Hot forging die for hexagonal bolts Manufacturing method

Hot forging of hexagonal bolts involves shaping metal at elevated temperatures to produce the desired geometry. Here’s a basic outline of the manufacturing process for hot-forged hexagonal bolts:

1. Material Selection:

Material: The most common materials used for hexagonal bolts are carbon steel, alloy steel, stainless steel, or other specialized alloys depending on the intended application (e.g., high strength, corrosion resistance).

Billet: A cylindrical piece of metal (usually in the form of a billet or bar stock) is chosen as the starting material. The size of the billet is chosen based on the desired dimensions of the bolt.

2. Heating:

Pre-heating: The billet is heated in a furnace to a temperature suitable for forging, typically between 1,100°C to 1,300°C (2,012°F to 2,372°F) depending on the material.

The temperature must be high enough to soften the metal, allowing it to be deformed easily without cracking.

3. Forging Process:

Die Setup: The forging dies are prepared for hexagonal bolt formation. These dies are often custom-made to the exact specifications of the bolt size, head shape, and other features (e.g., threads).

Initial Forging: The heated billet is placed into the lower die cavity. A ram (or hammer) is then used to apply force to the billet, pressing it into the shape of the bolt.

The forging die may have a hexagonal die cavity to create the head shape.

Upsetting: In some cases, the portion of the bolt that forms the head is “upset” or compressed to make it thicker.

Extrusion/Swaging: Some bolts may undergo additional shaping through extrusion or swaging processes to form the shank or threads.

4. Shaping the Hexagonal Head:

After the billet is formed into a cylindrical or round shape, it is pressed into a hexagonal die. The die ensures the bolt head takes the characteristic hexagonal shape.

At this stage, excess material may be trimmed off, and the head is flattened to the desired thickness.

5. Cooling and Normalizing:

Cooling: The forged bolt is then cooled in air or water to harden it. The cooling rate can affect the material properties, so it must be controlled to prevent warping or cracking.

Normalizing (Optional): Some bolts may undergo normalizing, where they are heated to a specific temperature and then cooled slowly to refine the grain structure and enhance strength.

6. Thread Formation:

After the forging process, threads may be formed on the shank of the bolt using one of the following methods:

Thread Rolling: A cold or warm process in which the shank is passed through a set of dies to roll threads onto it.

Cutting or Tapping: For some designs, threads are cut or tapped after forging, especially when high precision is required.

7. Trimming and Finishing:

After forging and cooling, any extra material (such as flash or burrs) is trimmed off using machines like trimming presses or grinders.

The surface of the bolt may also be smoothed out, and additional finishing treatments (e.g., heat treatment, coating) are applied if required for corrosion resistance or enhanced strength.

8. Quality Inspection:

Dimensional Checks: The finished hexagonal bolt is inspected for proper dimensions, including head size, shank length, thread alignment, and hexagonal shape.

Material Testing: The bolt is often subjected to mechanical testing, such as tensile strength tests, hardness tests, and microstructure analysis.

9. Coating (Optional):

Surface Treatment: Some bolts are coated with a protective layer (e.g., zinc plating, black oxide coating) to improve corrosion resistance or aesthetics.

10. Packaging and Shipment:

The finished hexagonal bolts are then packed in bulk or in smaller quantities, depending on the customer requirements, and shipped out for distribution.

This process ensures that the hexagonal bolts are strong, durable, and accurately shaped to meet engineering standards for their intended application.

As a professional manufacturer and supplier, we provide high-quality products. If you are interested in our products or have any questions, please feel free to contact us.