Beam Bevel Cutting: V, Y and K Weld Bevels on H-Beams
A 5-axis laser cuts weld bevels on H-beam flanges and webs at any angle up to ±45°, in V, Y or K form, in the same program as the cope, weld access hole and bolt holes. The bevel comes off the machine ready to fit up, so there is no flame cutting and grinding at a separate station.
At a glance
- Bevel angle 0–45° either side, set per edge in the program.
- V, Y (with root face) and K (double-sided) bevels on flanges and webs.
- 5-axis TCP head: A axis 360°, C axis 180°, holds the angle around the section.
- Bevel, cope, access hole and holes cut in one setup on beams up to 1,000 mm.
- At 45° the beam passes through about 1.41× the plate thickness.
On this page
V, Y and K bevels
| Bevel | Shape | Typical use |
|---|---|---|
| V (single bevel) | One angled cut through the full thickness | Thin and medium flanges, groove welds with backing bar |
| Y (bevel with land) | Angled cut plus a straight root face at the bottom | Open-root welds where the land controls burn-through |
| K (double bevel) | Beveled from both faces, land in the middle | Thick flanges, where it roughly halves the weld metal |
The bevel angle, land height and side are taken from the joint detail on the drawing or from the DSTV file, edge by edge. Always follow the welding procedure specification for the project; the machine simply cuts what the detail calls for.
Where bevels go on a beam
- Flange ends in moment connections. Beam flanges welded to a column with complete joint penetration welds need a bevel on each flange, usually together with a weld access hole in the web. See weld access holes and beam coping.
- Web ends for full-strength web splices and built-up girders.
- Cope edges where a coped beam is welded rather than bolted.
- Mitered ends on frames and portal knees, where the miter and the bevel are one cut.
- Channels and angles in welded frames, using the same program logic. See channel, angle and I-beam laser cutting.
How the 5-axis head cuts a bevel
- Measure. The machine finds the real position of the flange and web, since rolled sections are never perfectly straight or square.
- Tilt. The head tilts to the bevel angle. The A axis turns 360° and the C axis 180°, so the head can reach both flange faces and the web.
- Hold the tool centre point. TCP control keeps the focus on the cutting line while the head moves, so the bevel angle and land stay constant along the edge. How TCP works on H-beam cutting explains the motion.
- Second pass for Y and K. The land, or the second side of a K bevel, is cut as a separate pass in the same program.
Bevel angle and cutting thickness
A beveled cut goes through more steel than a square cut. The length of the cut through the flange is the thickness divided by the cosine of the bevel angle, so steeper bevels need more power and slower speeds.
| Bevel angle | 15° | 30° | 37.5° | 45° |
|---|---|---|---|---|
| Thickness factor | ×1.04 | ×1.15 | ×1.26 | ×1.41 |
| 10 mm flange | 10.4 mm | 11.5 mm | 12.6 mm | 14.1 mm |
| 20 mm flange | 20.7 mm | 23.1 mm | 25.2 mm | 28.3 mm |
| 30 mm flange | 31.1 mm | 34.6 mm | 37.8 mm | 42.4 mm |
Square cutting goes up to 40 mm on the 20 kW configuration. For thick flanges with steep bevels, choose the power on the bevel thickness, not the plate thickness, and confirm with a test cut on your section. The power guide compares 12, 20 and 30 kW.
Laser, plasma or milling
| 5-axis laser | Plasma bevel head | Milling / hand flame + grinding | |
|---|---|---|---|
| Bevel types | V, Y, K | V, Y, K | Any, one edge at a time |
| Angle consistency | Held by TCP along the edge | Good, wider kerf | Depends on operator or setup |
| Heat-affected zone | Narrow | Wider | None for milling, wide for flame |
| Same setup as copes and holes | Yes | Yes | No, separate station |
| Rework before welding | Little or none | Often light grinding | Grinding for flame cuts |
For plate beveling rather than beams, see the gantry plasma bevel cutting machine.
Questions
What bevel angles can the machine cut?
Any angle from 0 to 45 degrees either side of square, set per edge in the part program. The 5-axis head tilts to the angle and holds it as it follows the flange or web.
What is the difference between V, Y and K bevels?
A V bevel is a single angled cut through the full thickness. A Y bevel leaves a straight land, or root face, at the bottom of the bevel. A K bevel is beveled from both faces, which halves the weld volume on thick flanges.
Can the laser leave a root face?
Yes. A Y bevel is cut as two passes: the angled bevel and a square cut for the land. The land height is set in the program, so it stays the same along the whole edge.
Does beveling reduce the maximum thickness?
Yes. At an angle the beam passes through more steel than the plate thickness: about 1.41 times at 45 degrees. A flange that cuts easily square may need a test cut before it is beveled at 45 degrees.
Do I still need to grind after laser beveling?
Usually only to remove light oxide where the welding procedure asks for bright metal. The bevel angle and land come off the machine within tolerance, so there is no grinding to shape.
Can bevels, copes and access holes be cut in one setup?
Yes. The cope, the weld access hole and the flange bevel for a moment connection are all in one program, so the beam is loaded once.
Send a joint detail for a bevel test cut
Machine specifications and power options: H-beam laser cutting machine. Section dimensions: steel beam size chart.
