The key terms from our materials database, in plain words. From every material page, the category line links straight to the matching entry.
← Back to the materials databaseThe stress up to which steel behaves elastically and springs back. Above it, permanent deformation begins — usually the most important value for design (given in MPa = N/mm²).
The maximum stress the material withstands in the tensile test before it necks and breaks. Standards give a window (min–max).
The percentage of elongation a specimen (80 mm gauge length) endures up to fracture — the measure of formability. Rule of thumb: the stronger, the less elongation.
The European numbering system (e.g. 1.0548 for HC340LA); the leading 1 denotes steel, aluminium begins with 3. More unambiguous than names, which can change with standard editions.
EN standards test automotive grades TRANSVERSE to the rolling direction, VDA 239-100 LONGITUDINAL. Longitudinal values come out lower — which is why EN and VDA grades correspond with a CLASS OFFSET: HC340LA (EN) ≈ CR300LA (VDA), not CR340LA. Whoever orders to VDA orders to VDA deliberately.
The joint material specification of the German automotive manufacturers for flat products. Designations begin with CR (cold rolled) or HR (hot rolled); coatings are appended (+Z).
Small additions of niobium, titanium or vanadium produce a very fine grain — high yield strength with good formability and weldability. Typical: structural parts, seats, reinforcements (HC260LA–HC500LA).
The grade gains additional yield strength during paint baking (approx. 170 °C, 20 min; ≥ 30–40 MPa). Form it soft first, then let it harden in the oven — ideal for outer-skin panels (HC180B, HC220B).
Decarburised to ~0.01 % carbon and stabilised with Ti/Nb — extremely deep-drawable. The higher-strength IF grades are the Y series (HC180Y / HC220Y / HC260Y; VDA: CR180IF / CR210IF / CR240IF).
Forming properties almost direction-independent (no “earing” during deep drawing). HC220I / HC260I / HC300I to EN 10268 — there is no VDA equivalent.
A microstructure of soft ferrite with embedded martensite — low yield strength during forming, high strength in the finished part, strongly work-hardening. Crash-relevant structural parts (HCT590X and others).
Even stronger multi-phase microstructures up to ~1200 MPa (CP: bendable, insensitive to edge cracking — profiles, sills; MS: highest strength — reinforcements, bumpers).
Retained austenite transforms into martensite under deformation — combining high strength with unusually good elongation.
A boron-manganese steel that is formed red-hot and quenched in the tool — finished parts up to ~1500 MPa tensile strength (A/B pillars). A mill grade, no EN standard; well-known brand names are Usibor (ArcelorMittal) or MBW (thyssenkrupp).
+Z hot-dip galvanised (standard corrosion protection), +ZE electrolytically galvanised (thinner, very even, good painting base), +ZF/GA galvannealed (zinc-iron, readily weldable), +ZM zinc-magnesium (better protection at a thinner coat), +AS aluminium-silicon (for press hardening).
See also: Reading designations
Supplier lists and our offer data often show several short codes next to the grade and the coating. Here is how they fit together:
CR4 · GI50/50 · U Grade CR4 · hot-dip galvanised, 50 g/m² per side · unexposed class U (VDA world) DX51D +Z100 M B O Grade DX51D · galvanised, 100 g/m² both sides total · minimized spangle · improved surface · oiled (EN world) See also: Coatings
Material that does not fully meet the mill's prime specification (e.g. surface, dimensional tolerance) — technically often perfectly usable and considerably cheaper. Exactly what makes a look at our current offers worthwhile.