


These guardrail splice bolts are used to fasten guardrail plates, road barrier sections, steel brackets, and supporting metal structures. The semi-round head is suitable for exposed guardrail surfaces, while the matching nut provides secure assembly from the back side of the connection.
Carbon steel is widely used for guardrail bolts because it offers dependable strength, stable processing quality, and cost-effective bulk supply for road safety projects. Stainless steel can also be supplied for applications requiring different corrosion resistance or material requirements. Available strength grades include 4.8, 8.8, 10.9, and 12.9, allowing buyers to match the bolt performance with the project load, installation torque, and mating nut requirement.

| Item | Specification |
|---|---|
| Product Type | Semi Round Head Bolt |
| Application | Guardrail connection, highway barrier fastening, construction, steel plate assembly |
| Available Standards | DIN, ANSI |
| Material | Stainless Steel, Steel |
| Listed Material Options | Carbon Steel / Stainless Steel |
| Strength Grade | 4.8 / 8.8 / 10.9 / 12.9 etc. |
| Surface Treatment | Zinc, Plain, HDG |
| Additional Finish Options | White Zinc, Yellow Zinc, Hot Dip Galvanized |
| Main Sizes | M6, M8, M10, M12, M16 |
| Thread Specifications | M3, M6, M7, M8, M10, M12, M14, M16, M18 and more options |
| Bolt Length Options | 12mm, 14mm, 16mm, 18mm, 20mm, 30mm, 35mm, 50mm, 85mm and customized lengths |
| Matching Parts | Nuts available |
| Customization | Custom logo, custom packaging, graphic customization, drawing-based customization, sample-based customization |
| Factory Location | Handan, Hebei, China |
HDG, also known as hot dip galvanizing, is the recommended finish for outdoor guardrail bolts and road barrier fasteners. It forms a protective zinc coating that helps resist rust during outdoor installation, long-term exposure, storage, and transport.
White zinc finish gives the bolt a clean and bright surface for general hardware and construction fastening. Yellow zinc finish can be selected for buyers who need a yellow passivated appearance for specific hardware channels or market preferences. Plain finish is suitable when the bolt will receive further processing or when the buyer needs an untreated surface according to project requirements.

These HDG round head guardrail splice bolts and nuts are suitable for highway guardrails, road safety barriers, bridge guardrail systems, steel plate connections, outdoor metal structures, public infrastructure projects, construction hardware, industrial supports, and equipment frames.
For highway and outdoor use, HDG guardrail bolts help improve corrosion resistance and service life. The bolt-and-nut set is suitable for road contractors, guardrail manufacturers, construction hardware distributors, steel structure fabricators, infrastructure project suppliers, and fastener wholesalers that need bulk supply in standard or customized sizes.
| Matching Fastener | Recommended Use |
|---|---|
| Hex Nuts | Standard matching nuts for guardrail bolt assemblies |
| Heavy Hex Nuts | Suitable for stronger structural fastening requirements |
| Flat Washers | Help distribute load and protect the connected surface |
| Spring Washers | Used where additional anti-loosening support is required |
| Lock Nuts | Suitable for assemblies affected by vibration or long-term outdoor use |
| Guardrail Washers | Used in road barrier and guardrail fastening systems |
| DIN934 Nuts | Common metric nut option for standard bolt matching |
| Custom Nuts / Washers | Available for project-specific guardrail bolt sets |
Products can be supplied with matching nuts and packed according to bulk project requirements. The listed single package size is 48 x 35 x 15 cm, with a single gross weight of 15.0 kg. Packaging can be arranged according to bolt size, nut matching requirements, surface treatment, order quantity, destination market, and transport method.
Common packaging options include bags, cartons, and pallets. Custom logo, custom packaging, and graphic customization are available for qualified bulk orders. Buyers can also provide drawings or samples for customized production. Bulk supply is available from Handan, Hebei, China.

Q1: What is this product used for?
A1: It is used for guardrail connection, highway barrier fastening, steel plate assembly, construction hardware, and outdoor infrastructure fastening.
Q2: What type of bolt is it?
A2: It is a semi-round head bolt supplied with matching nuts for guardrail splice applications.
Q3: What materials are available?
A3: Available material options include carbon steel and stainless steel.
Q4: What strength grades can be supplied?
A4: Available grades include 4.8, 8.8, 10.9, and 12.9 etc.
Q5: What surface treatments are available?
A5: Zinc, plain, HDG, white zinc, and yellow zinc finishes are available.
Q6: Why choose HDG finish for guardrail bolts?
A6: HDG hot dip galvanized finish provides stronger corrosion resistance for outdoor guardrails, road barriers, and long-term infrastructure projects.
Q7: What sizes are available?
A7: Main listed sizes include M6, M8, M10, M12, and M16. Other thread and length options can be customized.
Q8: Are nuts included?
A8: Matching nuts can be supplied according to the order requirement.
Q9: What standards are available?
A9: DIN and ANSI standard options are available.
Q10: Where is the factory located?
A10: The factory is located in Handan, Hebei, China.
---
Get in touch for more information, pricing, or custom requirements.