--- title: "STS631J1 — composition, equivalents and standards" description: "STS631J1: 1 equivalent designations across 1 standards, with the recorded chemical composition shown next to the source text." canonical: https://steelequivalents.com/materials/ks/sts631j1 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/ks/sts631j1.md cs: https://steelequivalents.com/cs/materiály/ks/sts631j1.md de: https://steelequivalents.com/de/werkstoffe/ks/sts631j1.md es: https://steelequivalents.com/es/materiales/ks/sts631j1.md fr: https://steelequivalents.com/fr/matériaux/ks/sts631j1.md hu: https://steelequivalents.com/hu/anyagok/ks/sts631j1.md it: https://steelequivalents.com/it/materiali/ks/sts631j1.md nl: https://steelequivalents.com/nl/materialen/ks/sts631j1.md pl: https://steelequivalents.com/pl/materiały/ks/sts631j1.md pt: https://steelequivalents.com/pt/materiais/ks/sts631j1.md ru: https://steelequivalents.com/ru/материалы/ks/sts631j1.md tr: https://steelequivalents.com/tr/malzemeler/ks/sts631j1.md zh: https://steelequivalents.com/zh/材料/ks/sts631j1.md ja: https://steelequivalents.com/ja/材料/ks/sts631j1.md ar: https://steelequivalents.com/ar/المواد/ks/sts631j1.md ko: https://steelequivalents.com/ko/재료/ks/sts631j1.md pt-br: https://steelequivalents.com/pt-br/materiais/ks/sts631j1.md hi: https://steelequivalents.com/hi/सामग्री/ks/sts631j1.md content_hash: sha256:eb8cb72dc03eca3fc121fd5418d1a58eeb703d75fa39ab81acf616c4893a8349 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/sts631j1 > Canonical URL: https://steelequivalents.com/materials/ks/sts631j1 > 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 # STS631J1 STS631J1 is a grade designated under KS. Its recorded composition includes C ≤ 0.09%, Al 0.75–1.5%, Si ≤ 1%, Cr 16–18% and Ni 7–8.5%. No cross-standard equivalents are recorded for this grade yet. - *Designations* **1** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=c74a019b-f10f-4e4b-b154-0cae74a73123&designation=3ad55162-a20a-4809-8b1b-ad57fc4a0e6d "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/ks/sts631j1.pdf "Datasheet as PDF") ## Chemical composition 8 elements on file · weight % What this alloy is Fe Cr Ni Al Iron — the balance, never listed by a standard — 72 % Cr — 17 % Ni — 7.8 % Al — 1.1 % Traces & impurities · 2.2 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | ≤ 0.09 | | Si | ≤ 1 | | Mn | ≤ 1 | | P | ≤ 0.04 | | S | ≤ 0.03 | | Cr | 16–18 | | Ni | 7–8.5 | | Al | 0.75–1.5 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Nickel Aluminium 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 | max 0.09 | — | 0.090 | Max | | Al | 0.75 - 1.5 | 0.750 | 1.500 | Range | | Si | max 1 | — | 1.000 | Max | | P | max 0.04 | — | 0.040 | Max | | S | max 0.03 | — | 0.030 | Max | | Cr | 16 - 18 | 16.000 | 18.000 | Range | | Mn | max 1 | — | 1.000 | Max | | Ni | 7 - 8.5 | 7.000 | 8.500 | Range | 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=c74a019b-f10f-4e4b-b154-0cae74a73123&designation=3ad55162-a20a-4809-8b1b-ad57fc4a0e6d "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/ks/sts631j1.pdf "Datasheet as PDF")