Flange Bolt

DIN6921 Carbon Steel Hex Head Flange Screw

DIN6921 Carbon Steel Hex Head Flange Screw, our bolts offer exceptional performance and reliability in even the most demanding environments. The hexagon flange design of these bolts provides a larger bearing surface and a more secure fastening, ensuring that your equipment remains safe and secured at all times. Additionally, our bolts are designed with a metric thread which is perfect for use in a wide range of industrial and engineering applications.pplications.

DIN6921 Carbon Steel Hex Head Flange Screw, our bolts offer exceptional performance and reliability in even the most demanding environments. The hexagon flange design of these bolts provides a larger bearing surface and a more secure fastening, ensuring that your equipment remains safe and secured at all times. Additionally, our bolts are designed with a metric thread which is perfect for use in a wide range of industrial and engineering applications.pplications.

Product Details

Product Introduction
Carbon steel hex head flange screws manufactured to DIN 6921 without serration under the bearing face. The integrated circular flange increases the load-bearing contact area and functions as a captive washer, eliminating the need for a separate flat washer in most assemblies. Sizes in M5 through M20 are available, higher diameters upon request, across property classes 8.8, 10.9, and 12.9 per ISO 898-1. Surface finishes are selected to meet the target service environment.

Material & Mechanical Properties
Fabricated from medium carbon steel; quenched and tempered where the property class requires. Heat-number traceability is maintained, with certified tensile, proof load, and hardness values issued on mill test reports. The carbon steel substrate provides the strength and toughness necessary for bolted joints subject to static, cyclic, and impact loads. Classes 8.8 and 10.9 satisfy general and high-strength engineering applications; class 12.9 is specified when tensile strength above 1200 MPa is demanded.

Geometry & Thread
Hexagonal drive head per standard wrench size. The bottom flange face is smooth and non-serrated, making it appropriate for assemblies where surface scoring or indentation must be avoided—such as painted, powder-coated, or plated mating parts. Coarse metric thread to ISO 724 facilitates rapid threading and maintains stripping resistance in common structural and mechanical materials. Shank length is partially threaded as default; fully threaded options are available.

Corrosion Protection
Electroplated zinc to ASTM B633 (Fe/Zn 5–8 µm) with clear passivation as standard, providing reliable indoor and sheltered outdoor corrosion resistance. For higher corrosivity categories (C3–C5), zinc flake, zinc-nickel alloy, or hot-dip galvanized coatings are applied. Coating systems are controlled to remain below the hydrogen embrittlement risk zone for each property class.

Application Suitability
Automotive engine and drivetrain assemblies, pump and compressor housings, structural steel frames, agricultural equipment, and industrial machinery where a one-piece flanged fastener replaces a bolt-and-washer set. The non-serrated flange suits joints where surface preservation, uniform clamp distribution, and simple inventory management are priorities.

 

Technical Parameters

Place of Origin CHINA
Standard DIN6921 Carbon Steel Hex Head Flange Screw
HS CODE 7318159001
Brand Name QBH
Certification ISO9001
Material 35K, 40Cr, 35CrMo, SCM435，etc.
Size M3-M64
Production Process Cold forging≤300mm,Hot forging≤1000mm
Class 4.8/ 6.8/ 8.8/ 10.9/ 12.9
Delivery Time Within 30Days

Product Introduction
Carbon steel hex head flange screws manufactured to DIN 6921 without serration under the bearing face. The integrated circular flange increases the load-bearing contact area and functions as a captive washer, eliminating the need for a separate flat washer in most assemblies. Sizes in M5 through M20 are available, higher diameters upon request, across property classes 8.8, 10.9, and 12.9 per ISO 898-1. Surface finishes are selected to meet the target service environment.

Material & Mechanical Properties
Fabricated from medium carbon steel; quenched and tempered where the property class requires. Heat-number traceability is maintained, with certified tensile, proof load, and hardness values issued on mill test reports. The carbon steel substrate provides the strength and toughness necessary for bolted joints subject to static, cyclic, and impact loads. Classes 8.8 and 10.9 satisfy general and high-strength engineering applications; class 12.9 is specified when tensile strength above 1200 MPa is demanded.

Geometry & Thread
Hexagonal drive head per standard wrench size. The bottom flange face is smooth and non-serrated, making it appropriate for assemblies where surface scoring or indentation must be avoided—such as painted, powder-coated, or plated mating parts. Coarse metric thread to ISO 724 facilitates rapid threading and maintains stripping resistance in common structural and mechanical materials. Shank length is partially threaded as default; fully threaded options are available.

Corrosion Protection
Electroplated zinc to ASTM B633 (Fe/Zn 5–8 µm) with clear passivation as standard, providing reliable indoor and sheltered outdoor corrosion resistance. For higher corrosivity categories (C3–C5), zinc flake, zinc-nickel alloy, or hot-dip galvanized coatings are applied. Coating systems are controlled to remain below the hydrogen embrittlement risk zone for each property class.

Application Suitability
Automotive engine and drivetrain assemblies, pump and compressor housings, structural steel frames, agricultural equipment, and industrial machinery where a one-piece flanged fastener replaces a bolt-and-washer set. The non-serrated flange suits joints where surface preservation, uniform clamp distribution, and simple inventory management are priorities.

 

Technical Parameters

Place of Origin CHINA
Standard DIN6921 Carbon Steel Hex Head Flange Screw
HS CODE 7318159001
Brand Name QBH
Certification ISO9001
Material 35K, 40Cr, 35CrMo, SCM435，etc.
Size M3-M64
Production Process Cold forging≤300mm,Hot forging≤1000mm
Class 4.8/ 6.8/ 8.8/ 10.9/ 12.9
Delivery Time Within 30Days
FAQ

1. How do you let me trust you.

Jiaxing City Qunbang Hardware Co.,ltd hs its own right of import and export,QBH trademark in China,United States,European Union have been registered.At the same time,you can also check the registration information of our company in the China industry and Commerce system.

 

2. How about your price.

We will be based on different markets,for different quality and quantity,tailor-made prices for customers,in order to achieve win-win goal.

 

3. How do you control your quality.

Incoming quality contral( IQC)→Process Quality control(PQC)→Output quality control(OQC),and the random samples is sent to TUV for testing.If the customer received the goods and found quality problems,QBH company promises to be responsible for returning money or replenishing the goods

 

4. Could you provide free samples?

For new customer, We can provide free samples for standard fastener, But the clients will pay the express

charges. For old customer, We will send you free samples and pay express charges by ourself.

 

5. What is your packing.

Usually 25KG/carbon,36CTNS on the pallets,or 20-30kg/Bags,then on the pallet,QBH company personalized packagingis also available,like 10PCS/plastic bag or 10pcs/box,it can print some information

such as LOGO and pattern of customers.

 

6. What is your payment term

Normally,our terms of payment are TT and L/C,if we cooperate for a long time,we can reach the point of mutual trust,and fully support our customers to become bigger and stronger in the local market.Not only in the price concessions,but also in the payment can also be made on credit,Specific credit sales time needs to be negotiated separately.

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