Learn more about ANSI/ASME/ASTM Standard Fasteners with us | Automotive Fastener Manufacturer-Zhejiang Zhongrui Auto Parts Co., Ltd.

At Zhejiang Zhongrui Auto Parts, we understand that fasteners are the backbone of mechanical and engineering systems, playing a critical role in ensuring the reliability and performance of countless applications, especially within the automotive industry. We specialize in manufacturing fasteners according to precise specifications, with a strong focus on American standards such as ANSI, ASME, and ASTM.

Navigating the world of fasteners defined by American standards and their associated specifications is essential for identifying and selecting the right components for your projects, particularly for designs intended for the North American market or global platforms adopting these norms. Knowing these standards helps ensure your fasteners are reliable, efficient, and compatible with intended uses in demanding engineering and automotive applications.

Here is an overview of some of the ANSI, ASME, and ASTM fastener standards and product types we are familiar with and supply, highlighting their relevance for EV and engineering machinery applications:

ASME B18.2.1 – Square and Hex Bolts and Screws:
This standard covers dimensional requirements for various bolts and screws with external wrenching heads. Hex bolts are workhorses for general fastening, while square bolts are used in specific legacy or anti-rotation applications. They are fundamental in securing structural components in engineering machinery and vehicle chassis.

ASME B18.2.2 – Square and Hex Nuts:
This standard defines dimensional requirements for various nuts. Hex nuts are the most common type, paired with bolts for clamping. Square nuts are used in channels or specific assemblies where anti-rotation is needed in the nut. Essential for creating secure bolted joints in all engineering systems.

ASME B18.3 – Socket Cap, Shoulder, and Set Screws:
This standard covers screws with internal wrenching drives (like Hex Socket or Torx). Socket head cap screws are used in tight spaces or for a clean finish, offering high clamping force. Set screws are used for positioning or locking components on shafts. Relevant in compact EV powertrains and complex machinery assemblies.

ASME B18.5 – Round Head Bolts:
This standard includes bolts like carriage bolts, which feature a smooth round head and a square neck to prevent rotation during installation. Commonly used in securing wooden components or where a square recess is available for anti-rotation in vehicle interiors or machinery.

ASME B18.8.2 – Pins (Dowel Pins, Clevis Pins, Cotter Pins, etc.):
This standard covers various pin types used for alignment, pivoting, and locking. Dowel pins provide precise component alignment in engines and transmissions. Clevis pins are used in linkages and hinges. Cotter pins are essential for securing castle nuts or clevis pins. All are vital in automotive and machinery assemblies.

ASME B18.22.1 – Washers (Flat, Lock, Spring, etc.):
This standard covers various washer types. Flat washers are fundamental for load distribution and surface protection. Lock washers provide tension or locking features to resist loosening. Essential under bolt heads and nuts in nearly all mechanical joints.

ASTM A307 – Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength:
A common specification for low-strength carbon steel bolts and studs used for general purpose applications in machinery and non-safety-critical automotive components.

ASTM A325 / ASTM A490 – Structural Bolts:
These are key specifications for high strength heavy hex structural bolts. A325 is for connections with tensile strength up to 120/105 ksi, while A490 is for even higher strength connections up to 150 ksi. Critical in joining structural steel components in heavy-duty vehicle frames and engineering machinery.

ASTM F436 – Hardened Steel Washers:
This specification covers hardened washers intended for use with structural bolts (like A325 and A490) and other fasteners. They prevent galling and embedment, ensuring proper load distribution in high-strength bolted joints.

ASTM B117 – Salt Spray Testing:
This is not a fastener standard but a crucial testing standard often referenced in fastener specifications. It defines the procedure for salt spray (fog) testing, used to evaluate the corrosion resistance of fasteners and their coatings. Essential for verifying performance in automotive environments exposed to salt and moisture.

ASTM B633 – Electrodeposited Coatings of Zinc on Iron and Steel:
A key standard for zinc plating, a common surface treatment for steel fasteners to provide corrosion protection. Often referenced in fastener standards like ASTM A307.

ASTM F593 / ASTM F594 – Stainless Steel Bolts, Hex Cap Screws, and Nuts:
These specifications cover stainless steel bolts and nuts for general use, offering corrosion resistance. Available in various alloys and strength levels suitable for automotive and machinery applications exposed to corrosive environments.

ASTM F835 / ASTM F837 / ASTM F879 / ASTM F912 – Various Stainless Steel Socket Products:
These cover stainless steel socket head cap screws, shoulder screws, set screws, etc., providing corrosion resistance combined with internal wrenching capability. Relevant in corrosive automotive or machinery environments where space is limited.

ASTM F3125 – High Strength Structural Bolts:
This is a modern combined standard that consolidates and supersedes A325, A490, and other related specifications for high-strength structural bolts and assemblies. Represents the latest standards for critical structural fastening.

This overview provides a glimpse into the world of fasteners governed by American standards. At Zhejiang Zhongrui Auto Parts, we are equipped to manufacture and supply a wide range of fasteners meeting these ANSI, ASME, and ASTM specifications. Our commitment to quality and precision ensures that whether you require a standard US component or a custom solution based on these principles, you receive reliable and efficient fasteners for your engineering and automotive projects.

Meet a few members of our dedicated team, ready to help you:
Coco Chen, Director of Business Development: coco.chen@zjzrap.com
Freddie Xiao, Account Manager: freddie.xiao@zjzrap.com
Brian Xu, Technical Sales Assistant: brian.xu@zjzrap.com

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