--- title: "TC90 — composition, equivalents and standards" description: "TC90 is a designation in ISO for the grade also listed as BW1A. We list 5 designations recorded for this grade, in the standards BS, ISO, JIS, GB and GOST." canonical: https://steelequivalents.com/materials/iso/tc90 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/iso/tc90.md cs: https://steelequivalents.com/cs/materiály/iso/tc90.md de: https://steelequivalents.com/de/werkstoffe/iso/tc90.md es: https://steelequivalents.com/es/materiales/iso/tc90.md fr: https://steelequivalents.com/fr/matériaux/iso/tc90.md hu: https://steelequivalents.com/hu/anyagok/iso/tc90.md it: https://steelequivalents.com/it/materiali/iso/tc90.md nl: https://steelequivalents.com/nl/materialen/iso/tc90.md pl: https://steelequivalents.com/pl/materiały/iso/tc90.md pt: https://steelequivalents.com/pt/materiais/iso/tc90.md ru: https://steelequivalents.com/ru/материалы/iso/tc90.md tr: https://steelequivalents.com/tr/malzemeler/iso/tc90.md zh: https://steelequivalents.com/zh/材料/iso/tc90.md ja: https://steelequivalents.com/ja/材料/iso/tc90.md ar: https://steelequivalents.com/ar/المواد/iso/tc90.md ko: https://steelequivalents.com/ko/재료/iso/tc90.md pt-br: https://steelequivalents.com/pt-br/materiais/iso/tc90.md hi: https://steelequivalents.com/hi/सामग्री/iso/tc90.md content_hash: sha256:8cf0eefc20241114777c7ca8ad370896e9e9903162f2969040c380aea2c02fcf generated: 2026-09-24 --- > **Machine-readable Markdown rendering.** This is a Markdown representation of a web page, > served for AI agents and crawlers as a token-efficient alternative to the full HTML. > Full interactive HTML version: https://steelequivalents.com/materials/iso/tc90 > Canonical URL: https://steelequivalents.com/materials/iso/tc90 > Available languages: en, cs, de, es, fr, hu, it, nl, pl, pt, ru, tr, zh, ja, ar, ko, pt-br, hi > Change detection: `content_hash` is the SHA-256 of this document's Markdown body — everything > below this block, whitespace-trimmed, excluding the front-matter. Compare it to detect a real > content change; `generated` moves on every render and is not a change signal. ISO · International · 5 designations # TC90 TC90 is a designation in ISO for the grade also listed as BW1A. We list 5 designations recorded for this grade, in the standards BS, ISO, JIS, GB and GOST. - *Designations* **5** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=7c4eced1-2780-43ef-834c-20327e4d3f22&designation=5cfdd6c6-8bbc-437f-9b89-dc580dbfed44 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/iso/tc90.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [GB T9 This grade’s own name](/materials/gb/t9 "GB T9") ## Also known as 5 designations · 5 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. BS United Kingdom · 1 - [BW1A Indicative](/materials/bs/bw1a "BS BW1A") ISO International · 1 - **TC90 Indicative** JIS Japan · 1 - [SK5 Indicative](/materials/jis/sk5 "JIS SK5") GB China · 1 - [T9 This grade’s own name](/materials/gb/t9 "GB T9") GOST Russia / CIS · 1 - [У9 Indicative](/materials/gost/u9 "GOST У9") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 7 elements on file · weight % What this alloy is Fe C Cr Si Iron — the balance, never listed by a standard — 98 % C — 0.9 % Cr — 0.3 % Si — 0.3 % Traces & impurities · 0.6 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.85–0.94 | | Si | 0.17–0.37 | | Mn | 0.1–0.4 | | P | ≤ 0.03 | | S | ≤ 0.025 | | Cr | ≤ 0.3 | | Cu | ≤ 0.25 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Copper 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 | 0.85-0.94 | 0.850 | 0.940 | Range | | Si | 0.17-0.37 | 0.170 | 0.370 | Range | | P | ≤0.03 | — | 0.030 | Max | | S | ≤0.025 | — | 0.025 | Max | | Cr | ≤0.3 | — | 0.300 | Max | | Mn | 0.1-0.4 | 0.100 | 0.400 | Range | | Cu | ≤0.25 | — | 0.250 | 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, Mo. ## Physical & mechanical properties 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 0 conditions · 0 values 1 further values are held for this grade under a condition the source did not name — a bound with no quantity attached. They are withheld rather than shown against a guessed condition. ## Heat treatment **GB /T 1299-2025** Single operation Test specimen - Quenching 760–780 °C Cooling Water Supply condition - Annealing Supply condition Conditions the standard permits on delivery. No temperature or medium is published for these, so no order and no alternation is implied. Source: [www.caishuku.com](https://www.caishuku.com/detail/azhlNWIxMzUxMDE_ "Source: www.caishuku.com") ## 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=7c4eced1-2780-43ef-834c-20327e4d3f22&designation=5cfdd6c6-8bbc-437f-9b89-dc580dbfed44 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/iso/tc90.pdf "Datasheet as PDF")