GB/T 1231-2024 Heavy Hex Structural Bolts, Single Piece (EN 14399-3 HR, formerly GB/T 1228-2006)
SKU Matrix
53 SKUs| SKU | Size (Dia × Len) | Material / Finish | Threading | Pitch | Unit Wt (g) | Action | |
|---|---|---|---|---|---|---|---|
| HB-001538 | M12×30 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 1.75 | 42 Estimated | Request a Quote | |
| HB-001539 | M12×35 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 1.75 | 47 Estimated | Request a Quote | |
| HB-001540 | M12×40 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 1.75 | 51 Estimated | Request a Quote | |
| HB-001541 | M12×45 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 1.75 | 55 Estimated | Request a Quote | |
| HB-001542 | M12×50 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 1.75 | 60 Estimated | Request a Quote | |
| HB-001543 | M12×60 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 1.75 | 69 Estimated | Request a Quote | |
| HB-001544 | M12×70 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 1.75 | 78 Estimated | Request a Quote | |
| HB-001545 | M12×80 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 1.75 | 86 Estimated | Request a Quote | |
| HB-001546 | M16×40 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 2.0 | 98 Estimated | Request a Quote | |
| HB-001547 | M16×45 | Alloy Steel· 10.9S· Black Oxide | Partially Threaded | 2.0 | 110 Estimated | Request a Quote |
Unit weight is a geometric estimate (base metal, coating excluded; HDG ≈ +4.5%); trade settlement by actual weight.
Key Parameters
Standard Basis
GB/T 1231-2024
Common equivalents are listed below; confirm dimensions and drawing details before substitution.
Spec Range
M12–M30 · 53 sizes / 53 SKUs
Alloy Steel; Black Oxide
Grades
10.9S
Confirm grade together with mating nuts, washers and certificate requirements.
What to include
Quoted by full spec
Send diameter, length, property class, material and finish with your inquiry. A standard number alone (DIN/ISO/GB) also works, we confirm the equivalent dimensions before quoting.
Standard Equivalents
Cross-referenced equivalents, order to the primary standard
| Standard | Fit | Remark |
|---|---|---|
| GB/T GB/T 1231-2024 | Identical family | Primary standard from source content |
| ISO ISO 7412 | Commercial equivalent | Common commercial equivalent; confirm heavy hex dimensions on order |
| DIN DIN 6914 | Commercial equivalent | Common commercial equivalent; confirm heavy hex dimensions on order |
This is the GB/T 1231-2024 heavy hex structural bolt product page. GB/T 1231-2024 is the current Chinese standard — it replaces GB/T 1228-2006 (heavy hex structural bolts), withdrawn on 2025-04-01 with its content merged in full into this standard; we now supply single pieces to GB/T 1231-2024 and no longer take orders against the withdrawn number. It covers heavy hexagon head high-strength bolts used in structural steelwork — a high-strength bolt with an enlarged across-flats head (single piece). DIN 6914 (German) and ISO 7412 (international) are the same-family heavy hex bolt standards, registered as equivalents in our standard-alias registry.
Relationship to EN 14399: EN 14399 is a European standard for high-strength structural bolting assemblies for preloading — a set of bolt + nut + washer, not a single bolt. It consists of several parts (e.g. -3 HR hexagon bolt and nut assemblies, -4 HV, -10 HRC calibrated-preload tension-control bolts). EN 14399-3 (System HR) covers hexagon bolt and nut assemblies whose bolt dimension system matches the GB/T 1231-2024 (formerly GB/T 1228) heavy hex bolt. We supply single pieces to GB/T 1231-2024, with set requirements confirmed per drawing, and we do not claim to provide EN 14399-certified complete connection sets. For non-preloaded connections, see EN 15048 non-preloaded structural bolting assemblies.
Why preloaded sets must be matched: a preloaded joint is tightened by stretching the bolt to create preload, which requires the bolt, nut and washer to be matched from the same batch with a consistent torque coefficient — mixing bolts and nuts from different batches or suppliers scatters the torque coefficient and makes the preload uncontrollable. This is the single most important point for buyers. We supply single pieces; if you need a complete assembly (same-batch matching, consistent torque coefficient), confirm it per project and drawing.
Sizes made to order cover M12–M30 (partially threaded, all property class 10.9S); alloy steel, black oxide finish. M36 and class 8.8 are not covered, and unlisted sizes are quoted to your drawing. For general-purpose hex bolts, see GB/T 5783 / DIN 933 hex bolts.
Spec Notes
- Sizes made to order: M12, M16, M20, M24, M30 (partially threaded), lengths about 30–240 mm
- Property class: all 10.9S (alloy steel, quenched and tempered)
- Finish: black oxide; other coatings quoted on request
- M36 and class 8.8 not covered; we supply single pieces with set requirements confirmed per drawing, and unlisted sizes quoted to your drawing
Standard Comparison
Cross-references are parameter-level only, order to the primary standard and drawing.
| GB/T 1231-2024 (CN, formerly GB/T 1228) | EN 14399-3 (EU) | DIN 6914 (DE) | ISO 7412 (ISO) | |
|---|---|---|---|---|
| Standard system | Chinese GB | European EN | German DIN | International ISO |
| Scope | Single bolt (heavy hex head) | Bolting assembly (preloaded, System HR) | Single bolt (heavy hex head) | Single bolt (heavy hex head) |
| Relation to this site | Primary | Bolt component by size basis | Equivalent | Equivalent |
| Ordering basis | Supplied to GB/T 1231-2024 | Set requirements confirmed per drawing | Confirm heavy hex dimensions | Confirm heavy hex dimensions |
FAQ
What is the relationship between EN 14399 and GB/T 1231-2024 (formerly GB/T 1228)?+
EN 14399 is a European standard for high-strength structural bolting assemblies for preloading — a set of bolt + nut + washer (parts such as -3 HR, -4 HV, -10 HRC), not a single-bolt standard. GB/T 1228-2006 was the single heavy hex head high-strength structural bolt standard; it was withdrawn on 2025-04-01 with its content merged in full into the current GB/T 1231-2024. The EN 14399-3 (System HR) bolt component is a heavy hex bolt whose dimension system matches GB/T 1231-2024 (formerly GB/T 1228); we supply single pieces to GB/T 1231-2024.
Can you supply complete EN 14399 connection sets?+
We do not claim to provide EN 14399-certified complete connection sets. We supply single pieces to GB/T 1231-2024; if you need a complete assembly (bolt + nut + washer matched to your drawing, same-batch matching, consistent torque coefficient), confirm it per project and drawing.
Do you have M36?+
No. Sizes made to order cover M12–M30; M36 is not covered. For M36, quote to your drawing.
Can class 8.8 replace 10.9S?+
No — do not downgrade. Class 10.9S has a nominal tensile strength of 1000 MPa versus 800 MPa for 8.8 (GB/T 3098.1). Preloaded structural joints must be supplied to the specified class, and every SKU in this size range is 10.9S with no 8.8. Confirm the class against your design and drawing.
What is the minimum order quantity (MOQ)?+
Confirmed per inquiry by spec and quantity; MOQ varies by size, material and finish. Send your full spec and we will quote.
Certification & Inspection
This block only lists what the standard requires the buyer to verify on order; it is not a claim that our products hold any third-party certification.
Verify on order:
- Material certificate (alloy steel grade)
- Property class (10.9S and the mating nut class)
- Coating and finish requirements (including salt-spray testing)
- Thread accuracy and dimensional tolerances (heavy hex across-flats)
For a complete assembly (bolt + nut + washer matched from the same batch) or CE / DoP / MTC 3.1 certificates, specify at order and we will assess against your project requirements separately.
Product tech package
Download the product tech package
The technical files on this page are bundled into one zip — enter your email to get it.
This package contains 4 items
- Product specification & dimension sheet (M12–M30, single piece)
- MTC / EN 10204 reading guide
- Salt spray & coating test methods
- Receiving inspection checklist (39 items)
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