HEX BOLTS

The products are strictly conform with DIN, ISO, ASTM, ANSI, BS, JIS...

● Level: A325/A325M/A490/A490M/8.8 /10.9/12.9/Gr5/Gr8

● Coating: Plain/Black/Galvanized/H.D.G /YZP/Dacromet/Xylan

ASTM B7/B7M

THREAD RODS

The longest can reach 3.66 meters(12FT)

China Professional Metal Fasteners

Manufacturer and Supplier with Over 20 Years of Experience

Bolt

Head shape: Hexagonal head, square head, round head can all be produced.
Size: M4-M100, 3/8 "-4"...

Nut

Type: hex nut, cap nut, couple nut, lock nut, spring nut
Size: M4-M100, 3/8'-4' is divided...

Washer

Type: Flat washer, spring washer
Specifications: M3-M100, 1/4

Threaded Rod

Size: M4-M100, 3/8 "-4", divided into metric size and inch size
Thread type: Full Thread

Precast Accessories

Size: Customization based on drawings or samples, both metric size and inch size are available

Custom Fasteners

Size: Customization based on drawings or samples, both metric size and inch size are available

About Material

Carbon steel, alloy steel, stainless steel are all acceptable.
According to customer requirements

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Topbolt - Best Standard Bolts and Nuts for Your Industries

The products are applied to architectural steel structures, brigdes, oil, pipeline, machinery equipment, furniture, vessel, railway.

Bridge
Industry
Ship
Solar Power
Steel Structural

Why Choose Topbolt for Your Projects?

Trusted Supplier of Bolts, Nuts, and Fasteners Conforming to DIN, ANSI/IFI, JIS, BS, ISO, and GB Specifications.

Ningbo Topbolt Metalworks Co., Ltd. is a manufacturer in China which mainly produces high strength fasteners and specializes in all kinds of hardwares. Founded in 2001, In the past few years, it developed fast with its factory located in Ningbo Zhenhai Chemical industrial area and its headquarter /foreign sales department in Ningbo Jiangdong Eastern Business Centre.

The factory now covers an area of approximately 15,000 square meters, with monthly production capacity of 2000 tons. The company has its all-around research system, supply management, large-scale warehouse...

Founded In

㎡

Covers an Area

Monthly Production Capacity

million

Annual Sales

DIGITAL SHOWROOM

If you want to learn more about our manufacturing capabilities, you can click on the avatar in the scene, or accept my invitation!

What Makes Topbolt Fasteners Manufacturing Stand Out?

Material Science

Carbon steel, alloy steel, stainless steel, Special material customization
Direct procurement from raw material factories, discounted prices, and sufficient stock availability

Standard

Strictly produce according to standard dimensions such as DIN, ISO, GB, JIS, ASTM, SAE, ASME, etc

Services

Accept customized production (including sample processing, drawing processing), OEM production

Topbolt News & Fasteners Knowledge Center

ISO 4014 Hex Head Bolt Partial Thread.png

Pickling vs Passivation for Stainless Fasteners: Why Pickling Alone Causes Rust

2026-11-13

When buying stainless steel fasteners overseas, many customers confuse pickling with passivation. They request passivation but receive parts that were only pickled, then see rust spots and pitting shortly after installation. Pickling removes mill scale and heat tint; it does not improve corrosion resistance. Passivation removes free iron and builds a chromium-rich protective film that genuinely improves rust performance. This article compares the two processes on surface condition, salt spray performance and applications, helping buyers specify and inspect the correct treatment and avoid suppliers swapping processes.

2026-11-13

Flat Washer Selection Mistakes: Thin & Non-Standard Washers Crushed Under Load

2026-11-12

Many buyers and fitters only check inner and outer diameter when selecting flat washers, ignoring washer hardness and effective bearing area. Using soft plain washers with high-strength bolts will cause washer crushing and loss of preload after tightening, leading to loose connections and hidden safety risks. This article focuses on 【DIN125 flat washer】, introduces material and hardness matching rules for different bolt grades, key selection parameters, failure modes and checking methods, helping you avoid rework and order rejection.

2026-11-12

ASTM A325 Bolts: Installation Requirements for Friction-Type Steel Connections

2026-11-11

For steel structure projects in North America, slip-critical friction joints have strict requirements for **A325 bolts**. Many overseas buyers mistakenly replace them with metric Grade 8.8 bolts because of similar mechanical strength, resulting in failed pull-out inspection and rejection by site inspectors. A friction joint transfers load by friction between steel plates instead of bolt shear. Faying surface preparation, preload torque control, matched nut & washer sets and bolting sequence directly determine slip safety. This article follows RCSC and AISC codes, covers installation rules, substitution risks and inspection standards for **A325 bolts**, to help buyers and installers avoid rework and order rejection.

2026-11-11

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We welcome all of you from all over the world to join us for the win-win business partnership and friendship, welcome to China, welcome to Ningbo Topbolt!

China Professional Metal Fasteners

Topbolt - Best Standard Bolts and Nuts for Your Industries

Why Choose Topbolt for Your Projects?

DIGITAL SHOWROOM

Pickling vs Passivation for Stainless Fasteners: Why Pickling Alone Causes Rust

Flat Washer Selection Mistakes: Thin & Non-Standard Washers Crushed Under Load

ASTM A325 Bolts: Installation Requirements for Friction-Type Steel Connections

Get A Free Quate

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