--- title: "4Х12Н8Г8МФБ — composition, equivalents and standards" description: "4Х12Н8Г8МФБ is a designation in GOST for the grade also listed as 37KH12N8G8MFB. Designations recorded for this grade: 4." canonical: https://steelequivalents.com/materials/gost/4kh12n8g8mfb language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/gost/4kh12n8g8mfb.md cs: https://steelequivalents.com/cs/materiály/gost/4kh12n8g8mfb.md de: https://steelequivalents.com/de/werkstoffe/gost/4kh12n8g8mfb.md es: https://steelequivalents.com/es/materiales/gost/4kh12n8g8mfb.md fr: https://steelequivalents.com/fr/matériaux/gost/4kh12n8g8mfb.md hu: https://steelequivalents.com/hu/anyagok/gost/4kh12n8g8mfb.md it: https://steelequivalents.com/it/materiali/gost/4kh12n8g8mfb.md nl: https://steelequivalents.com/nl/materialen/gost/4kh12n8g8mfb.md pl: https://steelequivalents.com/pl/materiały/gost/4kh12n8g8mfb.md pt: https://steelequivalents.com/pt/materiais/gost/4kh12n8g8mfb.md ru: https://steelequivalents.com/ru/материалы/gost/4х12н8г8мфб.md tr: https://steelequivalents.com/tr/malzemeler/gost/4kh12n8g8mfb.md zh: https://steelequivalents.com/zh/材料/gost/4kh12n8g8mfb.md ja: https://steelequivalents.com/ja/材料/gost/4kh12n8g8mfb.md ar: https://steelequivalents.com/ar/المواد/gost/4kh12n8g8mfb.md ko: https://steelequivalents.com/ko/재료/gost/4kh12n8g8mfb.md pt-br: https://steelequivalents.com/pt-br/materiais/gost/4kh12n8g8mfb.md hi: https://steelequivalents.com/hi/सामग्री/gost/4kh12n8g8mfb.md content_hash: sha256:e820e4db13cee0ac4ad94b770b5ec03ba41ca4eeeea48c46a64f64242215be7e 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/gost/4kh12n8g8mfb > Canonical URL: https://steelequivalents.com/materials/gost/4kh12n8g8mfb > 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. GOST · Russia / CIS · 4 designations # 4Х12Н8Г8МФБ 4Х12Н8Г8МФБ is a designation in GOST for the grade also listed as 37KH12N8G8MFB. We list 4 designations recorded for this grade, in the standards GOST. - *Designations* **4** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=e890a99c-b859-484f-a916-d0ebcf5f000c&designation=4952c7f0-1a9c-4969-a34c-6b9b67df7b27 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/gost/4kh12n8g8mfb.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [GOST 37KH12N8G8MFB This grade’s own name](/materials/gost/37kh12n8g8mfb "GOST 37KH12N8G8MFB") ## Also known as 4 designations · 1 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. GOST Russia / CIS · 4 - [37KH12N8G8MFB This grade’s own name](/materials/gost/37kh12n8g8mfb "GOST 37KH12N8G8MFB") - [37Х12Н8Г8МФБ Indicative](/materials/gost/37kh12n8g8mfb "GOST 37Х12Н8Г8МФБ") - **4Х12Н8Г8МФБ Indicative** - [ЭИ481 Indicative](/materials/gost/ei481 "GOST ЭИ481") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 11 elements on file · weight % What this alloy is Fe Cr Mn Ni Iron — the balance, never listed by a standard — 66.7 % Cr — 12.5 % Mn — 8.5 % Ni — 8 % Traces & impurities · 4.3 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.34–0.4 | | Si | 0.3–0.8 | | Mn | 7.5–9.5 — Unusual | | P | ≤ 0.035 | | S | ≤ 0.03 | | Cr | 11.5–13.5 | | Mo | 1.1–1.4 | | Ni | 7–9 | | V | 1.25–1.55 | | Cu | ≤ 0.3 | | Nb | 0.25–0.45 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Nickel Vanadium Copper Niobium 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 | 0.34 - 0.4 | 0.340 | 0.400 | Range | | Si | 0.3 - 0.8 | 0.300 | 0.800 | Range | | P | max 0.035 | — | 0.035 | Max | | S | max 0.03 | — | 0.030 | Max | | V | 1.25 - 1.55 | 1.250 | 1.550 | Range | | Cr | 11.5 - 13.5 | 11.500 | 13.500 | Range | | Mn | 7.5 - 9.5 | 7.500 | 9.500 | Range | | Ni | 7 - 9 | 7.000 | 9.000 | Range | | Cu | max 0.3 | — | 0.300 | Max | | Nb | 0.25 - 0.45 | 0.250 | 0.450 | Range | | Mo | 1.1 - 1.4 | 1.100 | 1.400 | 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 This grade's composition falls outside the published model's validated range (a low-alloy composition window), so no transformation temperature is predicted here. ## Physical & mechanical properties Weldability weldable with restrictions As published: limited weldability. 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 · 40 values By heat-treated condition**no delivery state stated** source `splav` | Heat-treated condition | Rm N/mm² | Re N/mm² | A5% | Z% | KCU kJ/m² | |---|---|---|---|---|---| | Heating 1140 - 1160°C, 1h,Cooling water, Ageing 660 - 790°C, 10 - 16h, air | 1000 | 600 | 20 | 25 | 350 | By delivery state**no delivery state stated** source `splav` | Delivery state | HB | |---|---| | 37KH12N8G8MFB ( 37Х12Н8Г8МФБ ) (annealing) , Bar GOST 18907 | 269 | At temperature**no delivery state stated** source `splav` | Temperature °C | Density g/cm³ | Elastic modulus GPa | Thermal expansion coefficient 10^-6/K | Thermal conductivity W/(m·K) | Electrical resistivity nΩ·m | |---|---|---|---|---|---| | 20 | 7.85 | 174 | — | — | 740 | | 100 | — | — | 15.9 | 17.2 | 850 | | 200 | — | 160 | 17.1 | 18.5 | 900 | | 300 | — | 150 | 18.2 | 19.7 | 950 | | 400 | — | 143 | 19.2 | 21.4 | 1010 | | 500 | — | 135 | 20.3 | 23 | 1100 | | 600 | — | 128 | 21.2 | 24.8 | 1150 | | 700 | — | 125 | 22.2 | 25.9 | 1200 | | 800 | — | — | 23.2 | 27.2 | — | | 900 | — | — | 24.2 | 29.3 | — | 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. ## 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=e890a99c-b859-484f-a916-d0ebcf5f000c&designation=4952c7f0-1a9c-4969-a34c-6b9b67df7b27 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/gost/4kh12n8g8mfb.pdf "Datasheet as PDF")