rather than trade, which means direct control over material sourcing, cold forming, heat treatment and surface finishing. Nothing is handed to a third party between the mill and your receiving dock.
Direct manufacturing control
From raw bar stock to finished fastener inside one facility. No intermediary, and no traceability break between supplier and your goods inwards record.
Grade and coating engineering
We advise on grade and finish selection rather than simply accepting the part number. Recommendations reference the failure mode and the assembly condition, not only the datasheet.
Prototype to production in one step
Custom CNC machined parts move from a single prototype to batch production without a tooling transfer, so the part you approve is the part that ships.
Flexible batch sizing
Small air freight batches and large sea freight volumes run on the same production line, so a prototype order and a repeat order come from one source.
Not sure which grade or finish fits your joint?
Send us the drawing, the standard reference or a photo of the assembly. We will come back with a recommended specification and a firm quotation, usually within one working day.
Automotive Fastener Grades and Standards
Every grade listed below is available with a material certificate. Values follow ISO 898-1 property classes and the standards named in each row.
| Класс собственности | Tensile | Yield | Typical automotive use | Стандартный |
|---|---|---|---|---|
| 8.8 | 800 MPa | 640 MPa | Body panels, interior, non structural joints | ISO 898-1, DIN 933 |
| 10.9 | 1000 MPa | 900 MPa | Chassis, suspension, powertrain fastening | ISO 898-1, SAE J429 Gr 8 |
| 12.9 | 1200 MPa | 1080 MPa | Critical structural joints and highest load cases | ISO 898-1 |
| 10B21 / 10B38 | Case hardened | Case to 58 to 64 HRC | Self drilling and sheet металлический крепежные изделияZ | SAE J403 |
| A2-70 (304) | 700 МПа | 450 MPa | Non structural, corrosion first applications | ASTM A193, ISO 3506 |
| A4-80 (316) | 800 MPa | 600 MPa | Road salt and chemical exposure zones | ASTM A193, ISO 3506 |
If your drawing specifies a grade outside this table, send us the requirement. We will confirm manufacturability, minimum order quantity and certificate type.
Standard cross reference
| Your drawing specifies | We supply | Equivalence |
|---|---|---|
| DIN 933 | Hex head bolts, full thread | ISO 4017 |
| DIN 931 | Hex head bolts, partial thread | ISO 4014 |
| DIN 912 | Hex socket head cap screws | ISO 4762 |
| SAE J429 Grade 8 | Hex cap screws | ISO 4017 Class 8.8 |
| Ford, GM or VW internal spec | Manufactured to customer drawing | Mill certificate plus PPAP support |
Surface Finishes for Corrosion and Friction Control
Coating choice decides two separate things: how long the part survives road salt, and how consistently your tightening torque behaves on the assembly line. These two requirements sometimes conflict, and the trade off should be made explicitly.
| Завершить | Corrosion class | Friction behaviour | Salt spray | Typical application |
|---|---|---|---|---|
| Цинкование | Low to medium | Variable | 24 to 72 h | Interior, non exposed parts |
| Zinc nickel | Высокий | Controlled | 400 to 800 h | Chassis, underbody |
| Dacromet / Geomet | Очень высоко | Stable | 480 to 1000 h | Body structure, exposed joints |
| Zinc flake, non electro | Очень высоко | Slightly high | 720 h and above | Off road and heavy duty |
| Горячее оживление | Очень высоко | Variable | 1000 h and above | Structural work, low volume |
| черное оксидированиеZ | Низкий | Stable | 24 h | Interior, tooling, jigs |
| Passivation, 304 and 316 | Stainless base | Variable | Not applicable | Stainless applications |
Salt spray figures depend on coating thickness, substrate and test standard (ISO 9227). Actual figures are confirmed per batch on request. Fasteners above grade 10.9 require hydrogen embrittlement control during plating, which is handled as part of our standard process.
Quality System, Certifications and Traceability
Automotive supply chains require documentation before they require samples. Below is an honest statement of what we hold today and what is currently in progress, so you can plan your supplier qualification timeline accordingly.
ISO 9001
Quality management system covering fastener manufacturing and CNC machining operations.
IATF 16949
Automotive quality management system. Certification is in progress and targeted for completion. We support supplier audits and can share process documentation during the transition.
ISO 14001
Environmental management system. Certification is in progress alongside our automotive quality system upgrade.
RoHS and REACH
Material compliance declared for supplied fasteners and machined components.
- EN 10204 3.1 material certificate
- Dimensional inspection report
- Torque tension test data
- Coating thickness report
- PPAP Level 2 and 3 on request
- Lot level traceability marking
Delivery and Trade Terms for Automotive Buyers
The four questions every automotive buyer asks before approving a new supplier, answered before you ask them.
Automotive Fastener FAQs
Answers to the questions automotive engineers and procurement teams ask most often, with specific values rather than general assurances.
What strength grade should I use for automotive applications?
Match the grade to the load case rather than to cost. Grade 8.8 covers body panels and interior joints. Grade 10.9 is the working default for chassis, suspension and powertrain connections. Grade 12.9 is reserved for the highest load structural joints and is not usually necessary below 1200 MPa, because hydrogen embrittlement risk rises sharply at that level. If your drawing specifies a grade, send it and we will confirm manufacturability and minimum quantity.
How do I prevent thread loosening under vibration?
Three mechanisms are used in practice, often combined. A nylon locking insert gives a repeatable mechanical interference fit and is reusable a limited number of times. Pre applied threadlocker adhesive gives a controlled bond and needs no additional line equipment. A double washer or wave washer arrangement restores preload lost through joint relaxation without adhesive. For chassis joints we usually recommend a nylon insert plus a defined torque value, because it can be verified with a torque wrench already on the line.
Does hydrogen embrittlement affect high strength automotive fasteners?
Yes, and it is the most common cause of delayed field failure in plated high strength fasteners. Hydrogen can be absorbed during acid pickling and electroplating, and embrittlement can appear days after assembly. Control measures include mechanical descaling instead of acid where possible, stress relief before plating, and a mandatory hydrogen baking cycle after plating. Above grade 10.9 we specify these measures on every batch and can include baking records in the documentation package.
What is the difference between Dacromet and zinc nickel plating?
Both are high performance coatings and the right choice depends on the assembly. Dacromet and Geomet are zinc flake non electro coatings with excellent salt spray performance, typically 480 to 1000 hours, and their friction behaviour is stable, which helps torque control. Zinc nickel is an electro coating with strong hydrogen embrittlement resistance and controlled friction options, typically 400 to 800 hours salt spray. Dacromet suits exposed body structure; zinc nickel suits chassis and underbody where friction control and process control matter more.
Can you supply fasteners to my own drawing instead of a standard?
Yes. We accept customer drawings and 3D models in STEP, DWG, PDF and image formats. We will return a manufacturing feasibility review covering critical dimensions, tolerance stack, material and grade, and any tooling required. For machined components we can go from a single prototype to production without a tooling transfer, so the approved sample is the production part.
Do you support PPAP documentation for automotive customers?
We can provide PPAP Level 2 and Level 3 documentation on request, including dimensional results, material certificates, functional test data and the supporting process documentation. For new customers we normally start with a sample submission and dimensional report so that your engineering team can confirm fit before committing to the full document package. Tell us your required PPAP level in the inquiry so we can scope it correctly.
What is the minimum order quantity for custom machined parts?
We accept single piece prototypes for CNC machined components, which is the normal way to start a new machined part. Production quantities depend on part size, material and machining time, and are quoted per drawing. For standard fastener items the MOQ is negotiable and depends on thread size and finish, because these are produced from stock tooling rather than custom tooling.
How do you ensure batch to batch consistency in coating and friction?
Consistency comes from controlling the process window rather than inspecting the result. We work to a defined coating specification with thickness measurement on every batch, and for torque critical applications we can specify and record the torque tension coefficient. Where a customer specifies a friction window, that requirement goes into the purchase specification so each lot is checked against it. Batch records are retained and can be supplied with the shipment documentation.
Which certifications do you hold for automotive supply?
We hold ISO 9001 and we declare RoHS and REACH material compliance. IATF 16949 and ISO 14001 are currently in progress. If your qualification process requires IATF 16949 in place before a first production order, please state that in your inquiry and we will give you an accurate schedule and share the documentation that is currently available.
Can you deliver small prototype quantities by air freight?
Yes. Small batches and prototypes ship by air freight, either to your dock or to your nominated forwarder. This applies to both стандартные крепежные детали held in stock and custom machined parts after sample approval. For repeat production we move to sea freight, which usually lowers unit cost substantially at volume. We can quote both options so you can compare total landed cost.
Send Your Drawing or Part List
One message is enough. A drawing number, a standard reference or a plain description of the joint is enough for us to start.
- Reply within 24 hours on working days
- Quotation in your currency and shipping terms
- Engineering review available for custom parts
- Small prototype batches shipped by air