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Wholesale Large Flat Round Head Square Neck Carriage Bolt (Long/Partial Thread) Suppliers
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Carriage Bolt

Large Flat Round Head Square Neck Carriage Bolt (Long/Partial Thread)

Product Overview
The Large Flat Round Head Square Neck Carriage Bolt  (Long/Partial Thread) is built for deep assemblies requiring partial thread engagement, featuring a long, smooth shank with controlled threading for enhanced structural flexibility.


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Large Flat Round Head Square Neck Carriage Bolt (Long/Partial Thread)
Large Flat Round Head Square Neck Carriage Bolt (Long/Partial Thread)
Attributes
Zhejiang Chance & Union Import and Export Co., Ltd.

Key Features
Long overall length designed for thick material stacks and deep structural connections.
Half-thread design leaves a smooth, unthreaded shank for improved alignment and shear strength.
Large flat head provides a broad bearing surface for heavy clamping loads.
Square neck prevents rotation during nut tightening, even in long-reach applications.
Available in corrosion-resistant materials for outdoor and harsh-environment use.

Product Features
Zhejiang Chance & Union Import and Export Co., Ltd.
SAE Grade 5.8 (Equivalent to ISO 5.8)
Bolt Diameter M5–M20 (Customizable)
Thread Type UNC / UNF (Customizable; ISO metric thread for metric options)
Standards DIN 603 / SAE J429 / ASTM A307 (Switchable per customer requirements)
Strength Grade SAE Grade 5.8
Heat Treatment Quenched & Tempered (Q&T)
Tensile Strength ≥500?MPa
Yield Strength ≥400?MPa
Hardness HRC 22–27
Head Style Mushroom head with square neck, Phillips recess
Thread Accuracy / Tolerance 2A / 3A (Inch); 6g (Metric)
Operating Temperature -40°C to 250°C
Matching Components Hex nuts (DIN 934), Flat washers (DIN 125)

SAE Grade 8.8 (Equivalent to ISO 8.8)
Bolt Diameter M5–M20 (Customizable)
Thread Type UNC / UNF (Customizable)
Standards DIN 603 / SAE J429 / ASTM A325
Strength Grade SAE Grade 8.8
Material Medium carbon steel (C45 / SAE 1045)
Heat Treatment Quenched & Tempered (Q&T)
Tensile Strength ≥800?MPa
Yield Strength ≥640?MPa
Hardness HRC 24–33
Head Style Mushroom head with square neck, Phillips recess
Thread Accuracy / Tolerance 2A / 3A
Operating Temperature -40°C to 300°C
Matching Components Hex nuts (DIN 934), Flat washers (DIN 125), Spring washers (DIN 127)

SAE Grade 10.9 (Equivalent to ISO 10.9)
Bolt Diameter M5–M20 (Customizable)
Thread Type UNC / UNF (Customizable)
Standards DIN 603 / SAE J429 / ASTM A490
Strength Grade SAE Grade 10.9
Material Alloy structural steel (40Cr / SAE 4140)
Heat Treatment Quenched & Tempered (Q&T)
Tensile Strength ≥1000?MPa
Yield Strength ≥900?MPa
Hardness HRC 32–39
Head Style Mushroom head with square neck, Phillips recess
Thread Accuracy / Tolerance 2A / 3A
Operating Temperature -40°C to 350°C
Matching Components High-strength hex nuts (DIN 934, Class 10), Flat washers (DIN 125)

SAE Grade 12.9 (Equivalent to ISO 12.9)
Bolt Diameter M5–M20 (Customizable)
Thread Type UNC / UNF (Customizable)
Standards DIN 603 / SAE J429 / ASTM A490
Strength Grade SAE Grade 12.9
Material Alloy structural steel (35CrMo / SAE 4135)
Heat Treatment Quenched & Tempered (Q&T)
Tensile Strength ≥1200?MPa
Yield Strength ≥1080?MPa
Hardness HRC 39–44
Head Style Mushroom head with square neck, Phillips recess
Thread Accuracy / Tolerance 2A / 3A
Operating Temperature -40°C to 380°C
Matching Components High-strength hex nuts (DIN 934, Class 12), Flat washers (DIN 125)
Applications
Zhejiang Chance & Union Import and Export Co., Ltd.

Applications
Timber framing, deck construction, heavy-duty wood-metal assemblies, structural beams, and outdoor landscape projects requiring long-reach fasteners.

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Zhejiang Chance & Union Import and Export Co., Ltd.
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Zhejiang Chance & Union Import and Export Co., Ltd.
Zhejiang Chance & Union Import and Export Co., Ltd.
About Us
Fastening Chances,
Strengthening Union
Specializes in high-strength fasteners. As China wholesale Large Flat Round Head Square Neck Carriage Bolt (Long/Partial Thread) suppliers and Large Flat Round Head Square Neck Carriage Bolt (Long/Partial Thread) company, we offer Large Flat Round Head Square Neck Carriage Bolt (Long/Partial Thread), bolts, nuts, washers, and custom parts made from stainless steel, alloy steel, and more, serving over 200 clients in 25 countries. With 20 years of industry experience, we provide tailored fastening solutions from R&D to mass production.
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Zhejiang Chance & Union Import and Export Co., Ltd.
Certifications & Honors
Zhejiang Chance & Union Import and Export Co., Ltd.
Utility Model Patent Certificate
Utility Model Patent Certificate
Utility Model Patent Certificate
Utility Model Patent Certificate
Utility Model Patent Certificate
Utility Model Patent Certificate
Utility Model Patent Certificate
Utility Model Patent Certificate
Utility Model Patent Certificate
Utility Model Patent Certificate