M1

Data verified

M1 is a molybdenum high-speed steel with the tungsten mostly replaced by about 8.7% molybdenum, making it tougher than T1 at equal hardness. It was developed for drills and taps where T-series steels chipped.

Hardness62–65 HRC
DIN— (HS9-2-1 family)
AISIM1
JISSKH55 (near)
CategoryTool Steel

Chemical composition

ElementContent (%)
C0.78–0.88
Si≤0.50
Mn≤0.40
Cr3.50–4.00
Mo8.20–9.20
W1.40–2.10
V1.00–1.35

Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.

Properties

Delivery conditionAnnealed
Hardness (hardened)62–65 HRC
Density7.90 g/cm³
Red hardnessGood

Heat treatment

Preheat 730–845 °C; harden 1175–1220 °C salt/oil/air; triple temper 540–595 °C.

Equivalent grades

StandardDesignation
din— (HS9-2-1 family)
aisiM1
jisSKH55 (near)
gbW2Mo9Cr4V (near)

Compare side by side: M1 vs M2 · M1 vs M7

Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.

Applications & Processing

Applications: Twist drills, taps, reamers, milling cutters, punches.

Processing: Slightly more decarburization-sensitive than T1 — salt bath or vacuum hardening preferred.

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Source: ASTM A600 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.