--- title: "43DD — Fine-grain structural steels" description: "43DD in BS: material number 1.0490, also listed as S275N. Category: Fine-grain structural steels. 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Compare it to detect a real > content change; `generated` moves on every render and is not a change signal. BS · United Kingdom · 12 designations # 43DD 43DD is a designation in BS for the material held under material number 1.0490, also listed as S275N. It is a material in the category Fine-grain structural steels. We list 12 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, JIS, UNI and KS. - [*Material no.* **1.0490**](/materials/material-no/1.0490 "Material no.: 1.0490") - [*Category* **Fine-grain structural steels · 50 grades**](/categories/fine-grain-structural-steels "Category: Fine-grain structural steels · 50 grades") - *Designations* **12** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=e47e6222-ae90-4483-889b-b6de2a622168&designation=e914bcd8-f36a-4d7e-8119-3c98bd435ee4 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/43dd.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN S275N This grade’s own name](/materials/din-en/s275n "DIN / EN S275N") - [UNS K03000 This grade’s own name · 4 grades on that route](/materials/uns/k03000 "UNS K03000") - [KS SM400B This grade’s own name](/materials/ks/sm400b "KS SM400B") ## About Fine-grain structural steels Fine-grain structural steel is a name for structural steels whose properties are particularly suitable for welding. They have a higher yield strength than comparable steels. Due to the negative influence of carbon on the weldability of a material, the maximum carbon content in fine-grained structural steels is less than 0.2%. These properties are achieved in steelmaking by the addition of oxygen and nitrogen-binding elements. The fine grain in the metallurgical structure is achieved by alloying elements whose nitrides and carbides only dissolve at higher temperatures. With the same composition, they are stronger and tougher than coarse-grained steels. Fine-grained structural steels are used above all in reinforced concrete structures such as bridges, in the construction of cranes, hydraulic cylinders or other welded structures due to their special welding suitability and in the offshore area. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 12 designations · 7 standards · nothing hidden This grade’s own name recorded in our sources as this grade’s own designation under that standard. Indicative taken from a published cross-reference table; a close match, not a guarantee of interchangeability. Verify against the mill certificate before ordering. Withdrawn designation no longer current — a separate column from the two above, so a name can be same grade and withdrawn at once. DIN / EN Europe · 5 - [1.0486 Indicative](/materials/material-no/1.0486 "DIN / EN 1.0486") - [A633A Indicative](/materials/din-en/a633a "DIN / EN A633A") - [FeE275KGN Indicative](/materials/uni/fee275kgn "DIN / EN FeE275KGN") - [S275N This grade’s own name](/materials/din-en/s275n "DIN / EN S275N") - [StE 285 This grade’s own name](/materials/din-en/ste-285 "DIN / EN StE 285") UNS United States · 1 - [K03000 This grade’s own name](/materials/uns/k03000 "UNS K03000") AISI / SAE United States · 2 - [A572Gr.42 Indicative](/materials/aisi-sae/a572gr-42 "AISI / SAE A572Gr.42") - [A633A Indicative](/materials/din-en/a633a "AISI / SAE A633A") BS United Kingdom · 1 - **43DD Indicative** JIS Japan · 1 - [SM400B Indicative](/materials/ks/sm400b "JIS SM400B") UNI Italy · 1 - [FeE275KGN Indicative](/materials/uni/fee275kgn "UNI FeE275KGN") KS South Korea · 1 - [SM400B This grade’s own name](/materials/ks/sm400b "KS SM400B") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 13 elements on file · weight % What this alloy is Fe Mn Cu Si Iron — the balance, never listed by a standard — 97.2 % Mn — 1 % Cu — 0.6 % Si — 0.4 % Traces & impurities · 0.8 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | ≤ 0.18 | | Si | ≤ 0.4 | | Mn | 0.5–1.5 | | P | 0.03 | | S | 0.025 | | Cr | ≤ 0.3 | | Mo | ≤ 0.1 | | V | ≤ 0.05 | | Cu | ≤ 0.55 | | Al | ≥ 0.02 | | Ti | ≤ 0.05 | | Nb | ≤ 0.05 | | N | 0.015 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Vanadium Copper Aluminium Titanium Niobium Nitrogen 0.01 % 0.1 % 1 % 10 % 100 % The scale is logarithmic, not the element’s raw share of the alloy — the only honest way to fit 0.01 % and 100 % in one picture, and it means every value here can be compared with every other. | Element | As published source text, verbatim | Min% by weight | Max% by weight | Bound | |---|---|---|---|---| | C | ≤0,18 | — | 0.180 | Max | | N | 0,015 | 0.015 | 0.015 | Exact | | Al | ≥0,02 | 0.020 | — | Min | | Si | ≤0,40 | — | 0.400 | Max | | P | 0,03 | 0.030 | 0.030 | Exact | | S | 0,025 | 0.025 | 0.025 | Exact | | Ti | ≤0,05 | — | 0.050 | Max | | V | ≤0,05 | — | 0.050 | Max | | Cr | ≤0,30 | — | 0.300 | Max | | Mn | 0,50-1,50 | 0.500 | 1.500 | Range | | Cu | ≤0,55 | — | 0.550 | Max | | Nb | ≤0,05 | — | 0.050 | Max | | Mo | ≤0,10 | — | 0.100 | Max | The published column is the source string byte-for-byte, decimal comma and all; Min and Max are the parsed bounds. Elements not listed have no value on file — they are omitted, never inferred. ## Predicted transformation temperatures Not enough recorded composition to predict a transformation temperature for this grade — missing: Ni. ## Physical & mechanical properties Density 7,85 g/cm³ Exact An absent property means we hold no value for it — it is left out rather than estimated, interpolated from a neighbouring grade, or filled from a handbook. It does not mean the property is undefined for the material. ## Properties by condition 3 conditions · 20 values By thickness**no delivery state stated** source `steelnumber` | Thickness mm | ReH N/mm² | A% | |---|---|---| | ≤ 16 | 275 | 24 | | 16 – 40 | 265 | 24 | | 40 – 63 | 255 | 24 | | 63 – 80 | 245 | 23 | | 80 – 100 | 235 | — | | 80 – 200 | — | 23 | | 100 – 150 | 225 | — | | 150 – 200 | 215 | — | | 200 – 250 | 205 | 23 | By thickness**Flat and long products** source `steelnumber` | Thickness mm | Rm N/mm² | |---|---| | ≤ 100 | 370 – 510 | | 100 – 200 | 350 – 480 | | 200 – 250 | 350 – 480 | By delivery state**no delivery state stated** source `steeljis` | Delivery state | Rm N/mm² | Re N/mm² | A% | |---|---|---|---| | Hot-rolled | 400 – 510 | 195 – 245 | 18 – 24 | Every figure holds only for the condition on its own row. Values are never merged across conditions or across sources, never averaged, and never interpolated between two rows. An em dash means no value on file — never zero. Figures are converted to the unit in the column header; the source’s own wording is kept and shown where the two differ. ## Similar grades — and why Selection rule, stated so you can disagree with it: same number class 1.0, a shared category, and a published range for Mn / Cu that overlaps this grade’s. These are neighbours in composition space — they are not equivalents, and none is claimed to be interchangeable with this grade. [S275NL 1.0491 Mn 0,50-1,50 · Cu ≤0,55 - ΔMn 0.00 - ΔCu 0.00 - 10 designations](/materials/din-en/s275nl "S275NL")[A662Gr.A 1.0488 Mn 0,60-1,50 · Cu ≤0,30 - ΔMn 0.05 - ΔCu 0.13 - 18 designations](/materials/din-en/a662gr-a "A662Gr.A")[P245GH 1.0352 Mn 0,50-1,30 · Cu ≤0,30 - ΔMn 0.10 - ΔCu 0.13 - 3 designations](/materials/din-en/p245gh "P245GH")[1.0486 1.0486 Mn 0,80-1,50 · Cu ≤0,30 - ΔMn 0.15 - ΔCu 0.13 - 18 designations](/materials/material-no/1.0486 "1.0486")[P275NH 1.0487 Mn 0,80-1,50 · Cu ≤0,30 - ΔMn 0.15 - ΔCu 0.13 - 10 designations](/materials/din-en/p275nh "P275NH")[S355NH 1.0545 Mn 0,90-1,65 · Cu ≤0,55 - ΔMn 0.27 - ΔCu 0.00 - 16 designations](/materials/din-en/s355nh "S355NH") ## Looking for this grade under another name? Search the catalogue by designation, material number or composition — every name on this page is itself a way in. [Search](/search "Steel grade search")[Inquiry](/inquiry?material=e47e6222-ae90-4483-889b-b6de2a622168&designation=e914bcd8-f36a-4d7e-8119-3c98bd435ee4 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/43dd.pdf "Datasheet as PDF")