Is nitriding a coating?

No. Nitriding diffuses nitrogen into the steel surface and hardens the material itself. There is no added layer, so nothing can peel or flake, and no film is left on the workpiece.

Does nitriding change the hole size?

The grid is machined before the treatment, so holes and spacing keep their specified dimensions. Tables are available in 16, 22 and 28 mm hole systems with the same options as the untreated range.

Will the dark surface mark the parts I weld?

The colour comes from the treated steel surface, not from a pigment or coating, so there is no transfer to the part. The darker finish also reduces glare compared with a bright machined surface.

Is a nitrided table harder to repair?

The hardened case is thin relative to the plate, and the plate beneath is the same steel as an untreated table. For a localised issue the practical approach is agreed with the supplier based on the damage; confirm the approach before any rework.

Nitrided Welding Table: What the Surface Treatment Actually Does

What "nitrided" means on a welding table

Nitriding is a heat treatment that diffuses nitrogen into the steel surface, producing a hard, wear-resistant layer. It is not a paint or coating, so there is no film that can flake off or transfer to the workpiece. On a welding table it protects the machined faces and the hole grid where clamps and pins are used every shift, so the working accuracy lasts longer.

Who this is forBuyers comparing a plain machined table against a nitrided table, and engineers checking what the treatment does

The process in one paragraph

The table is machined first. It is then held at temperature in a nitrogen-bearing atmosphere, and nitrogen diffuses into the surface of the steel. The result is a hardened case that is part of the material rather than an applied layer. In our tables the nitriding hardness range is HV450 to HV630.

Because the treatment follows machining, the hole grid and the working faces keep their dimensions. You are not choosing between a machined surface and a nitrided surface — the surface is machined, and then nitrided.

What it changes in daily use

Wear at the hole grid. Clamps and pins are inserted and removed constantly, and that is where a table loses accuracy first. A hardened surface resists that wear.
Wear on the working faces. Parts being dragged, tacked and clamped mark a soft surface over time.
Glare under shop lighting. The dark surface reflects less light than a bright machined finish, which some operators prefer when working over the table.
Corrosion resistance. The treated surface is less prone to surface rust than an untreated machined face, though the table still benefits from normal care.

When a machined surface is enough

Nitriding adds cost, so it is not automatically the right answer. If the table is used occasionally, or for light work with modest clamping force, a milled or ground surface is sufficient and the money is better spent on the correct hole system or on tooling.

The case for nitriding is strongest where the table is a production asset: a fixture station used every shift, where clamping is frequent and the table has to hold its accuracy for years. There the wear resistance pays for itself by postponing the day the grid has to be reworked.

Questions worth asking a supplier

Is the treatment applied before or after machining? After machining means the grid keeps its dimensions.
Is it nitriding or a painted or coated finish? A coating can chip and is a different proposition entirely.
What hardness range is achieved? Ours is HV450 to HV630; another supplier may differ, so ask for the figure.
Which surfaces are treated? Working faces and holes are the ones that matter.

What "nitrided" means on a welding table

The process in one paragraph

What it changes in daily use

When a machined surface is enough

Questions worth asking a supplier

Where to go next

Questions on this topic

Turn your next setup into a repeatable system.