Silicon Bronze Fasteners | Full Factory Production Process

Our factory specializes in the in-house R&D and mass production of silicon bronze fasteners. Our core product range includes silicon bronze hex bolts, countersunk bolts, hex nuts, flat washers, and spring washers. Utilizing a full suite of automated production equipment, we manage the entire manufacturing process—from raw material intake (silicon bronze rods/wire) through cold heading, thread rolling, and final inspection—within our own workshops. We strictly control the material composition, dimensions, and thread precision of every finished part, supplying both standard and custom-engineered fasteners for sectors such as marine engineering, chemical processing equipment, power infrastructure, and anti-corrosion projects.

Silicon bronze alloys offer excellent resistance to seawater corrosion and galling, are non-sparking, and possess good electrical conductivity, making them ideal for long-term use in highly corrosive environments. However, due to the alloy's high toughness, it is more difficult to process than standard brass and places higher demands on tooling and production techniques. We have optimized our specialized molds and equipment parameters to suit the specific characteristics of silicon bronze, ensuring consistent quality across high-volume production runs.

Daily machine production processes in the workshop

Raw Material Screening and Preparation

Upon receipt, silicon bronze wire and rod materials undergo verification of material properties and alloy composition. Corresponding blanks are cut according to order specifications, and surface oxide layers are removed to prepare for subsequent forming operations.

Cold heading and forming

Hex bolt blanks are produced using multi-station cold heading machines. At room temperature, high-pressure extrusion via dies allows for the simultaneous forming of the bolt head and shank; this process preserves the continuity of the metal grain flow, thereby imparting superior overall strength to the part. The hexagonal head is shaped through a trimming process, followed by thread rolling.

Hex nuts, flat washers, and spring washers are manufactured using specialized cold heading and stamping equipment, with independent production scheduling to prevent the mixing of different products.

Thread rolling silicon bronze bolts

The formed bolt blanks are fed into a thread-rolling machine—a core step in the production of silicon bronze hex bolts.

External threads are formed through cold rolling between two high-precision thread-rolling dies, rather than by cutting or machining. This process preserves the continuity of the metal grain structure, resulting in fully formed thread profiles and smooth surfaces; the resulting threads offer superior tensile and fatigue strength while reducing the risk of galling or stripping during use.

Given the high toughness of silicon bronze, the workshop carefully calibrates the machine's pressure and feed rate and utilizes specialized dies designed for the material. These measures prevent issues such as thread tearing, burrs, and chipped teeth, ensuring that both metric and imperial threads meet all specifications.

The internal threads of the nuts are produced using tapping equipment, while flat washers and spring washers undergo elasticity testing after stamping to ensure their resilience meets the required standards.

Full-dimensional quality inspection

Upon completion of each production batch, sampling inspections are conducted, including thread go/no-go gauge testing, measurement of outer diameter and thickness, and visual inspections to check for burrs, dents, or cracks. For critical orders, a spectral material analysis report can be provided to verify the silicon bronze alloy composition. Non-conforming parts are immediately rejected and excluded from the packaging stage.

Sorting, Separate Packaging, and Boxing

Silicon bronze hex bolts, hex nuts, flat washers, and spring washers that have passed inspection are sorted by specification and packed in set quantities into transparent PE bags, each labeled with its specifications and material. These are then neatly arranged into reinforced export-grade corrugated cardboard boxes for shipment; orders ranging from small sample requests to large-volume full-container loads are all accepted.

We can supply

• Silicon Bronze Hex Bolts: Available in various metric and imperial specifications; external threads formed via thread rolling.

• Silicon bronze hex nuts, matching corresponding thread specifications.

• Silicon bronze flat washers, spring washers, and matching bolt and nut sets.

• Customization of non-standard sizes is supported; development and production can be carried out based on drawings or samples.