--- title: "BM42 — High-speed steels" description: "BM42 in BS: material number 1.3247, also listed as HS2-9-1-8. It is a material in the category High-speed steels. 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Compare it to detect a real > content change; `generated` moves on every render and is not a change signal. BS · United Kingdom · 28 designations # BM42 BM42 is a designation in BS for the material held under material number 1.3247, also listed as HS2-9-1-8. It is a material in the category High-speed steels. We list 28 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, AFNOR, UNE, ISO, JIS, GB, GOST, UNI, PN, MSZ, BDS and KS. - [*Material no.* **1.3247**](/materials/material-no/1.3247 "Material no.: 1.3247") - [*Category* **High-speed steels · 59 grades**](/categories/high-speed-steels "Category: High-speed steels · 59 grades") - *Designations* **28** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=720669a9-3a8a-48c9-ba7a-09301320117b&designation=0243f614-7042-4da6-b4c6-814dbb8e4134 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/bm42.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN HS2-9-1-8 This grade’s own name](/materials/din-en/hs2-9-1-8 "DIN / EN HS2-9-1-8") - [UNS T11342 This grade’s own name](/materials/uns/t11342 "UNS T11342") - [AISI / SAE M42 This grade’s own name](/materials/aisi-sae/m42 "AISI / SAE M42") - [KS SKH59 This grade’s own name](/materials/ks/skh59 "KS SKH59") ## About High-speed steels High-speed steels are alloyed tool steels designed to retain hardness and cutting ability when tools heat up during high-speed machining. Their hot hardness and wear resistance make them suitable for cutting tools such as drills, milling cutters, taps and broaches. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 28 designations · 15 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 Withdrawn designation no longer current — a separate column from the two above, so a name can be same grade and withdrawn at once.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 - [HS2-9-1-8 This grade’s own name](/materials/din-en/hs2-9-1-8 "DIN / EN HS2-9-1-8") - [S 2-10-1-8 This grade’s own name Withdrawn](/materials/din-en/s-2-10-1-8 "DIN / EN S 2-10-1-8") UNS United States · 2 - [T11342 This grade’s own name](/materials/uns/t11342 "UNS T11342") - [T11342 / T11842 Indicative](/materials/uns/t11342-t11842 "UNS T11342 / T11842") AISI / SAE United States · 6 - [M30 Indicative](/materials/aisi-sae/m30 "AISI / SAE M30") - [M42 This grade’s own name](/materials/aisi-sae/m42 "AISI / SAE M42") - [M47 Indicative](/materials/aisi-sae/m47 "AISI / SAE M47") - [T11330 Indicative](/materials/aisi-sae/t11330 "AISI / SAE T11330") - [T11342 Indicative](/materials/uns/t11342 "AISI / SAE T11342") - [T11347 Indicative](/materials/aisi-sae/t11347 "AISI / SAE T11347") BS United Kingdom · 2 - **BM42 Indicative** - [BT42 Indicative](/materials/bs/bt42 "BS BT42") AFNOR France · 2 - [HS2-9-1-8 Indicative](/materials/din-en/hs2-9-1-8 "AFNOR HS2-9-1-8") - [Z110DKCWV09-08-04-02-01 Indicative](/materials/afnor/z110dkcwv09-08-04-02-01 "AFNOR Z110DKCWV09-08-04-02-01") UNE Spain · 2 - [7-4-2-5 Indicative](/materials/une/7-4-2-5 "UNE 7-4-2-5") - [F.5615 Indicative](/materials/une/f-5615 "UNE F.5615") ISO International · 1 - [HS2-9-1-8 Indicative](/materials/din-en/hs2-9-1-8 "ISO HS2-9-1-8") JIS Japan · 1 - [SKH59 Indicative](/materials/ks/skh59 "JIS SKH59") GB China · 1 - [W2Mo9Cr4VCo8 Indicative](/materials/gb/w2mo9cr4vco8 "GB W2Mo9Cr4VCo8") GOST Russia / CIS · 4 - [R2AM9K Indicative](/materials/gost/r2am9k "GOST R2AM9K") - [R2M10K8 Indicative](/materials/gost/r2m10k8 "GOST R2M10K8") - [R2АM9K5 Indicative](/materials/gost/r2am9k5 "GOST R2АM9K5") - [Р2АМ9К5 Indicative](/materials/gost/r2am9k5 "GOST Р2АМ9К5") UNI Italy · 1 - [HS2-9-1-8 Indicative](/materials/din-en/hs2-9-1-8 "UNI HS2-9-1-8") PN Poland · 1 - [SK8M Indicative](/materials/pn/sk8m "PN SK8M") MSZ Hungary · 1 - [R11 Indicative](/materials/msz/r11 "MSZ R11") BDS Bulgaria · 1 - [R2M8K5F2 Indicative](/materials/bds/r2m8k5f2 "BDS R2M8K5F2") KS South Korea · 1 - [SKH59 This grade’s own name](/materials/ks/skh59 "KS SKH59") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 10 elements on file · weight % What this alloy is Fe Mo Co Cr Iron — the balance, never listed by a standard — 73.6 % Mo — 9.5 % Co — 8 % Cr — 4 % Traces & impurities · 4.9 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 1.05–1.15 | | Si | ≤ 0.7 | | Mn | ≤ 0.4 | | P | 0.03 | | S | 0.03 | | Cr | 3.5–4.5 | | Mo | 9–10 — Unusual | | V | 0.9–1.3 | | W | 1.2–1.9 | | Co | 7.5–8.5 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Vanadium Tungsten Cobalt 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 | 1,05-1,15 | 1.050 | 1.150 | Range | | Si | ≤0,70 | — | 0.700 | Max | | P | 0,03 | 0.030 | 0.030 | Exact | | S | 0,03 | 0.030 | 0.030 | Exact | | V | 0,90-1,30 | 0.900 | 1.300 | Range | | Cr | 3,50-4,50 | 3.500 | 4.500 | Range | | Mn | ≤0,40 | — | 0.400 | Max | | Co | 7,50-8,50 | 7.500 | 8.500 | Range | | Mo | 9,00-10,0 | 9.000 | 10.000 | Range | | W | 1,20-1,90 | 1.200 | 1.900 | 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. ## Physical & mechanical properties Density 8,01 g/cm³ Exact 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 · 3 values By delivery state**no delivery state stated** source `steeljis` | Delivery state | HB | |---|---| | Annealed | 277 | By delivery state**Soft annealed** source `steelnumber` | Delivery state | HB | |---|---| | Soft annealed | 277 | By delivery state**no delivery state stated** source `splav` | Delivery state | HB | |---|---| | (annealing) , GOST 19265-73 | 285 | 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 **GB /T 9943-2025** In this order Test specimen 1. Preheating 800–900 °C 2. Quenching 1170–1190 °C Quenchant Oil, Salt bath or Nitrogen 3. Tempering 550 °C Supply condition - Annealing Supply condition - Quenching and Tempering Test specimen - 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/azhlNWIxMTQ4NTk_ "Source: www.caishuku.com") ## Similar grades — and why Selection rule, stated so you can disagree with it: same number class 1.3, a shared category, and a published range for Mo / Co 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. [HS2-9-2-8 1.3249 Mo 8,00-9,20 · Co 7,75-8,75 - ΔMo 0.90 - ΔCo 0.25 - 9 designations](/materials/din-en/hs2-9-2-8 "HS2-9-2-8") ## 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=720669a9-3a8a-48c9-ba7a-09301320117b&designation=0243f614-7042-4da6-b4c6-814dbb8e4134 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/bm42.pdf "Datasheet as PDF")