S690QL vs Hardox
Two steels, two different purposes. S690QL is a structural high-strength steel — it carries load (yield ≥690 MPa). Hardox is a wear-resistant steel — it resists friction (hardness 400–500 HBW). The right steel is for the right job.
The Core Difference: Strength vs Wear
S690QL and Hardox are often compared, but the two are made to solve different problems. That is why "which is better?" is the wrong question; the right question is "what load does your application see?".
- S690QL — strength steel: it is a quenched and tempered structural steel to the EN 10025-6 standard. Its design is built on high yield strength (≥690 MPa); its purpose is to carry load without permanent deformation of the structure. Its typical hardness is around 235–280 HBW.
- Hardox — wear steel: it is a family of wear-resistant steels and a registered trademark of SSAB. Its design is built on high hardness (Hardox 400 ≈ 400 HBW, 450 ≈ 450 HBW, 500 ≈ 500 HBW); its purpose is to resist abrasive material wearing the surface.
In short: S690QL is optimized for strength, Hardox for wear resistance. Where one is strong the other is weak — S690QL excels in structural load-bearing members, Hardox on wearing surfaces.
Overview
S690QL — Structural Strength Steel
It is a high-strength structural steel produced to the EN 10025-6 standard. Its core purpose is to carry load. Thanks to its high yield strength, a lighter and stronger structure can be built with thinner sections. It offers good weldability, high impact toughness and favorable bending capability. It is used in crane booms, chassis, bridges and pressure vessel components.
Hardox — Wear-Resistant Steel
It is a registered family of wear steels produced by SSAB. Its core purpose is to provide wear resistance. Thanks to its high hardness (Hardox 400/450/500), it delivers long service life under abrasive material. As hardness increases, welding and bending become harder and ductility decreases. It is used in tipper liners, bucket edges, crusher and bunker liners.
Full Comparison Table
A side-by-side comparison of S690QL structural strength steel and Hardox wear steel (grades 400 and 450). The highlighted rows are the points where the two steels diverge most clearly.
| Property | S690QL | Hardox 400 / 450 |
|---|---|---|
| Steel type | Structural high-strength steel | Abrasion resistant (AR) steel |
| Main purpose | Load carrying / strength | Wear & friction resistance |
| Standard / source | EN 10025-6 | Registered brand (SSAB) |
| Yield strength (ReH) | ≥ 690 MPa | ≈ 1000 MPa (typical, not guaranteed) |
| Tensile strength (Rm) | 770 – 940 MPa | ≈ 1250 MPa (typical) |
| Hardness (HBW) | 235 – 280 HBW | Hardox 400 ≈ 400 · Hardox 450 ≈ 450 HBW |
| Impact toughness | ≥ 30 J at −40°C (guaranteed) | ≈ 30 J at −40°C (typical, depends on grade) |
| Typical use | Chassis, crane boom, bridge, pressure vessel | Tipper liner, bucket edge, crusher liner |
| Forming (bending) | Good — suitable for cold bending | Limited — difficult due to high hardness |
| Weldability | Good — low-hydrogen method | Difficult — preheat and strict procedure required |
Note: S690QL values are the EN 10025-6 guaranteed minimums. Hardox values are typical values based on SSAB data sheets; since in wear steels yield/tensile are not guaranteed and hardness is the key characteristic, these rows are for reference. Hardox 500 ≈ 500 HBW is even harder but welding/bending is more critical.
Which Should I Choose?
The choice depends on the dominant load the part sees. The three scenarios below let you quickly identify the right material:
Load-Bearing / Structural Load → S690QL
If the part carries load, works under bending/tension/compression stress and lightness matters, choose S690QL. Example: crane boom, machinery chassis, bridge girder, pressure vessel, steel construction.
Wear / Friction / Impact Surface → Hardox
If the surface contacts abrasive material, rubs continuously or takes impact, choose Hardox. Example: tipper body liner, excavator bucket edge, crusher liner, conveyor chute, mining bunker lining.
If You Need Both → Combination
If the part both carries load and wears, use a combination: the load-bearing body in S690QL, the wearing surfaces in Hardox liner. This common solution provides both structural integrity and long service life.
Wear Resistance vs Strength
The two concepts are often confused, but they measure different material properties:
Strength (Yield Strength)
It is how much load the material can withstand without permanent deformation; it is measured by yield strength in MPa. Higher yield = more load with a thinner/lighter section. S690QL is designed for this property. Strength is the part's resistance to bending/breaking.
Wear Resistance (Hardness)
It is how well the material surface resists scratching, friction and abrasive material; it is measured by hardness (HBW Brinell). Higher hardness = slower wear, longer service life. Hardox is designed for this property. Wear resistance is the surface's resistance to thinning over time.
High hardness usually means lower ductility and harder welding/bending. That is why using a very hard wear steel in a load-bearing structure is risky; conversely, using a soft structural steel on a wearing surface leads to rapid wear. The right material = the right property, in the right place.
Using Both Together
In many heavy industrial applications, S690QL and Hardox are used together: S690QL carries the structural frame, Hardox protects the wearing surfaces. Typical examples:
Tipper Body
Chassis and load-bearing profiles in S690QL; floor and side liners in Hardox 450/500. The structure stays light while wear life is extended.
Excavator Bucket
Bucket body in S690QL for strength and impact toughness; bucket edge and cutting edges in Hardox for wear resistance.
Crusher & Screening
Frame and body in S690QL; the inner liners the material rubs against in Hardox 500 as replaceable plating.
Concrete Mixer / Pump
Load-bearing parts in high-strength steel; inner surfaces in contact with abrasive concrete lined with wear steel.
Supply Note
Sacdan Adam supplies both high-strength structural steels (S690QL, S700MC, Strenx 700E, DILLIMAX 690T) and wear-resistant steels (Hardox and equivalent AR grades). The right grade matching, cutting and bending services are delivered together from a single source.
Frequently Asked Questions
Is S690QL wear-resistant?
S690QL offers limited wear resistance. Its typical hardness is 235–280 HBW, harder than standard structural steel S355 (≈160 HBW) but clearly below the wear steels (Hardox 400 ≈ 400 HBW).
S690QL is optimized for structural strength rather than wear resistance. On surfaces exposed to heavy abrasive load, continuous friction or material flow, wear steels above 400 HBW such as Hardox should be preferred.
Can Hardox be used in structural load-bearing members?
It is generally not recommended. Hardox is produced at high hardness for wear resistance; this creates disadvantages in terms of the weldability, ductility and ease of forming required in load-bearing structures.
For load-bearing structural members, structural high-strength steel such as S690QL is the standard. SSAB's high-toughness structural wear grades such as HiTuf may be an exception, but for classic chassis/boom/bridge applications S690QL is the right choice.
Which one is used in a tipper body?
In tipper bodies the two are usually used together:
- Chassis and load-bearing profiles: S690QL high-strength steel — structural strength and lightness.
- Floor and side liners: Hardox 450 or Hardox 500 — wear resistance on surfaces where the material rubs.
This combination provides both structural soundness and long wear life together.
Which is harder, Hardox or S690QL?
Hardox is significantly harder. Hardness comparison (reference HBW):
- S690QL: ≈ 235–280 HBW
- Hardox 400: ≈ 400 HBW
- Hardox 450: ≈ 450 HBW
- Hardox 500: ≈ 500 HBW
But hardness alone does not mean "better": Hardox is optimized for hardness/wear resistance, while S690QL is optimized for yield strength/structural load. The right steel is chosen according to the load the application sees.
Let's Choose the Right Steel for Your Project Together
Structural strength, wear resistance, or both? Sacdan Adam supplies both S690QL high-strength and Hardox wear steels from stock. Get in touch for the right grade and combination.