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{"title":"DIN137B Wave Spring Washer 65Mn Spring Steel Mechanically Zinc Plated Curved","imgUrl":"https:\/\/img.chinax.com\/nimg\/0f\/5f\/8f6d28859dfca88753d593bd03a5-200x200-1\/din137b_wave_spring_washer_65mn_spring_steel_mechanically_zinc_plated_curved_disc_washer.jpg","attrs":{"Usage":"For Fastening Metal To Metal","Model Number":"washer","Connection":"Common Bolt","Place Of Origin":"ZHEJIANG CHINA"}}
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{"title":"Stainless Steel DIN137 Saddle Spring Washer SS304 A2 Type A Curved Lock Washer","imgUrl":"https:\/\/img.chinax.com\/nimg\/d4\/0a\/3ae8de2ea0cdcfb5a9348042446f-200x200-1\/stainless_steel_din137_saddle_spring_washer_ss304_a2_type_a_curved_lock_washer_for_anti_loosening.jpg","attrs":{"Usage":"For Fastening Metal To Metal","Model Number":"washer","Connection":"Common Bolt","Place Of Origin":"ZHEJIANG CHINA"}}
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GB21 Small Hexagon Head Bolts (Small Hex Head Bolts per GB 21-1976) are Chinese national standard fasteners featuring a compact hexagonal head design with smaller across-flats dimensions compared to standard GB30 hex bolts, making them ideal for tight spaces where standard bolts cannot fit.
Key Features
Compact Head Profile: Reduced hex head width allows installation in confined spaces without compromising clamping force
High Tensile Strength: Available up to Grade 12.9 with nominal tensile strength reaching 1,000 MPa after heat treatment
Versatile Material Grades: From Grade 4.8 for general-purpose fastening to Grade 10.9/12.9 for high-load structural connections
Multiple Surface Finishes: Zinc plating for indoor corrosion protection; hot-dip galvanizing and Dacromet for outdoor and harsh environments
Precision Manufacturing: Cold forging and CNC machining ensure dimensional accuracy and consistent thread quality per GB 21-1976 standards
Full Traceability: Mill test certificates and third-party inspection reports (SGS, BV) available upon request
Technical Specifications
Measurement System
INCH, Metric
Standard
DIN, ANSI, GB, JIS, BSW, GOST
Process
Cold Forging
Finish
Zinc Plated
Load Capacity
Medium Duty
Usage
For Fastening Metal To Metal
HS Code
7318151001
Customization Services
We offer comprehensive OEM and ODM services to meet your specific requirements:
Custom head styles, drive types (Phillips H / Pozidriv Z), and thread designs
Special lengths, diameters, and tolerances
Specific material grades and surface finishes
Custom packaging with your branding (labels, boxes, bags, blister packs)
Logo engraving on screw heads
Why Choose Us
Professional fastener manufacturer with over 10 years of export experience
Advanced automatic cold heading and thread rolling equipment ensuring consistent quality and fast delivery
Strict quality control system from raw material sourcing to finished product
Competitive factory-direct pricing with no middlemen
Responsive customer service and technical support
Flexible MOQ to accommodate both trial orders and bulk shipments
Product Images
Packaging Options
Bolts are packed in neutral packaging boxes with standard quantities arranged in small cartons. Custom packaging configurations are available upon request. Small cartons are consolidated into larger master cartons for secure transportation. Palletized units are wrapped with waterproof film and reinforced with packaging straps, with custom shipping marks available.
Ningbo Yongbiao Fastener Manufacturing Co., Ltd. is located in Ningbo, the second largest port city in China. The factory is 50 kilometers away from Ningbo Port and can reach the sea freight warehouse in one hour, with very fast logistics. The company was founded in 2012 and after years of hard work... Ningbo Yongbiao Fastener Manufacturing Co., Ltd. is located in Ningbo, the second largest port city in China. The factory is 50 kilometers away from Ningbo Port and can reach the sea freight warehouse in one hour, with very fast logistics. The company was founded in 2012 and after years of hard work...
