Technique & material
Gas nitriding: why a nitrided welding table is better
Nitrided, hardened, 800 HV: terms you see on product pages, but what do they mean for your work? This guide explains what gas nitriding is and why it makes the difference between a welding table that stays flat for years and one that wears out fast.
Short answer
Gas nitriding is a heat treatment in which nitrogen diffuses into the steel surface and hardens it from the inside out to around 800 HV. It is not a coating: there is no layer on top that can flake off. A nitrided welding table stays flat longer, weld spatter sticks less and the surface transfers nothing onto your workpiece.
What exactly is gas nitriding?
Gas nitriding is a thermochemical treatment that brings nitrogen into the outer layer of the steel and hardens that layer.
During gas nitriding the steel is brought up to temperature in a furnace with a nitrogen-rich atmosphere. The nitrogen diffuses into the surface and forms hard compounds within the steel itself. So no material is applied or added: the existing steel is made harder.
DCT welding tables are gas-nitrided this way to a surface hardness of around 800 HV. The clamping tools get a QPQ nitriding, which adds corrosion protection alongside hardness.
Why nitriding is not a coating
With a coating you put a layer on the steel; with nitriding you change the steel itself.
A paint or powder coating is a separate layer on top of the metal. That layer can scratch, peel or burn under the heat of welding and the impact of spatter. Once the coating is damaged, the soft steel underneath is exposed.
A nitrided layer, by contrast, sits within the steel. There is nothing to flake off, and the layer withstands welding heat and spatter. As a result the top plate stays hard and flat, and transfers nothing onto your workpiece.
- Coating: a layer on top, can peel, scratch or burn under welding heat
- Nitriding: part of the steel, doesn't flake off, resists spatter
What do you notice in practice?
A nitrided top plate stays flat, weld spatter comes off easily and the surface barely wears.
Because the surface is so hard, grinding discs, clamps and spatter leave almost no marks. The plate keeps its flatness, which keeps your clamping accurate, and it's easy to clean. In the end a nitrided table lasts years longer than an untreated or coated plate.
- Weld spatter barely sticks and comes off easily
- Fewer pits and less wear from grinding discs and tools
- The top plate stays flat, so your clamping stays accurate
What does 800 HV mean?
HV stands for Vickers hardness; 800 HV approaches the hardness of hardened tool steel.
Hardness is a material's resistance to scratches and indentation. Untreated steel is considerably softer, while a nitrided surface of around 800 HV comes close to hardened tool steel. That hardness is exactly why the top plate keeps its flatness and doesn't damage quickly.
And the clamping tools?
DCT clamping tools are nitrided too, so clamps, bolts and stops last as long as the table.
There's little point pairing a rock-hard top plate with soft tools that wear out fast. That's why DCT clamping tools are QPQ-nitrided. Alongside hardness, that treatment adds good corrosion protection, so your table and tools keep the same lifespan and quality.
Nitrided vs coated vs untreated
| Feature | Nitrided | Coated / painted | Untreated |
|---|---|---|---|
| Surface hardness | Very high (± 800 HV) | Soft (layer on top) | Low |
| Flakes off | No, sits in the steel | Yes, with wear or heat | Not applicable |
| Weld spatter sticks | Barely | Can burn in | Strongly |
| Transfer onto workpiece | No | Possible | Rust possible |
| Stays flat | Yes, for years | Variable | Wears faster |
Frequently asked questions
With coating you put a layer of material on the steel, which can peel or burn under welding heat. With nitriding, nitrogen diffuses into the steel itself and hardens it from the inside out. That hard layer does not flake off and resists weld spatter.
The surface of a nitrided DCT welding table is around 800 HV (Vickers). That approaches the hardness of hardened tool steel and is considerably harder than untreated steel, so the top plate barely wears.
No. Because the nitrided layer is part of the steel and not a loose coating, nothing comes off that could deposit on your workpiece. That matters for visible work and for welding where you want a clean surface.
Much less than to untreated steel. Weld spatter barely sticks to the hard, smooth nitrided surface and comes off easily, so your top plate stays flat and clean.
Yes. DCT clamping tools are QPQ-nitrided, which adds corrosion protection alongside hardness. So clamps, bolts and stops last as long as the table.
Want to judge the quality yourself?
Take a look at DCT's nitrided welding tables or request advice with no obligation. In stock, with fast delivery across Europe.
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