--- title: "ст.18ХГ — Case hardening steels" description: "ст.18ХГ in GOST: material number 1.7131, also listed as 16MnCr5. Category: Case hardening steels. Designations recorded for this grade: 78." canonical: https://steelequivalents.com/materials/gost/st-18khg language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/gost/st-18khg.md cs: https://steelequivalents.com/cs/materiály/gost/st-18khg.md de: https://steelequivalents.com/de/werkstoffe/gost/st-18khg.md es: https://steelequivalents.com/es/materiales/gost/st-18khg.md fr: https://steelequivalents.com/fr/matériaux/gost/st-18khg.md hu: https://steelequivalents.com/hu/anyagok/gost/st-18khg.md it: https://steelequivalents.com/it/materiali/gost/st-18khg.md nl: https://steelequivalents.com/nl/materialen/gost/st-18khg.md pl: https://steelequivalents.com/pl/materiały/gost/st-18khg.md pt: https://steelequivalents.com/pt/materiais/gost/st-18khg.md ru: https://steelequivalents.com/ru/материалы/gost/ст.18хг.md tr: https://steelequivalents.com/tr/malzemeler/gost/st-18khg.md zh: https://steelequivalents.com/zh/材料/gost/st-18khg.md ja: https://steelequivalents.com/ja/材料/gost/st-18khg.md ar: https://steelequivalents.com/ar/المواد/gost/st-18khg.md ko: https://steelequivalents.com/ko/재료/gost/st-18khg.md pt-br: https://steelequivalents.com/pt-br/materiais/gost/st-18khg.md hi: https://steelequivalents.com/hi/सामग्री/gost/st-18khg.md content_hash: sha256:85e16542e0122d4cb4a65cddc75a3268ac8a15a77e044f30a20b089212211771 generated: 2026-09-22 --- > **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/st-18khg > Canonical URL: https://steelequivalents.com/materials/gost/st-18khg > 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 · 78 designations # ст.18ХГ ст.18ХГ is a designation in GOST for the material held under material number 1.7131, also listed as 16MnCr5. It is a material in the category Case hardening steels. We list 78 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, ASTM, BS, AFNOR, UNE, ISO, JIS, GB, GOST, UNI, SS, ČSN, STN, PN, COPANT, SRPS, MSZ, STAS, AS / NZS, BDS, NBN, SFS and KS. - [*Material no.* **1.7131**](/materials/material-no/1.7131 "Material no.: 1.7131") - [*Category* **Case hardening steels · 60 grades**](/categories/case-hardening-steels "Category: Case hardening steels · 60 grades") - *Designations* **78** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=cb3fa07a-3d5d-4eca-a660-4821162dc0fb&designation=934bb285-acc2-4419-8ef8-393fb716bc8b "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/gost/st-18khg.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN 16MnCr5 This grade’s own name](/materials/din-en/16mncr5 "DIN / EN 16MnCr5") - [UNS G51150 This grade’s own name · 6 grades on that route](/materials/uns/g51150 "UNS G51150") - [AISI / SAE 5115 This grade’s own name · 2 grades on that route](/materials/aisi-sae/5115 "AISI / SAE 5115") - [SS SIS 14 2127 This grade’s own name](/materials/ss/sis-14-2127 "SS SIS 14 2127") ## About Case hardening steels Case hardening steels are steels designed to develop a hard, wear-resistant surface while retaining a tough and ductile core. They are used for components such as gears, shafts and other machine parts exposed to contact wear and cyclic loading. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 78 designations · 25 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 · 2 - [1.7131 Indicative](/materials/material-no/1.7131 "DIN / EN 1.7131") - [16MnCr5 This grade’s own name](/materials/din-en/16mncr5 "DIN / EN 16MnCr5") UNS United States · 3 - [G51150 This grade’s own name](/materials/uns/g51150 "UNS G51150") - [G51170 This grade’s own name](/materials/uns/g51170 "UNS G51170") - [G51200 Indicative](/materials/uns/g51200 "UNS G51200") AISI / SAE United States · 7 - [5115 This grade’s own name](/materials/aisi-sae/5115 "AISI / SAE 5115") - [5117 This grade’s own name](/materials/aisi-sae/5117 "AISI / SAE 5117") - [5120 Indicative](/materials/aisi-sae/5120 "AISI / SAE 5120") - [G51150 Indicative](/materials/uns/g51150 "AISI / SAE G51150") - [G51200 Indicative](/materials/uns/g51200 "AISI / SAE G51200") - [H51200 Indicative](/materials/uns/h51200 "AISI / SAE H51200") - [SAE5115 Indicative](/materials/aisi-sae/sae5115 "AISI / SAE SAE5115") ASTM United States · 1 - [SA-29 Grade 5115 Indicative](/materials/astm/sa-29-grade-5115 "ASTM SA-29 Grade 5115") BS United Kingdom · 6 - [16MnCr5 Indicative](/materials/din-en/16mncr5 "BS 16MnCr5") - [20MnCr5 Indicative](/materials/din-en/20mncr5 "BS 20MnCr5") - [527M17 Indicative](/materials/bs/527m17 "BS 527M17") - [527M20 Indicative](/materials/bs/527m20 "BS 527M20") - [590H17 Indicative](/materials/bs/590h17 "BS 590H17") - [590M17 Indicative](/materials/bs/590m17 "BS 590M17") AFNOR France · 4 - [16MC4 Indicative](/materials/afnor/16mc4 "AFNOR 16MC4") - [16MC5 Indicative](/materials/afnor/16mc5 "AFNOR 16MC5") - [16MnCr5RR Indicative](/materials/afnor/16mncr5rr "AFNOR 16MnCr5RR") - [20MC5 Indicative](/materials/afnor/20mc5 "AFNOR 20MC5") UNE Spain · 5 - [16MnCr5 Indicative](/materials/din-en/16mncr5 "UNE 16MnCr5") - [20MnCr5 Indicative](/materials/din-en/20mncr5 "UNE 20MnCr5") - [F.1515 Indicative](/materials/une/f-1515 "UNE F.1515") - [F.1515-16MnCr5 Indicative](/materials/une/f-1515-16mncr5 "UNE F.1515-16MnCr5") - [F.1516 Indicative](/materials/une/f-1516 "UNE F.1516") ISO International · 5 - [16MnCr5 Indicative](/materials/din-en/16mncr5 "ISO 16MnCr5") - [16MnCrS5 Indicative](/materials/din-en/16mncrs5 "ISO 16MnCrS5") - [20MnCr5 Indicative](/materials/din-en/20mncr5 "ISO 20MnCr5") - [20MnCrS5 Indicative](/materials/din-en/20mncrs5 "ISO 20MnCrS5") - [21MnCr5 Indicative](/materials/din-en/21mncr5 "ISO 21MnCr5") JIS Japan · 2 - [SMnC420 Indicative](/materials/jis/smnc420 "JIS SMnC420") - [SMnC420H Indicative](/materials/jis/smnc420h "JIS SMnC420H") GB China · 5 - [15CrMn Indicative](/materials/gb/15crmn "GB 15CrMn") - [16MnCr Indicative](/materials/gb/16mncr "GB 16MnCr") - [18CrMn Indicative](/materials/gb/18crmn "GB 18CrMn") - [20CrMn Indicative](/materials/gb/20crmn "GB 20CrMn") - [20CrMnTi Indicative](/materials/gb/20crmnti "GB 20CrMnTi") GOST Russia / CIS · 8 - [18ChG Indicative](/materials/bds/18chg "GOST 18ChG") - [18KHG Indicative](/materials/gost/18khg "GOST 18KHG") - [18KHGT Indicative](/materials/gost/18khgt "GOST 18KHGT") - [18YuA Indicative](/materials/gost/18yua "GOST 18YuA") - [18ХГ Indicative](/materials/gost/18khg "GOST 18ХГ") - [Sv-18KhGS Indicative](/materials/gost/sv-18khgs "GOST Sv-18KhGS") - [Sv-18KhMA Indicative](/materials/gost/sv-18khma "GOST Sv-18KhMA") - **ст.18ХГ Indicative** UNI Italy · 2 - [16MnCr5 Indicative](/materials/din-en/16mncr5 "UNI 16MnCr5") - [20MnCr5 Indicative](/materials/din-en/20mncr5 "UNI 20MnCr5") SS Sweden · 4 - [2127 Indicative](/materials/ss/2127 "SS 2127") - [2173 Indicative](/materials/ss/2173 "SS 2173") - [2511 Indicative](/materials/ss/2511 "SS 2511") - [SIS 14 2127 This grade’s own name](/materials/ss/sis-14-2127 "SS SIS 14 2127") ČSN Czechia · 4 - [14220 Indicative](/materials/csn/14220 "ČSN 14220") - [14221 Indicative](/materials/csn/14221 "ČSN 14221") - [14222 Indicative](/materials/csn/14222 "ČSN 14222") - [14223 Indicative](/materials/csn/14223 "ČSN 14223") STN Slovakia · 1 - [14 220 Indicative](/materials/csn/14220 "STN 14 220") PN Poland · 4 - [15HG Indicative](/materials/pn/15hg "PN 15HG") - [16HG Indicative](/materials/pn/16hg "PN 16HG") - [18HGT Indicative](/materials/pn/18hgt "PN 18HGT") - [20HG Indicative](/materials/pn/20hg "PN 20HG") COPANT Latin America · 1 - [5115 Indicative](/materials/aisi-sae/5115 "COPANT 5115") SRPS Serbia · 1 - [Č.4320 Indicative](/materials/srps/c-4320 "SRPS Č.4320") MSZ Hungary · 2 - [BC3 Indicative](/materials/msz/bc3 "MSZ BC3") - [BC3Z Indicative](/materials/msz/bc3z "MSZ BC3Z") STAS Romania · 4 - [17MnCr10 Indicative](/materials/stas/17mncr10 "STAS 17MnCr10") - [18MnCr10q Indicative](/materials/stas/18mncr10q "STAS 18MnCr10q") - [18MnCr11 Indicative](/materials/stas/18mncr11 "STAS 18MnCr11") - [20MnCr12 Indicative](/materials/stas/20mncr12 "STAS 20MnCr12") AS / NZS Australia / New Zealand · 2 - [5120 Indicative](/materials/aisi-sae/5120 "AS / NZS 5120") - [5120H Indicative](/materials/aisi-sae/5120h "AS / NZS 5120H") BDS Bulgaria · 2 - [16ChG Indicative](/materials/bds/16chg "BDS 16ChG") - [18ChG Indicative](/materials/bds/18chg "BDS 18ChG") NBN Belgium · 1 - [16MnCr5 Indicative](/materials/din-en/16mncr5 "NBN 16MnCr5") SFS Finland · 1 - [20MnCr5 Indicative](/materials/din-en/20mncr5 "SFS 20MnCr5") KS South Korea · 1 - [SMnC420H Indicative](/materials/jis/smnc420h "KS SMnC420H") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 6 elements on file · weight % What this alloy is Fe Mn Cr Si Iron — the balance, never listed by a standard — 97.3 % Mn — 1.2 % Cr — 1 % Si — 0.4 % Traces & impurities · 0.2 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.14–0.19 | | Si | ≤ 0.4 | | Mn | 1–1.3 | | P | 0.025 | | S | 0.035 | | Cr | 0.8–1.1 | Carbon Silicon Manganese Phosphorus Sulfur Chromium 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 | 0,14-0,19 | 0.140 | 0.190 | Range | | Si | ≤0,40 | — | 0.400 | Max | | P | 0,025 | 0.025 | 0.025 | Exact | | S | 0,035 | 0.035 | 0.035 | Exact | | Cr | 0,80-1,10 | 0.800 | 1.100 | Range | | Mn | 1,00-1,30 | 1.000 | 1.300 | 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: Ni, Mo. ## Physical & mechanical properties Density 7,76 g/cm³ Exact Transformation point Ac1 740 °C Exact Transformation point Ac3 825 °C Exact · Ac3(Acm) Transformation point Ar3 730 °C Exact · Ar3(Arcm) Transformation point Ar1 650 °C Exact Weldability readily weldable As published: without limitations. Flake sensitivity not susceptible As published: not predisposed Temper brittleness slightly susceptible As published: weakly predisposed 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 9 conditions · 57 values By dimension**Quenching 850°C, oil, Drawing 200°C, air** source `splav` | Dimension mm | Rm N/mm² | Re N/mm² | A5% | Z% | KCU kJ/m² | |---|---|---|---|---|---| | 5 | 1520 | 1320 | 12 | 50 | 720 | | 20 | 980 | 730 | 15 | 55 | 1130 | By delivery state**no delivery state stated** source `splav` | Delivery state | HB | |---|---| | (annealing) , GOST 4543-71 | 217 | | (cold-worked) , GOST 4543-71 | 229 | By delivery state**Soft annealed** source `steelnumber` | Delivery state | HB | HRB | HV | |---|---|---|---| | Soft annealed | 207 | 84 | 170 | By delivery state**Treated to hardness range** source `steelnumber` | Delivery state | HB | |---|---| | Treated to hardness range | 156 – 207 | By delivery state**Treated to ferrite-pearlite structure and hardness range** source `steelnumber` | Delivery state | HB | |---|---| | Treated to ferrite-pearlite structure and hardness range | 140 – 187 | By delivery state**Normalized** source `steelnumber` | Delivery state | HB | |---|---| | Normalized | 138 – 187 | By heat-treated condition**no delivery state stated** source `splav` | Heat-treated condition | Rm N/mm² | Re N/mm² | A5% | Z% | KCU kJ/m² | |---|---|---|---|---|---| | Bar, GOST 4543-71 | 980 | 885 | 9 | 50 | 780 | 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) | Specific heat capacity J/(kg·K) | |---|---|---|---|---|---| | 20 | 7.8 | 211 | — | 37 | — | | 100 | — | 205 | 10 | 38 | 495 | | 200 | — | 197 | 11.5 | 38 | 508 | | 300 | — | 191 | 12.3 | 37 | 525 | | 400 | — | 176 | 12.8 | 35 | 537 | | 500 | — | 168 | 13.3 | 34 | 567 | | 600 | — | 155 | 13.6 | 31 | 588 | | 700 | — | 136 | — | 30 | 626 | | 800 | — | 129 | — | 29 | 705 | At temperature**no delivery state stated** source `steelnumber` | Temperature °C | Rm N/mm² | |---|---| | 200 | 1000 | 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. ## Heat treatment Supply condition - Quenching and Tempering d=15 - Carburizing 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/azhlNWIxMTk3MjI_ "Source: www.caishuku.com") ## Similar grades — and why Selection rule, stated so you can disagree with it: same number class 1.7, a shared category, and a published range for Mn / Cr 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. [16MnCrS5 1.7139 Mn 1,00-1,30 · Cr 0,80-1,10 - ΔMn 0.00 - ΔCr 0.00 - 20 designations](/materials/din-en/16mncrs5 "16MnCrS5")[16MnCrB5 1.7160 Mn 1,00-1,30 · Cr 0,80-1,10 - ΔMn 0.00 - ΔCr 0.00 - 1 designations](/materials/din-en/16mncrb5 "16MnCrB5")[20MnCr5 1.7147 Mn 1,10-1,40 · Cr 1,00-1,30 - ΔMn 0.10 - ΔCr 0.20 - 45 designations](/materials/din-en/20mncr5 "20MnCr5")[20MnCrS5 1.7149 Mn 1,10-1,40 · Cr 1,00-1,30 - ΔMn 0.10 - ΔCr 0.20 - 17 designations](/materials/din-en/20mncrs5 "20MnCrS5")[1.7262 1.7262 Mn 0,80-1,10 · Cr 1,00-1,30 - ΔMn 0.20 - ΔCr 0.20 - 63 designations](/materials/material-no/1.7262 "1.7262")[20CrMo5 1.7264 Mn 0,90-1,20 · Cr 1,10-1,40 - ΔMn 0.10 - ΔCr 0.30 - 6 designations](/materials/din-en/20crmo5 "20CrMo5") ## 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=cb3fa07a-3d5d-4eca-a660-4821162dc0fb&designation=934bb285-acc2-4419-8ef8-393fb716bc8b "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/gost/st-18khg.pdf "Datasheet as PDF")