Can 1045 be through-hardened?

Only in thin sections — hardenability is limited. For thick sections needing Q&T strength, use 4140/42CrMo4.

1045

Data verified

1045 is the world’s most common medium-carbon steel — the default for shafts, hydraulic rods and plates that need more strength than mild steel, with optional induction hardening.

Hardness170–210 HB (normalized); 50+ HRC surface by induction

DIN1.0503 (C45)

AISI1045

JISS45C

CategoryCarbon Steel

Chemical composition

Element	Content (%)
C	0.43–0.50
Si	0.15–0.35 (typ.)
Mn	0.60–0.90
P	≤0.040
S	≤0.050

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

Properties

Tensile strength	570–700 MPa (normalized)
Hardness	170–210 HB (normalized); 50+ HRC surface by induction
Density	7.85 g/cm³

Heat treatment

Normalize 850 °C; quench 840 °C water/oil for small sections; induction hardening is the standard surface treatment.

Equivalent grades

Standard	Designation
din	1.0503 (C45)
aisi	1045
jis	S45C
gb	45

Compare side by side: 1045 vs S50C · 1045 vs SAE 1020

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

Applications & Processing

Applications: Shafts, hydraulic cylinder rods, gears (light), bolts, plates, seamless tube for machining.

Processing: Machines well normalized; welding needs preheat (150–250 °C) and controlled cooling.

FAQ

Can 1045 be through-hardened?: Only in thin sections — hardenability is limited. For thick sections needing Q&T strength, use 4140/42CrMo4.

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Source: SAE J403 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.