--- title: "STS420J1FB — composition, equivalents and standards" description: "STS420J1FB: 1 equivalent designations across 1 standards, with the recorded chemical composition shown next to the source text." canonical: https://steelequivalents.com/materials/ks/sts420j1fb language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/ks/sts420j1fb.md cs: https://steelequivalents.com/cs/materiály/ks/sts420j1fb.md de: https://steelequivalents.com/de/werkstoffe/ks/sts420j1fb.md es: https://steelequivalents.com/es/materiales/ks/sts420j1fb.md fr: https://steelequivalents.com/fr/matériaux/ks/sts420j1fb.md hu: https://steelequivalents.com/hu/anyagok/ks/sts420j1fb.md it: https://steelequivalents.com/it/materiali/ks/sts420j1fb.md nl: https://steelequivalents.com/nl/materialen/ks/sts420j1fb.md pl: https://steelequivalents.com/pl/materiały/ks/sts420j1fb.md pt: https://steelequivalents.com/pt/materiais/ks/sts420j1fb.md ru: https://steelequivalents.com/ru/материалы/ks/sts420j1fb.md tr: https://steelequivalents.com/tr/malzemeler/ks/sts420j1fb.md zh: https://steelequivalents.com/zh/材料/ks/sts420j1fb.md ja: https://steelequivalents.com/ja/材料/ks/sts420j1fb.md ar: https://steelequivalents.com/ar/المواد/ks/sts420j1fb.md ko: https://steelequivalents.com/ko/재료/ks/sts420j1fb.md pt-br: https://steelequivalents.com/pt-br/materiais/ks/sts420j1fb.md hi: https://steelequivalents.com/hi/सामग्री/ks/sts420j1fb.md content_hash: sha256:412c59a9baa044f0cafd8fcb270add5f8a363f37424e1e7b9f8c4153e340087f 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/ks/sts420j1fb > Canonical URL: https://steelequivalents.com/materials/ks/sts420j1fb > 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. KS · South Korea · 1 designation # STS420J1FB STS420J1FB is a grade designated under KS. Its recorded composition includes C 0.16–0.25%, Si ≤ 1%, Cr 12–14%, Mn ≤ 1% and Ni ≤ 0.6%. No cross-standard equivalents are recorded for this grade yet. - *Designations* **1** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=24334e81-979c-40d7-8708-ab853108df5f&designation=ee13ea9e-a329-4e38-8c91-7636057128eb "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/ks/sts420j1fb.pdf "Datasheet as PDF") ## Chemical composition 7 elements on file · weight % What this alloy is Fe Cr Si Mn Iron — the balance, never listed by a standard — 84.1 % Cr — 13 % Si — 1 % Mn — 1 % Traces & impurities · 0.9 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.16–0.25 | | Si | ≤ 1 | | Mn | ≤ 1 | | P | ≤ 0.04 | | S | ≤ 0.03 | | Cr | 12–14 | | Ni | ≤ 0.6 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Nickel 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 | 0.16 - 0.25 | 0.160 | 0.250 | Range | | Si | max 1 | — | 1.000 | Max | | P | max 0.04 | — | 0.040 | Max | | S | max 0.03 | — | 0.030 | Max | | Cr | 12 - 14 | 12.000 | 14.000 | Range | | Mn | max 1 | — | 1.000 | Max | | Ni | max 0.6 | — | 0.600 | 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: 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. ## 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=24334e81-979c-40d7-8708-ab853108df5f&designation=ee13ea9e-a329-4e38-8c91-7636057128eb "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/ks/sts420j1fb.pdf "Datasheet as PDF")