Hex Bolts
Hex bolts should be specified by standard, diameter, length, thread type, grade or class, material, finish, quantity, packing, and matching nut or washer requirements before RFQ review. This page supports manual sourcing communication and does not claim inventory, fixed pricing, production capacity, certification coverage, or guaranteed lead time.
Direct Answer for Buyers
For a hex bolt RFQ, buyers should first confirm whether the item follows DIN 933, DIN 931, ISO 4017, ISO 4014, ASME B18.2.1, ASTM A307, ASTM A325, ASTM A490, DIN 6914, or a buyer drawing. Full-thread and partial-thread bolts should be listed separately, and metric class or inch grade should be confirmed before price discussion.
Hex bolts are often sourced together with matching nuts, flat washers, spring washers, hardened washers, cartons, pallets, inspection documents, and coating requirements. Prices, MOQ, delivery lead time, packing details, and documentation are confirmed after manual RFQ review.
Final specifications should be confirmed according to the buyer's drawing, BOM, project standard, or RFQ requirements.
Product images are representative category references only. Final specifications should be confirmed by buyer drawings, standards, samples, or purchase lists.
Buyer Quick Answers
Short answers for commonly asked hex bolt sourcing questions.
1. What is a hex bolt?
A hex bolt is an externally threaded fastener with a hexagonal head, normally used with a nut or a tapped component. Buyers should specify the applicable standard, diameter, length, thread type, grade, material and finish per project requirements.
2. What is the difference between DIN 931 and DIN 933 hex bolts?
DIN 931 commonly refers to partially threaded metric hex bolts, while DIN 933 commonly refers to fully threaded metric hex bolts. The final choice depends on grip length, thread length, joint design and the buyer standard.
3. How do DIN 933 and ISO 4017 compare?
DIN 933 and ISO 4017 are commonly compared references for fully threaded metric hex bolts, but they must not be treated as automatically interchangeable. Buyers should confirm the edition, dimensions, tolerances, marking and project requirements before substitution.
4. How do DIN 931 and ISO 4014 compare?
DIN 931 and ISO 4014 are commonly compared references for partially threaded metric hex bolts. Exact requirements including dimensions, tolerances and project acceptance must be confirmed before substitution.
5. What is the difference between fully threaded and partially threaded hex bolts?
A fully threaded hex bolt has threads extending along most of its shank, while a partially threaded bolt includes an unthreaded grip section. The choice depends on application requirements, joint design and the specified standard. Neither type is exclusively suited for tension or shear without project-specific verification.
6. What is the difference between property classes 8.8 and 10.9?
Property classes 8.8 and 10.9 represent different metric mechanical performance levels, with 10.9 generally being the higher-strength class. The final selection should be confirmed by engineering design and the applicable standard. Buyers should not assume 10.9 is automatically suitable without project-specific review.
7. Can metric and inch hex bolts be substituted?
No. Metric and inch hex bolts are not automatically interchangeable. The thread system, diameter, pitch or TPI, length, head dimensions, grade and matching components differ between the two systems. Buyers should confirm the original specification. See the Metric and Inch Fastener Conversion Guide for reference.
8. What is the difference between carbon steel and stainless steel hex bolts?
Carbon steel and stainless steel hex bolts differ in mechanical properties, corrosion behaviour and applicable material grades. Carbon steel is commonly selected for general-purpose and structural fastening, while stainless steel may be chosen where corrosion resistance is needed. Buyers should confirm the specific material grade and corrosion expectations.
9. What is the difference between zinc-plated and hot-dip-galvanized hex bolts?
Zinc plating and hot-dip galvanizing are different coating systems with distinct coating thicknesses, thread fit implications and application environments. Zinc plating is commonly used for indoor exposure, while hot-dip galvanizing provides heavier coating for outdoor or structural use. Buyers should confirm the coating standard and thread fit after coating.
10. What information is required for a hex bolt RFQ?
A complete hex bolt RFQ should include standard, diameter, pitch or TPI, length, thread type, material, property class or grade, surface finish, quantity, packing and matching nut or washer requirements. Buyers should also indicate whether inspection documents or dimensional reports are required.
11. Can mixed sizes and grades be included in one RFQ?
Yes. Mixed-SKU RFQs can be reviewed when each size, grade, finish and packing requirement is listed on a separate line. Each standard and property class should be clearly separated. MOQ, pricing, packing and lead time are confirmed after manual RFQ review.
12. How can buyers source hex bolts from China?
Buyers can submit a drawing, BOM, or itemised RFQ with standards, dimensions, grades, finishes, quantities and packing requirements. Prices, MOQ, packing, documentation and lead time are confirmed after manual RFQ review.
Common Standards Reference
Use this table to organize RFQ language before confirming drawings, BOM notes, or project standards.
| Standard | Common Product Type | Thread Type | Typical Application | Buyer Note |
|---|---|---|---|---|
| DIN 933 | Metric hex bolt | Full thread | General machinery, construction, maintenance | Often compared with ISO 4017; confirm dimensions before substitution. |
| DIN 931 | Metric hex bolt | Partial thread | Assemblies needing a plain shank section | Plain shank length varies by size and length. |
| ISO 4017 | Metric hex bolt | Full thread | Newer ISO reference for full-thread hex bolts | Do not assume direct replacement without buyer approval. |
| ISO 4014 | Metric hex bolt | Partial thread | Newer ISO reference for partial-thread hex bolts | Confirm thread length, tolerance, and project acceptance. |
| ASME B18.2.1 | Inch hex cap screw / hex bolt reference | UNC or UNF | Inch-size industrial and machinery fastening | Specify diameter, threads per inch, length, and grade. |
| ASTM A307 | Carbon steel bolt | Project-dependent | General-purpose carbon steel fastening | Confirm grade, application, and inspection documents. |
| ASTM A325 | Structural heavy hex bolt | Project-dependent | Structural steel connections | Often handled through ASTM F3125 references; confirm project standard. |
| ASTM A490 | High-strength structural bolt | Project-dependent | High-strength structural steel connections | Confirm coating restrictions and project approval requirements. |
| DIN 6914 | High-strength structural hex bolt | Project-dependent | HV structural bolt assemblies | Usually reviewed with matching nuts and washers. |
Final specifications should be confirmed according to the buyer's drawing, BOM, project standard, or RFQ requirements.
Mechanical Properties and Materials
Grades and materials help buyers align strength expectations with application requirements.
| Grade | Common Materials | Typical Use | Buyer Confirmation Note |
|---|---|---|---|
| Metric Class 4.8 | Low-carbon steel | Low-load general fastening | Confirm if the application is non-critical and indoor. |
| Metric Class 5.8 | Low or medium-carbon steel | Moderate-duty assemblies | Confirm tensile requirement and inspection documents. |
| Metric Class 8.8 | Medium-carbon steel, quenched and tempered | General structural and machinery fastening | Often paired with Class 8 nuts; confirm finish and coating risk. |
| Metric Class 10.9 | Alloy steel, quenched and tempered | Higher-strength machinery and structural use | Check plating risk, baking requirements, and buyer approval. |
| Metric Class 12.9 | Alloy steel | Extreme-strength fastening where specified | Confirm engineering approval and hydrogen embrittlement controls. |
| Inch Grade 2 | Low or medium-carbon steel | General-purpose inch fasteners | Confirm ASTM or SAE reference and application load. |
| Inch Grade 5 | Medium-carbon steel, quenched and tempered | Automotive, machinery, industrial fastening | Confirm markings, test documents, and thread series. |
| Inch Grade 8 | Medium-carbon alloy steel, quenched and tempered | High-strength inch fasteners | Confirm finish, hardness, and matching nut grade. |
Final specifications should be confirmed according to the buyer's drawing, BOM, project standard, or RFQ requirements.
Surface Finish Directions
Surface treatment should be specified by application environment, corrosion expectation, thread fit, and document needs.
| Finish | Corrosion Resistance | Typical Use | RFQ Note |
|---|---|---|---|
| Zinc plated | Light to moderate | General indoor or light outdoor fastening | Specify clear, blue, yellow, or other finish if required. |
| Hot-dip galvanized | High | Outdoor construction and structural fastening | Confirm coating standard and thread fit after galvanizing. |
| Black oxide | Low | Indoor, tool, or appearance-driven applications | Not a substitute for corrosion-resistant coating. |
| Plain | Low | Dry indoor assembly or parts requiring later treatment | Clarify oiling, rust prevention, and packing protection. |
| Stainless steel | Material-dependent | Corrosion-resistant fastening where specified | Confirm A2/304, A4/316, or buyer material grade. |
| Zinc flake | Moderate to high | Automotive, machinery, or hydrogen-risk-sensitive applications | Confirm coating system, color, and salt spray requirement. |
| Phosphated | Low to moderate with oil | Pre-lubricated or friction-controlled assemblies | Confirm oiling, friction requirement, and storage condition. |
Final specifications should be confirmed according to the buyer's drawing, BOM, project standard, or RFQ requirements.
Hex Bolts RFQ Checklist
- Original buyer specification before conversion
- Standard
- Diameter
- Length
- Metric or inch unit system
- Thread pitch or TPI
- Thread type
- Grade / Class
- Material
- Surface finish
- Nut and washer pairing
- Quantity
- Packaging
- Application
- Inspection document requirement
- Destination country / port
- Special drawing or BOM
Common Procurement Mistakes
- Using a photo instead of a standard, drawing, or BOM.
- Mixing full-thread and partial-thread bolts in one SKU.
- Ignoring nut class, washer hardness, or coating compatibility.
- Assuming DIN and ISO references are always interchangeable.
- Requesting high-strength bolts without confirming finish and hydrogen embrittlement risk.
- Leaving packaging, carton weight, or pallet requirements unclear for mixed shipments.
Final specifications should be confirmed according to the buyer's drawing, BOM, project standard, or RFQ requirements.
Hex Bolts FAQ
Short answers for buyers preparing technical RFQs.
Can DIN 933 and ISO 4017 be substituted?
DIN 933 and ISO 4017 are both full-thread metric hex bolt references, but buyers should not treat them as automatically interchangeable. Dimensions, thread run-out, under-head details, and project acceptance should be confirmed before substitution.
How should buyers choose between Class 8.8 and Class 10.9?
Class 8.8 is often selected for general structural and machinery fastening. Class 10.9 may be selected where higher strength is required. Buyers should confirm load requirements, material, finish, coating risk, and engineering approval.
Do hex bolts need matching nuts and washers?
Many orders need matching nuts and washers. Confirm nut class, washer hardness, finish compatibility, thread fit, packing method, and whether the assembly should be supplied together.
Can buyers make a mixed hex bolt order?
Yes. Mixed hex bolt orders can be reviewed when each SKU has standard, size, grade, finish, quantity, packing, and inspection document requirements. Full-thread and partial-thread bolts should be separated.
How should surface treatment be specified in an RFQ?
Specify finish type, coating thickness or standard where required, color if relevant, application environment, corrosion expectation, and any coating report or salt spray requirement.
What affects the lead time for a mixed hex bolt order from China?
Lead time depends on standard, grade, finish, quantity, packaging, inspection documents, and shipping method. Final lead time is confirmed after RFQ review.
Can you review an RFQ that uses inch dimensions and convert it to metric references?
Yes. Reference conversions can be provided, but metric and inch products are not automatically interchangeable. The original thread system, pitch or TPI, dimensions, grade, matching components and applicable standard must remain part of the RFQ review.
What is a hex bolt?
A hex bolt is an externally threaded fastener with a hexagonal head, normally used with a nut or a tapped component. Buyers should specify the applicable standard, diameter, length, thread type, grade, material and finish per project requirements.
What is the difference between DIN 931 and DIN 933 hex bolts?
DIN 931 is a partially threaded metric hex bolt reference commonly used where a plain shank is required. DIN 933 is a fully threaded metric hex bolt reference. The choice depends on grip length, thread length, joint design and the applicable standard.
How do DIN 931 and ISO 4014 compare?
DIN 931 and ISO 4014 are commonly compared references for partially threaded metric hex bolts. Exact requirements including dimensions, tolerances and project acceptance must be confirmed before substitution.
What is the difference between fully threaded and partially threaded hex bolts?
A fully threaded hex bolt has threads extending along most of its shank, while a partially threaded bolt includes an unthreaded grip section. The choice depends on application requirements, joint design and the specified standard.
Can metric and inch hex bolts be substituted?
No. Metric and inch hex bolts are not automatically interchangeable. The thread system, diameter, pitch or TPI, length, head dimensions, grade and matching components differ between the two systems. Buyers should confirm the original specification. See the Metric and Inch Fastener Conversion Guide for reference.
What is the difference between carbon steel and stainless steel hex bolts?
Carbon steel and stainless steel hex bolts differ in mechanical properties, corrosion behaviour and applicable material grades. Carbon steel is commonly selected for general-purpose fastening, while stainless steel may be chosen where corrosion resistance is needed. Buyers should confirm the specific material grade.
What is the difference between zinc-plated and hot-dip-galvanized hex bolts?
Zinc plating and hot-dip galvanizing are different coating systems with distinct coating thicknesses and thread fit implications. Zinc plating is commonly used for indoor exposure, while hot-dip galvanizing provides heavier coating for outdoor or structural use.
What information is required for a hex bolt RFQ?
A complete hex bolt RFQ should include standard, diameter, pitch or TPI, length, thread type, material, property class or grade, surface finish, quantity, packing and matching nut or washer requirements.
How can buyers source hex bolts from China?
Buyers can submit a drawing, BOM, or itemised RFQ with standards, dimensions, grades, finishes, quantities and packing requirements. Prices, MOQ, packing, documentation and lead time are confirmed after manual RFQ review.
Final specifications should be confirmed according to the buyer's drawing, BOM, project standard, or RFQ requirements.
Related Links
Use these guides with the product page when preparing a buyer RFQ.
Send Hex Bolt RFQ for Manual Review
Send your product list, drawings, standards, quantities, finish requirements, and packing expectations to xyan060816@gmail.com.
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