When you choose a new car or plan to repair the body, the question of the material it is made of often remains in the shadows. But in vain! From the fact what kind of steel is the car made of?, depend on its strength in an accident, corrosion resistance, weight and even the cost of insurance. Modern automakers use more than 200 different types of steel - from classic low-carbon to ultra-strong alloys with boron and aluminum.
In this article we will look at what types of steel are used in the automotive industry today, how they differ and how they affect the operation of the car. You'll find out why Toyota Corolla and Mercedes S-Class are made from different materials, even if both have a steel body, and how this affects safety and durability. And also, what nuances are important to consider when doing body repairs, so as not to run into problems with rust or deformation.
Spoiler: not all steel is created equal. For example, premium car bodies often contain up to 40% high-strength steel, while in budget models their share barely reaches 10%. This directly affects how the car behaves in an accident and how long it will last without corrosion.
1. Main types of steel in the automotive industry: classification and properties
Automotive steel is divided into several key categories, each of which plays a different role in the body structure. The main classification criteria are: strength, plasticity and corrosion resistance. Let's look at the main types:
- 🔹 Low carbon steel (
Mild Steel): the cheapest and most common. Used for non-critical panels (fenders, hood). Strength: 200–300 MPa. Easily deformed upon impact, but can be easily repaired. - 🔹 High strength steel (
HSS — High-Strength Steel): strength 300–700 MPa. It is used in the power frame of the body. Allows you to reduce the thickness of the metal without losing rigidity. - 🔹 Ultra high strength steel (
UHSS — Ultra-High-Strength Steel): strength 700–1500 MPa. Used in crumple zones to absorb energy during road accidents. Often doped with boron (boron steel). - 🔹 Dual phase steel (
DP — Dual Phase): combines soft and hard phases. Ideal for elements that must bend but not break (such as side members). - 🔹 TRIP steel (
TRIP — Transformation-Induced Plasticity): has the unique property of “self-strengthening” during deformation. Used in Volvo and BMW to improve passive safety.
Interesting fact: up to 10 different types of steel can be combined in the body of a modern car! For example, in Ford F-150 2023 uses aluminum panels and a steel frame made of UHSS, and in Tesla Model Y - steel coated with zinc-aluminum-magnesium alloy for corrosion protection.
⚠️ Attention: If you are planning welding work on the body, be sure to check the type of steel! Ultra High Strength Steels (UHSS) require special electrodes and welding modes. Conventional arc welding can weaken metal by 30–40%.
2. What kind of steel is used in budget and premium cars: comparison
The difference between steel in Lada Granta and Audi A8 is colossal - and it’s not just marketing. Premium car manufacturers invest in expensive alloys to reduce weight, improve safety and extend body life. The table below compares typical materials for different classes of machines:
| Car class | Main types of steel | Share of high-strength steels | Metal thickness, mm | Corrosion resistance |
|---|---|---|---|---|
| Budget (Lada, Datsun, Renault Logan) | Low carbon, HSS (up to 300 MPa) | 5–15% | 0.7–1.0 | Medium (zinc plating 5–7 microns) |
| Middle class (Toyota Corolla, VW Golf) | HSS (300–500 MPa), DP steel | 20–30% | 0.6–0.9 | Good (zinc plating 10–15 microns) |
| Premium (BMW 5 Series, Mercedes E-Class) | UHSS (700–1000 MPa), TRIP steel, boron alloys | 40–60% | 0.5–0.8 | Excellent (zinc-aluminum coating 20+ microns) |
| Sports/electric cars (Porsche 911, Tesla Model S) | UHSS (1000–1500 MPa), aluminum, composites | up to 80% | 0.4–0.7 | Premium (multilayer coatings) |
Why is this important to the owner? For example, in case of an accident the body Skoda Octavia with 30% high-strength steel, deforms predictably, protecting occupants, while Lada Vesta with low-carbon steel it can simply fold like an accordion. In addition, Repairing a UHSS body costs 2–3 times more due to the need for special equipment.
Another nuance: in premium cars it is often used hot stamped steel (hot stamping). It is heated to 900°C, stamped and quickly cooled - this increases the strength to 1500 MPa. This technology is used in Audi, Volvo and Jaguar to protect the interior during side impacts.
When buying a used car, check the thickness of the paintwork and metal with a thickness gauge. If the body is made of low-carbon steel with a thickness of less than 0.7 mm, the risk of corrosion increases by 2 times even with small chips.
3. How to determine what kind of steel your car is made of: practical tips
It is difficult to find out the exact composition of steel in your car without documentation, but there are several working methods:
- Study the technical documentation. Car manuals (especially premium brands) often indicate the types of steel used. For example, Volvo publishes share data
UHSSin the back. - Look at the part markings. Steel markings are sometimes applied to internal body panels (under the hood, in the trunk):
- 🔧
DC01,DC04— low-carbon steel for cold stamping. - 🔧
HCT600X— high-strength steel with a strength of 600 MPa. - 🔧
DP800- two-phase steel.
- 🔧
HSS from UHSS.If you are planning a renovation, be sure to check the type of steel with an authorized dealer. For example, when replacing a spar in Ford Focus 2020 may be required DP600, and not ordinary low-carbon steel - otherwise the strength of the body will be reduced by 40%.
☑️ What to check before body repair
4. Pros and cons of steel bodies: fair comparison with aluminum and carbon fiber
Steel remains the most popular material for bodies (about 70% of the market), but it has competitors - aluminum, magnesium and carbon fiber. Let's look at the strengths and weaknesses:
Advantages of steel:
- ✅ Low cost. A steel body is 30–50% cheaper than an aluminum one.
- ✅ Ease of repair. Welding and straightening steel is cheaper than repairing carbon fiber.
- ✅ High tensile strength. Modern
UHSSThey are not inferior to aluminum in terms of rigidity with a smaller thickness. - ✅ Good sound insulation. Steel dampens noise better than aluminum.
Disadvantages of steel:
- ❌ Weight. Even
UHSS20–30% heavier than aluminum. This affects fuel consumption and dynamics. - ❌ Corrosion. Without high-quality galvanizing, steel rusts 3–5 times faster than aluminum.
- ❌ Difficulty of stamping. High-strength steels require powerful presses, which increases production costs.
For comparison: body Audi A8 It is made of 40% aluminum, which reduces its weight by 240 kg compared to the steel version. But repairing such a body costs 2–3 times more. And carbon fiber (as in BMW i3) is even easier, but its repair is often impossible - only replacing the panel.
⚠️ Attention: If you operate a car in regions with salty roads (for example, Moscow, St. Petersburg), a steel body without additional anti-corrosion treatment will last no more than 5–7 years. Aluminum and magnesium corrode more slowly under such conditions, but require special detergents.
5. Steel corrosion: how to protect the body and what to do if rust has already appeared
The main enemy of a steel body is corrosion. It starts with microscopic damage to the paintwork and after 2-3 years can lead to through holes. Particularly vulnerable:
- 🚗 Thresholds and wheel arches — constantly in contact with moisture and salt.
- 🚗 Bottom — susceptible to sandblast wear and chemical reagents.
- 🚗 Panel joints - if the factory anti-corrosion treatment is of poor quality.
How to protect a steel body:
- Regular washing. Remove salt and dirt at least once every 2 weeks in winter. Use a touchless car wash to avoid damaging the paintwork.
- Anti-corrosion treatment. Best practices:
- 🔹 Movil — for hidden cavities (cost: 3–5 thousand rubles).
- 🔹 Liquid plastic — for the bottom (lasts 3–5 years).
- 🔹 Galvanizing - the most reliable, but expensive (from 20 thousand rubles).
If rust has already appeared:
- 🛠️ Local outbreaks (up to 2 cm): clean with sandpaper, treat with a rust converter (Tsinkar), prime and paint.
- 🛠️ Through corrosion: only cutting out the area and welding the patch. Self-repair is not recommended - a welding machine and experience are required.
Why is “cosmetic” rust putty dangerous?
Many car owners simply putty on rusty areas without removing the source of corrosion. This leads to the fact that rust continues to spread under the putty, and after 1-2 years the metal will rust through. Proper repair includes complete removal of corrosion down to the “living” metal, treatment with anti-corrosion agent and only then putty.
6. Features of repairing bodies made of high-strength steel: what not to do
If your car was produced after 2015, most likely, its body contains elements from HSS or UHSS. Repair of such steels has critical nuances:
- 🔥 Welding. Conventional arc welding weakens
UHSSby 30–40%. Special electrodes are needed (for example, ESAB OK Autrod 13.21) and welding modes with controlled heat input. - 🔨 Straightening. High-strength steels “do not like” heating - this changes their structure. Use cold straightening with hydraulic tools.
- 🔧 Replacing panels. In some models (for example, Volvo XC90) spars are made of
boron steelby hot stamping method. They cannot be repaired - only complete replacement.
Case study: after an accident Skoda Kodiaq 2022 with damage to the rear side member from DP800 The technician at a regular service center tried to straighten it with heat. The result is that the metal lost its strength, and after a month the spar cracked. The right solution: replacing the part using spot welding and adhesive joints.
⚠️ Attention: If your car uses adhesive connection of panels (technology Bonding, used in Jaguar Land Rover and Porsche), under no circumstances disassemble the body without special equipment! Improper dismantling can disrupt the geometry by 0.5–1 mm, which will lead to uneven tire wear and poor handling.
When repairing high-strength steel bodywork, be sure to use the manufacturer's specifications regarding steel types and joining methods. For example, in Mercedes-Benz for UHSS it is prescribed to use riveting instead of welding in 60% of cases.
7. The future of steel bodies: what technologies to expect in 2026–2030
Automakers are actively looking for alternatives to traditional steel, but it remains the main material for now. However, its production technologies are changing:
- 🚀 3rd generation steel. New alloys (eg
Q&P — Quenching & Partitioning) combine strengthUHSS(1200–1500 MPa) and ductility of low-carbon steel. Developed for electric vehicles. - 🚀 Hybrid bodies. A combination of steel, aluminum and carbon fiber (for example, in BMW i4). Steel is used for the load-bearing frame, and lightweight materials are used for the panels.
- 🚀 Self-healing coatings. Nanoparticles of zinc and graphene in paintwork “heal” microcracks, preventing corrosion. Technology is being tested Nissan and Hyundai.
- 🚀 Eco-friendly steel. Steel production is responsible for 7% of global CO₂ emissions. Companies like SSAB They are developing “green” steel, produced using hydrogen instead of coal.
Interesting trend: in 2026 Tesla started using graded strength steel — one part combines areas with different hardnesses. For example, in the front bumper Tesla Cybertruck the outer layer is hard (to protect against impacts), and the inner layer is plastic (to absorb energy).
What does this mean for owners? In the next 5–10 years, steel will not disappear, but its properties will change dramatically. Cars will become lighter, safer and more environmentally friendly, but their repair will require even more highly qualified craftsmen.
Frequently Asked Questions
Is it possible to weld high-strength steel with a conventional welding machine?
No. High strength steels (HSS, UHSS) require special electrodes (for example, low hydrogen content) and controlled thermal conditions. Conventional welding weakens the metal by 30–40%, which is critical for safety. For boron steels (strength 1500 MPa) laser welding or riveting is often used.
What kind of steel is used in the Lada Vesta body?
B Lada Vesta (2023) predominantly low-carbon steel is used (DC01, DC04) thickness 0.7–0.9 mm. Share of high-strength steels (HSS) does not exceed 15% (mainly in the power frame). For comparison: in Toyota Camry same year share HSS/UHSS reaches 40%. Anti-corrosion coating - galvanizing 7–10 microns (medium level of protection).
Why do premium cars use boron steel?
Boron steel (e.g. 22MnB5) after hot stamping, it acquires strength up to 1500 MPa while maintaining ductility. This allows body elements to be made thinner and lighter without sacrificing safety. This steel is used in Volvo, BMW and Mercedes to protect the interior during side impacts. The downside is that it cannot be repaired using traditional methods, only replacement of the part.
Which metal is better for the body: steel or aluminum?
It depends on priorities:
- 🔹 Steel cheaper to repair, dampens vibrations and noise better, but is heavier and susceptible to corrosion.
- 🔹 Aluminum 30–40% lighter, does not rust, but repairs cost 2–3 times more, and the body is less rigid when impacted.
The best option is a hybrid body (steel frame + aluminum panels), as in Audi A8 or Jaguar XE.
Is it possible to restore a rusted body using high-strength steel?
Theoretically yes, but with reservations:
- If the rust is superficial - stripping, converter (for example, Tsinkar), primer and painting.
- If there is through corrosion - only cutting out the area and welding a patch from the same grade of steel. For
UHSSTig welding or riveting will be required.
Important: after repairing high-strength steel, be sure to check the body geometry on a stand. Even a minimal displacement (0.3–0.5 mm) can disrupt the operation of safety systems (for example, the deployment of airbags).