Industry Applications
Where and why is high-strength steel (S690QL and S700MC) used? From cranes to trailers, from mining to bridges: real-world sector uses and the concrete gains they deliver.
Why High-Strength Steel?
The core advantage of high-strength steels is simple: achieving the same strength with less material. When S690QL or S700MC, with roughly twice the yield strength, is used instead of standard structural steel like S355, the section thickness required for the same design load can be significantly reduced. This means roughly 30–40% weight reduction in the load-bearing structure, higher payload, and lower transport/assembly cost.
There are two main product families, and sector preference mostly leans toward one of them:
For thick sections (8–120 mm), high toughness, and heavy load-bearing parts. It stands out in thick and critical parts such as crane booms, excavator buckets, bridges, and pressure vessels.
For thin sections, superior cold forming, and series production. Ideal for trailer chassis, tipper bodies, profiles, and bending-intensive parts; it offers a smooth surface and tight tolerances.
Cranes & Lifting Equipment
In cranes, every kilogram matters. The boom's (lifting arm) own weight directly reduces the net load that can be lifted. Producing a thinner-walled, lighter boom with high-strength steel provides longer reach or higher lifting capacity with the same crane. Mobile crane booms, tower crane jibs, telescopic booms, and chassis/counterweight connections are designed with this logic.
Because boom sections are thick and work under dynamic (cyclic) loads, both high yield and good toughness are required. For this reason, S690QL is preferred in cranes; it offers balanced strength/toughness even in thick sections and a −40°C impact guarantee. S700MC can be considered for secondary parts such as cabins and cladding that use thin plate.
| Part | Recommended Grade | Expected Gain |
|---|---|---|
| Telescopic boom section | S690QL | Light boom → long reach / high capacity |
| Main chassis & connection plates | S690QL | High strength, compact section |
| Cabin / cladding (thin plate) | S700MC | Easy forming, lightness |
Recommended grade: S690QL for booms and main load-bearing members (S690QL1 for −60°C if required). Among brands, Strenx 700E is frequently used.
Mining & Heavy Machinery
Mining equipment is exposed to both heavy mechanical loads and constant impact/abrasion. Excavator buckets, tipper bodies, crusher housings, loader buckets, and conveyor frames demand high strength; at the same time, keeping the machine's own weight at the limit is important for fuel consumption and payload.
Here, two needs combine: structural strength and wear resistance. S690QL is used in load-bearing bodies and sections that must not bend under load; on surfaces most exposed to abrasion, such as the bucket lip and base plate, it is combined with Hardox-type wear steel. In parts where structural strength comes before abrasion, S690QL is the right choice.
| Part | Recommended Grade | Priority |
|---|---|---|
| Tipper body main structure | S690QL | Strength + weight |
| Excavator bucket body | S690QL | Structural strength |
| Bucket lip / base wear surface | Hardox (combined) | Wear resistance |
| Conveyor / machine frame | S690QL | Rigidity + lightness |
Recommended grade: S690QL for the structural body; a combined design with Hardox on wear surfaces. See our comparison page for the difference between S690QL and Hardox.
Structural Steel & Bridges
In long-span bridges, stadium roofs, high-rise steel frames, and wide-span industrial structures, the largest load is often the structure's own weight. Using high-strength steel reduces the section of load-bearing members; this lowers both the dead load and the foundation and support loads, providing cascading cost savings.
Since bridge girders, truss system members, and main load-bearers are usually thick-section and under fatigue loading, S690QL is preferred; safe connections are made thanks to its good toughness and weldability. It must be remembered that buckling and fatigue control become more critical in high-strength steel in design.
| Application | Recommended Grade | Expected Gain |
|---|---|---|
| Bridge main girder (long span) | S690QL | Thin section → low dead load |
| Truss system members | S690QL | Light load-bearer, compact node |
| Wide-span roof trusses | S690QL | Less steel tonnage |
Recommended grade: S690QL for main load-bearers. A project calculation is essential for fatigue and buckling control.
Energy
The energy sector is one of the areas where thick, high-strength, and reliable steel is used most intensively. As wind turbine towers grow taller and reach larger blade diameters each year, the tower wall must keep its weight at the limit while also withstanding wind load and fatigue. In pressure vessels, hydroelectric gates, and pipelines, internal pressure and safety factors demand thick yet high-strength plate.
Because thickness and toughness come to the fore in these applications, S690QL is the main preference. For thin-section tower segments or some series-manufactured components, S700MC can also be considered to benefit from the cold-forming advantage. We remind you that pressure vessel applications require grades and certification compliant with the relevant pressure equipment standards.
| Application | Recommended Grade | Priority |
|---|---|---|
| Wind turbine tower (thick segment) | S690QL | Strength + fatigue |
| Wind tower (thin segment) | S700MC | Forming + lightness |
| Pressure vessel / boiler body | S690QL | Pressure strength + toughness |
| Hydroelectric gate / pipe | S690QL | Thick-section strength |
Recommended grade: Mostly S690QL; S700MC for thin/series parts. Standard and certification checks are mandatory for pressure equipment.
Marine & Offshore
Ship hulls, offshore platforms, floating cranes, and marine structures are continuously exposed to dynamic wave loads and low temperatures. In cold seas and polar waters, the most critical property expected from steel is sufficient impact toughness against brittle fracture at low temperatures.
For this reason, S690QL and especially S690QL1 (min. 27 J at −60°C), which provides a lower temperature guarantee, are preferred in marine/offshore applications. While high strength reduces hull weight to deliver fuel efficiency and load capacity, guaranteed low-temperature toughness ensures safety in marine conditions. Classification society (class) approved grades must be used.
| Application | Recommended Grade | Decisive Property |
|---|---|---|
| Cold-climate hull / platform | S690QL1 | −60°C impact toughness |
| General hull structure | S690QL | −40°C toughness + lightness |
| Floating crane load-bearers | S690QL | Strength + weight |
Recommended grade: S690QL / S690QL1. For low-temperature operation, confirm the L1 grade and class approval.
Trailers & Transport
In road transport, the biggest constraint is the legal axle and total weight limits. The lower the trailer's empty weight (tare), the more load that can be carried within the limits. That is why trailer chassis, tipper bodies, low-bed platforms, and tanker bodies are lightened with high-strength steel; every kilogram of tare reduction converts directly into profit.
Trailer parts are mostly thin-section (3–12 mm) and require intensive bending/profiling. This profile is exactly where S700MC is strong: with its thermomechanically rolled structure, it offers superior cold forming, a smooth surface, and tight tolerances. In very thick main beams or heavily abraded tipper floors, it can be combined with S690QL or wear steel.
| Part | Recommended Grade | Expected Gain |
|---|---|---|
| Chassis profiles (thin section) | S700MC | Low tare → load increase |
| Tipper body structure | S700MC | Light body, easy bending |
| Thick main beam / low-bed floor | S690QL | High strength |
| Tipper wear floor | Hardox (combined) | Wear resistance |
Recommended grade: S700MC for thin-section and bending-intensive parts; S690QL for thick load-bearers. See our comparison page for S700MC vs S690QL.
Which Steel for Which Sector?
The typical grade preferences and main benefits of the sectors at a glance:
| Sector | Recommended Grade | Main Benefit |
|---|---|---|
| Cranes & Lifting | S690QL | Light boom → long reach / high capacity |
| Mining & Heavy Machinery | S690QL (+ Hardox) | Strength + weight, combination on wear surface |
| Structural Steel & Bridges | S690QL | Thin section → low dead load, long span |
| Energy | S690QL (S700MC for thin parts) | Thick-section strength + fatigue resistance |
| Marine & Offshore | S690QL / S690QL1 | Low-temperature toughness + lightness |
| Trailers & Transport | S700MC (S690QL for thick beams) | Low tare → load increase within axle load |
Note: The table summarizes typical preferences; the final choice must be made on a project basis according to the part's thickness, forming needs, operating temperature, and the relevant standard/certification requirements.
Frequently Asked Questions About Industry Applications
How much weight does high-strength steel save?
When S690QL or S700MC is used instead of S355, the section required for the same design load can be reduced by approximately 30–40%. This means a significant weight reduction in the load-bearing structure, more payload, and lower transport cost.
The amount of gain varies with the load type, geometry, and especially the buckling/fatigue control. The gain is high in parts with simple stress control, but may be more limited in thin members where buckling is decisive.
Why is S690QL preferred in cranes?
A crane boom and chassis require both high strength and good toughness. With its quenched and tempered structure, S690QL offers balanced strength/toughness even in thick sections and provides a −40°C impact guarantee.
The result: a lighter boom means longer reach or higher lifting capacity with the same crane. In extremely cold conditions, S690QL1 (−60°C) can be considered.
Which steel is used in trailers?
Trailer and tipper chassis are usually thin-section (3–12 mm) and require intensive bending. In this range, thermomechanically rolled S700MC offers superior formability and a smooth surface.
S700MC lowers the trailer's empty weight (tare), allowing more load to be carried within axle-load limits. S690QL can be combined for thick main beams, and Hardox-type steel for worn tipper floors.
Should I choose S700MC or S690QL?
The decision depends on the part's characteristics:
- S700MC: If thin sections, intensive cold forming, and series production dominate (typically below 12–16 mm).
- S690QL: When thick sections, high toughness, and heavy load-bearers are required (8–120 mm range).
In short, S700MC stands out for trailers/profiles/bending, while S690QL stands out for cranes/bridges/thick load-bearers. See our S690QL vs S700MC page for a detailed comparison.
Let's Choose the Right Steel for Your Project Together
Cranes, mining, bridges, energy, marine, or trailers — whatever sector you are in, we offer delivery from our S690QL and S700MC stock, including cutting and bending. Get in touch with your project drawing.