Sorry to have to break it to you, but the welding table industry has built a billion-dollar marketing narrative around a surface treatment that physically cannot do what they say it does. They are just plain LYING! Let’s take it apart, claim by claim, using the manufacturers’ own words and the metallurgy they’re clearly hoping you never look up.
The Lies Being Presented
There are several vendors presenting some variation of the same story: Siegmund (via their US distributor Quantum Machinery) puts it bluntly on their blog:
“By choosing to get a Welding Table that is plasma-nitrided, you get 6 HUGE Beneficial Factors not available anywhere else. Our Plasma Nitrided Welding Tables are: 1. Spatter-Proof 2. Rust-Proof 3. Deep Scratch-Proof 4. The Plasma Nitration also makes the Welding Table, as a whole, much, much stronger.”
StrongHand Tools, on their Alpha 28 product line, echoes the same script:
“QPQ Nitriding adds a 58–62 HRC hardened, corrosion- and spatter-resistant surface for lasting durability and easy cleanup.”
And on their BuildPro MAX line:
“The nitriding (heat-treating) process is a mechanical polish and post salt bath oxidative treatment. The benefits of this process include weld spatter resistance and corrosion and wear resistance.”
Siegmund’s main materials comparison page doubles down further, claiming plasma nitriding increases “the loadability of the table by approx. 20-30%” and that “plasma nitration is always profitable.”
These are not subtle implications buried in fine print. These are the headline claims driving purchase decisions on tables that cost $3,000 to $15,000+. So let’s examine each one against what plasma nitriding actually is, physically and chemically, and see how many of these claims survive contact with metallurgical reality.
The Physics of Plasma Nitriding
Before we can evaluate any of these claims, we need to establish exactly what the process produces at the material level. Not the marketing version. The actual thermochemistry.
Plasma nitriding (also called ion nitriding or glow-discharge nitriding) is a thermochemical surface treatment performed in a vacuum chamber. The workpiece is made the cathode in an electrical circuit. A mixture of nitrogen and hydrogen gas is introduced at low pressure (typically 1-10 mbar). A high DC voltage (300-1000V) is applied between the chamber wall (anode) and the workpiece (cathode), generating a glow discharge plasma around the surface. Nitrogen ions in this plasma are accelerated toward the workpiece surface by the electric field, where they are implanted into the metal lattice via ion bombardment and subsequent thermal diffusion.
The result is two distinct zones beneath the surface:
The compound layer (also called the white layer): A thin outermost layer of iron nitride phases, primarily ε-Fe₂₋₃N and γ′-Fe₄N. This is the hard, nitrogen-rich layer that provides wear resistance. Its thickness is the critical number for this entire discussion.
The diffusion zone: A deeper gradient beneath the compound layer where dissolved nitrogen atoms have diffused into the iron lattice without forming discrete nitride phases. This zone contributes to residual compressive stress (beneficial for fatigue resistance) and a gradual hardness transition from surface to core.
The Layer Thickness Lie
Here is where the marketing narrative collides with physics, and the marketing loses.
The compound layer produced by plasma nitriding is extraordinarily thin. Published research data and industrial process specifications consistently place it in the range of 4 to 20 microns for standard industrial applications. That’s 0.004 to 0.020 millimeters. To put that in perspective: a single sheet of standard copy paper is approximately 100 microns thick. The nitrided compound layer on a welding table is, at best, one-fifth the thickness of a piece of paper.
Bodycote, one of the world’s largest heat treatment service providers, confirms this on their plasma nitriding service page, describing layers “up to 20 microns thick.“
Academic research on AISI 4340 steel plasma nitriding confirms compound layers of “4.5-7 μm thick” with diffusion zones extending to 90-240 microns depending on time.
Thermal Processing Magazine, citing research on compound zone kinetics, documents saturation behavior in plasma nitriding where the compound layer reaches approximately 13-14 microns and growth essentially stops.
StrongHand actually gives away a critical number on their Alpha 28 spec sheet. They state their nitride coating has “a case depth of .0004-.0008″” — that’s 10 to 20 microns. This is not a typo. This is the actual thickness of the protective layer on a table that costs thousands of dollars and is marketed as “rust-proof” and “deep scratch-proof.”
The Physics of the Lie
The entire “deep scratch-proof” claim hinges on a layer that’s 1/5th the thickness of copy paper. If you made a 1 square foot sheet of just this magic hard coating material, nothing underneath it, a 1/4″ ball bearing that weighs a single gram dropped from waist height would shatter it on impact.
The reason the nitrided table surface doesn’t instantly shatter when you drop a wrench on it isn’t because the coating is tough. It’s because the soft carbon steel substrate underneath absorbs the impact by yielding (denting). The hard coating rides along with the substrate deformation, cracking as it goes.
This is the fundamental lie in “deep scratch-proof”: they’re conflating surface hardness (resists abrasive scratching) with impact resistance (resists denting/fracturing from dropped tools). Iron nitride has high hardness but extremely low fracture toughness, classic brittle ceramic behavior. Hard ≠ tough.
Now let’s take that number, 10 to 20 microns, and hold it against each marketing claim.
The Marketing Claims
Claim 1: “Rust-Proof”
Siegmund (Quantum Machinery): “Rust-Proof” StrongHand: “corrosion resistant” Siegmund materials page: “protection against scratches, corrosion, and the adhesion of weld spatter”
This is the most dangerous claim in the entire portfolio, because it is the one most likely to influence a purchasing decision based on long-term service life, and it is the one most thoroughly refuted by the underlying chemistry.
What’s Actually Happening at the Corrosion Level
The compound layer (ε-Fe₂₋₃N / γ′-Fe₄N) does have corrosion resistance superior to bare carbon steel. This is not disputed. The iron nitride phases are thermodynamically more stable than bare iron in the presence of oxygen and water, and they do present a barrier to the electrochemical processes that produce rust.
However, this barrier is a 10-20 micron film on a fully ferrous substrate. The substrate beneath that film is carbon steel. It has zero intrinsic corrosion resistance. The moment that film is breached, by a scratch, a weld spatter impact, a dropped tool, a clamp edge, grinding debris, or any mechanical event that penetrates 20 microns of depth, bare carbon steel is exposed to the atmosphere, and rust begins immediately.
Siegmund appears to acknowledge this implicitly by layering a second treatment on top: the BAR coating (Black-Anti-Rust Coating), which is an additional oxide layer applied after nitriding. This is essentially an admission that the nitride layer alone is not sufficient corrosion protection.
The QPQ Process and Its Actual Corrosion Mechanism
StrongHand’s Alpha 28 line specifies QPQ (Quench-Polish-Quench) nitriding rather than straight plasma nitriding. QPQ is a salt-bath nitrocarburizing variant that adds a post-oxidation step, producing a surface layer of magnetite (Fe₃O₄) on top of the nitride compound layer. This magnetite layer does improve corrosion resistance significantly over bare nitriding.
But Fe₃O₄ is still an iron oxide. It is not a passive, self-repairing chromium oxide layer like the one found on stainless steel. It is a barrier coating. Research on QPQ-treated 1020 steel documents corrosion resistance “up to ~400 hours” in ASTM B117 salt spray testing under optimal conditions.
400 hours of salt spray resistance sounds impressive until you realize that ASTM B117 is a controlled laboratory test specifically designed to accelerate corrosion. Real-world shop environments, with cutting fluid splatter, humidity cycling, condensation, and mechanical abrasion happening daily, do not replicate salt spray conditions. They replicate something arguably worse: chronic, low-level exposure combined with constant mechanical disruption of the surface film.
“Rust-Proof” vs. Reality
A table marketed as “rust-proof” with a 10-20 micron barrier coating on a carbon steel substrate will rust. It will rust the first time a tool gouges deep enough to breach that film. It will rust at every borehole edge where the nitriding coverage is thinnest (plasma nitriding has known coverage uniformity issues at edges and complex geometries). It will rust at every weld point, every clamped edge, every location where the surface has been mechanically disrupted.
Calling this “rust-proof” is not a stretch of marketing language. It is a factually false claim about the fundamental material chemistry of the product.
Claim 2: “The Plasma Nitration Also Makes the Welding Table, as a Whole, Much, Much Stronger”
This claim, made directly by Siegmund/Quantum Machinery, is a textbook example of conflating surface properties with bulk mechanical properties.
What Plasma Nitriding Actually Strengthens
Plasma nitriding increases surface hardness and fatigue resistance (via compressive residual stress). These are real effects, well-documented in metallurgical literature. They are also confined to the surface zone, the compound layer and the shallow diffusion zone beneath it.
The bulk mechanical properties of the table, tensile strength, yield strength, impact resistance, load-bearing capacity, are determined by the base material’s composition, grain structure, and heat treatment condition through the entire cross-section. A 25mm thick table plate has its structural properties determined by 25mm of steel. The top 0.02mm of that plate being harder does not change what happens when a load is applied to the other 24.98mm.
The “20-30% Loadability Increase” Claim
Siegmund’s materials comparison page states: “the loadability of the table is increased by approx. 20-30%.”
As I previously said, increasing the load-bearing capacity of a table by 20-30% through plasma nitriding is completely impossible without structural modifications. Surface hardening can improve wear resistance but in no way enhances the inherent load-bearing capacity of structural components.
A 20-30 micron surface treatment cannot increase the structural load-bearing capacity of a plate by 20-30%. The math doesn’t work. Load-bearing capacity scales with cross-sectional area, material yield strength through that area, and support geometry. None of those parameters are meaningfully altered by a surface film that is 0.1% of the plate thickness. It’s just like the hard candy shell of an M&M. Easy to get through, especially with the soft middle.
The only scenario in which surface hardening contributes to “loadability” in any meaningful sense is if the surface is the failure point, for example, in a fatigue-cycled component where surface cracks initiate failure. A welding table plate under static or quasi-static distributed loading does not fail by surface crack initiation. It fails by yielding through the bulk, by deflection, or by fracture at stress concentrators. Plasma nitriding addresses none of these failure modes in a meaningful way for this application.
Claim 3: “Spatter-Proof”
This is the one claim that has a legitimate technical basis, but even here, the language overshoots the reality.
Plasma nitriding does reduce weld spatter adhesion. The mechanism is well-established: the iron nitride surface has a lower surface energy than bare carbon steel, which reduces the wetting and bonding of molten iron droplets. This is a real and useful property for a welding table.
But “spatter-proof” implies zero adhesion. In practice, plasma-nitrided surfaces still accumulate spatter, particularly from high-energy processes like MIG welding with high wire feed rates, or from any spatter event that impacts the surface with enough energy to mechanically deform both the spatter and the underlying material. The nitrided surface makes cleanup easier. It does not make spatter physically unable to adhere.
Siegmund’s own materials page uses more measured language elsewhere: “Welding spatter adheres significantly less to a table with plasma nitriding than to welding tables without plasma nitriding.” That’s an honest claim. “Spatter-Proof” is not.
Claim 4: “Deep Scratch-Proof” and Maintaining Flatness
Siegmund/Quantum Machinery claims their tables are “deep scratch-proof” and that plasma nitriding “allows our Welding Tables to maintain a flatness that [is] un-achievable in the long-term by any other Welding Table Manufacturers.”
The surface hardness numbers cited by Siegmund (750 HV on the top surface for X7 material, up to 850 HV after BAR treatment) are genuinely impressive hardness values. A 750 HV surface will resist scratching from most hand tools and light impacts.
But here is the critical mechanical failure mode that “deep scratch-proof” conceals: the substrate beneath the hard surface yields before the surface fails.
Consider what happens when a heavy workpiece is set down hard on the table, or when a clamp applies a concentrated point load, or when a chunk of slag strikes the surface at velocity. The force transmits through the 10-20 micron hard compound layer into the base material beneath it. If that base material is softer than the surface (and it always is, that’s the entire point of case hardening), it deforms plastically at a stress level well below what would crack the surface layer. The result is a dent in the substrate with the hard surface layer sitting on top of it, either cracked or deformed along with the substrate.
This is not a theoretical failure mode. It is the expected behavior of any hard-on-soft layered system under impact loading. It is the same reason that chrome plating on brass eventually fails, why hard anodizing on aluminum cracks at sharp bends, and why case-hardened gear teeth can suffer “spalling” where the hard case separates from the softer core.
The surface hardness of a plasma-nitrided table does not prevent denting. It prevents scratching from light abrasive contact. Those are fundamentally different failure modes, and conflating them is misleading.
As for flatness: a plasma-nitrided surface does not “maintain flatness.” Flatness is a function of the bulk material’s rigidity, the structural support beneath the plate, and the thermal and mechanical loading history of the table. A 10-20 micron surface treatment has no meaningful contribution to any of those factors.
Claim 5: “The Ability to Use the Table with Stainless Steel Applications”
Siegmund’s FAQ states that plasma nitriding provides “the ability to use the table with stainless steel applications.”
This claim implies that a plasma-nitrided carbon steel table is suitable for welding stainless steel workpieces without cross-contamination concerns. This is metallurgically incorrect.
The nitrided surface is still iron. It is iron nitride (Fe₂₋₃N / Fe₄N), but the dominant element is iron. Any mechanical interaction between the table surface and a stainless steel workpiece — sliding, grinding, clamping, or even just resting under load — can transfer iron particles from the table surface to the workpiece. Iron contamination on a stainless steel weld joint is a corrosion initiation site. It defeats the purpose of using stainless steel in the first place.
A genuinely contamination-free surface for stainless steel fabrication requires a material that has no free iron at the surface. That means actual stainless steel, or a material with an inherently passive oxide layer that reforms after mechanical disruption. A carbon steel surface with an iron nitride film does not meet this criterion.
Siegmund’s Related Marketing Lie
This article would be incomplete without addressing the independent material analysis we performed back in October 2024.
We purchased multiple Siegmund 5′ x 10′ Imperial Series welding tables (approximately $10,000 each) and had a sample cut from one table’s rib and sent to an independent metallurgical laboratory for chemical analysis. The result:
“As a low alloy steel the results for that material are not looking like anything very special: 0.12% carbon is low and not really heat treatable much. 0.6% Mn. Low P and low S. Cr 0.14. Cu <0.05. Si < 0.015. Ni< 0.05. This is barely in the range of 1018 carbon steel.”
AISI 1018 is a low-carbon mild steel. It has a tensile strength of approximately 65 ksi in the annealed condition and is not meaningfully heat-treatable to higher hardness due to its low carbon content (0.12% in this sample, below even the 1018 specification floor of 0.15-0.20%). Siegmund markets this material as “Professional Extreme 8.7 Hardened Tool Steel” with claims of 266-382 HV base hardness.
Note: This analysis was performed on a rib section, not the top plate. Siegmund subsequently contacted me and told me they use different material on the ribs, but has not publicly clarified this! Since this is the case, their marketing – at a minimum – is deeply misleading. So we are compounding deeply misleading claims and perpetrating a fraud on buyers.
The Cost-of-Ownership Calculation
Plasma nitriding is not free. The treatment adds cost to the manufacturing process, and it adds a finite service life expectation to the table surface. When that surface is breached, and on a working fabrication table, it will be breached, the options are: live with the rust, strip and re-treat (expensive and requires disassembly), or replace the table.
If a buyer were truly looking for a surface free from corrosion, they should purchase a stainless steel table like the ones we manufacture. A stainless steel table has no consumable surface layer. It has no re-treatment requirement. It has no breach point. Its corrosion resistance does not degrade over time. Its hardness does not change. Its structural properties do not change. It simply exists as the same material from day one to day 5,000.
The total cost of ownership calculation for a plasma-nitrided carbon steel table versus a stainless steel table of equivalent geometry favors the stainless steel table at any service life beyond the first breach event. For a table that will see daily use in a fabrication shop, that breach event is measured in months, not years.
Summary: What’s True, What’s Exaggerated, and What’s False
| Claim | Verdict | Reality |
|---|---|---|
| Plasma nitriding reduces spatter adhesion | True | Surface energy reduction is real and well-documented |
| Plasma nitriding increases surface hardness | True | 450-750+ HV surface hardness is achievable |
| “Rust-Proof” | False | 10-20 micron barrier on a fully ferrous substrate. Breach = rust |
| “Deep Scratch-Proof” | Exaggerated | Resists light abrasive contact. Does not prevent denting from impact loading |
| “Makes the table much, much stronger” | False | Surface treatment does not alter bulk tensile, yield, or impact properties |
| “Loadability increased 20-30%” | False | Physically impossible for a 0.02mm surface treatment to increase structural load capacity by 20-30% |
| “Maintains flatness” | False | Flatness is a bulk structural property. Surface treatment is irrelevant |
| “Suitable for stainless steel applications” | False | Iron nitride surface still transfers iron contamination to workpieces |
Final Thought
Plasma nitriding is a legitimate and useful surface treatment technology. It has decades of successful application in automotive components, firearms, hydraulic cylinders, and precision tooling, applications where the surface is the primary point of interaction, the loads are well-characterized, and the failure modes are understood.
It is not a substitute for material selection. It is not a substitute for bulk mechanical properties. And it is not, under any physically coherent interpretation, “rust-proof.”
The welding table industry has built a marketing narrative around plasma nitriding that consistently overstates what the process can deliver and consistently understates the failure modes it cannot prevent. If you are evaluating a welding table purchase and “rust-proof” or “much, much stronger” is a factor in your decision, understand exactly what those claims mean at the material level before you write the check.
