Why Internal Burrs Appear After Tube Cutting

If you've ever had to reject an entire batch of steel tubes because of internal burrs after cutting, you're not alone. At first glance, a cut may seem decent from the outside. But peek inside — and you may find jagged metal flakes, curled debris, and sharp protrusions that can damage tools, cause welding defects, or injure workers.

In the photo above, we see tubes have severe internal burring and thermal deformation.

Let’s dig into why this happens — and how to fix it in real production environments.

What Causes Internal Burrs in Tube Cutting?

1. Worn or Inappropriate Cutting Disc

Most internal burrs result from discs that tear rather than slice through the material. Dull edges or incorrect bonding will cause material shearing inward, curling burrs into the inside.

Recommendation: For cutting structural steel tubing, use T.C.T. blades with ATB (Alternate Top Bevel) geometry or reinforced abrasive discs designed for metal tubing. Avoid universal blades meant for both metal and wood.

2. Excessive Feed Pressure

If the operator applies too much pressure or too high RPM, the disc may deform or “push” molten debris into the inner cavity. This leads to slagging, burr curling, and edge flaking inside the tube.

Recommendation: Slow down the feed rate and allow the blade to perform a clean shearing action. Use automatic feed controls or instruct manual operators to avoid forcing the blade through.

3. Poor Blade Alignment or Runout

Even slight off-axis vibration or disc misalignment causes uneven contact during cutting, which results in material peeling inward. The blade grabs and folds metal rather than cutting flush through the wall.

Recommendation: Inspect arbor tolerances and ensure all blades run with minimal lateral runout (<0.15mm). Always re-balance machines after changing discs.

4. Inadequate Workholding or Clamping

If the tubing shifts during cutting, the blade’s exit point becomes unstable, causing chipout and internal tear-out near the end.

Recommendation: Use precision vises or custom clamps that stabilize all three axes of the tube — especially for thin-wall rectangular profiles.

 Solutions Summary Table

Real Case: A Furniture Tube Factory in Turkey

One of our OEM clients producing metal bed frames switched from low-cost abrasive discs to 40T ATB TCT blades. After one month:

• Internal burr rate dropped from 22% to under 4%

• Rework costs were cut by 60%

• Welders reported faster fitting and smoother seams
  Sometimes, the solution is not upgrading the machine — it’s specifying the right blade.

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 Final Advice for Importers & Procurement Officers

If you're sourcing cutting discs or specifying tooling for factories, ask for burr test results, not just material specs. A disc that cuts quickly but leaves internal mess is not production-friendly — it’s just shifting the problem downstream.