Hexagonal Outside Scarfing Insert for ERW Tube Mill

What Is a Hexagonal Outside Scarfing Insert?

A Hexagonal Outside Scarfing Insert is a replaceable tungsten carbide cutting insert designed to remove the external weld bead (outside burr) immediately after high-frequency welding in an ERW tube mill. It is one of the most important consumable tools for producing smooth and high-quality welded steel pipes.

Unlike solid cutting tools, the insert is mounted onto an Outside Scarfing Tool Holder (Knife Bar) with a clamping screw. When one cutting edge becomes worn, the insert can simply be indexed to a new edge, greatly reducing tooling cost and machine downtime.

• ✅Replaceable tungsten carbide insert

• ✅Six usable cutting edges for longer service life

• ✅High wear resistance and heat resistance

• ✅Designed for continuous online ERW tube production

• ✅Compatible with various outside scarfing tool holders

The Insert Must Be Used with a Tool Holder

The insert alone cannot perform cutting. It always works together with the Outside Scarfing Tool Holder, which fixes the insert at the correct cutting angle and applies stable cutting pressure during production.

The holder provides rigidity, while the carbide insert performs the actual machining. Replacing only the insert instead of the complete holder makes maintenance faster and more economical.

Working Principle

The hexagonal outside scarfing insert removes the external weld bead immediately after high-frequency welding. Mounted on the outside scarfing tool holder, it continuously cuts the raised weld bead while the tube is moving, ensuring a smooth surface before entering the sizing section.

Production Process→ HF Welding External→ Weld Bead Formed→ Hexagonal Outside Scarfing Insert→ Removes the Bead Smooth Tube→ Surface Sizing Section

Process Description

• HF Welding: The strip edges are joined by high-frequency welding.

• External Weld Bead: A raised outside weld bead is created along the weld seam.

• Scarfing: The hexagonal carbide insert precisely removes only the excess weld bead without damaging the pipe body.

• Surface Finish: The pipe obtains a clean and uniform outside surface.

• Sizing: The tube enters the sizing section for final diameter and shape control.

Common Types of Outside Scarfing Inserts

Different tube mills use different insert geometries. The most common types include four-sided, six-sided, and eight-sided inserts.

Selection depends on the tool holder design, tube diameter, material, production speed, and required surface quality rather than simply choosing the insert with the most edges.

Typical Technical Specifications

The cutting radius is matched to the tube outside diameter. Different radius models are available for different production ranges.

How to Select the Correct Insert

Choosing the correct insert requires matching several production parameters:

1. Tube outside diameter – determines the insert radius.

2. Wall thickness – influences cutting load.

3. Steel material – HR, CR, galvanized, or stainless steel.

4. Production speed – higher speeds require better wear resistance.

5. Tool holder model – insert geometry must match the holder.

Providing the tube size and holder drawing allows accurate insert selection and ensures stable burr removal.

FAQ

Is the hexagonal insert supplied with the tool holder?

It can be supplied separately or together with the matching Outside Scarfing Tool Holder, depending on your requirement.

The insert has six usable cutting edges. When one edge becomes worn, it can be rotated to the next edge.

Can it be customized?

Yes. The insert radius, coating, and dimensions can be customized according to your tube diameter, holder drawing, or sample.

Is it suitable for galvanized steel tubes?

Yes. With the appropriate carbide grade and coating, it performs well on carbon steel, cold rolled, and galvanized ERW tubes.