Carbon steel

Weld Chart

Set the metal, the joint, the position, and the laser kW. Compare rate, heat, and whether the process belongs.

A36 / 1018

½″

12.7 mm · ⅜″ fillet

Laser source

Material

Range

Position

You care about

Plate stock. Fillet leg equals thickness up to ⅜″. Groove below ¼″ is a square butt.

At this joint

MIG

At ½″ carbon steel, ⅜″ fillet, flat, MIG is the pick. 1.4 min/ft, 11 lb/hr, 3 passes. FCAW is 1.2 min/ft. MIG needs still air.

What each process can actually weld

Axis is weld size — fillet leg, or groove thickness. The bright band is plate stock. Solid bar is production fill. Fade is “it will join, this is not the fill process.”

Plate0¼″1″2″TIGLaserL-wireMIGFCAWStickSAW

White dot is the weld size for this joint. Arrow means the process continues past this axis.

Joint rate across thickness

Flux-core overtakes MIG around ¼″ on carbon steel fillet. TIG stays slow. Stick is the outdoor spare.

  • TIG
  • Laser
  • L-wire
  • MIG
  • FCAW
  • Stick
  • SAW

Rate vs heat

Upper right is faster and cooler. Dots move with thickness, joint, and position.

Cooler is up · feet of joint per hour is right

Fast and cool020405550100121Joint rate, ft/hTotal heat, kJ/in of jointTIGMIGFCAWStick

The bead, in section

Stacked passes fill the joint. The band under the bead is heat into the parent metal. Autogenous laser is one keyhole pass. Sub-arc, flux-core, and stick leave slag you cannot see here.

How each process welds

TIG

A tungsten arc melts the joint. You add filler with the other hand. Slow, clean, no slag. The process for thin metal, stainless, aluminum, and roots.

Laser

A focused fiber beam opens a keyhole and the parent metal fuses behind it. No filler. Square edge, gap under about 10% of thickness. One pass if you have the kW. A V-groove still needs wire.

Laser + wire

Same keyhole, with a cold wire in the pool. Fills a small gap and builds a small fillet. Deposition is modest — a robot feeder, not a MIG gun. Handheld wobble feeders put down less than these numbers.

MIG

A wire feeds through a gun. Short-circuit on sheet and out of position. Spray or pulse on thicker plate in the flat. Needs still air — wind blows the gas off.

Flux-core

A tubular wire with flux inside. High deposition, all-position with the right wire, and it does not mind mill scale. Self-shielded wire is the field process. Not for aluminum.

Stick

A coated electrode. Works in the wind, on rusty steel, in a ditch. Slow, slag, and you stop to change rods. The field and repair process. Aluminum stick exists on paper, not in a production shop.

Sub-arc

The arc runs under a pile of flux. A tractor or a column follows a long straight seam. Huge deposition, almost no fume, a flat bead. Flat and horizontal only. Not a short fillet, and not aluminum.