Carbon & alloy steel · EN 10083-2
C45 (1045) Q&T
Also known as: C45 Q&T, 1045 QT
Overview
C45 / 1045 quenched and tempered for higher yield and hardness — preferred when normalized strength is insufficient.
Typical supply: Bars and forgings, heat-treated
Mechanical Properties
Thermal Properties
For temperature derating, open Temperature Properties.
Physical Properties
Typical supply: Bars and forgings, heat-treated
Density typically ~7800–7850 kg/m³. Bar and forging forms dominate machine design.
Applications
- Higher-duty shafts
- Bolted machine elements
- Wear-resistant pins
- Hydraulic cylinder rods (selected)
Advantages
- Higher strength and hardenability than mild structural steel
- Responds well to quench and temper for tailored properties
- Good fatigue performance when heat-treated correctly
Limitations
- Often needs heat treatment to reach published strengths
- Weldability may require preheat / post-weld heat treatment
- Corrosion resistance similar to carbon steel unless coated
Standards
- EN 10083-2 — Quenched and tempered steels — non-alloy
Equivalent Materials
Electrical Properties
Chemical Composition
| Element | Min wt% | Max wt% | Typical wt% |
|---|---|---|---|
| C | 0.42 | 0.5 | 0.45 |
| Si | — | 0.4 | — |
| Mn | 0.5 | 0.8 | 0.65 |
| P | — | 0.045 | — |
| S | — | 0.045 | — |
Typical / limit values for reference selection only — verify against mill certs for certified work.
Machinability
Harder to machine after QT; rough machine before heat treatment when possible.
Cost
Similar base metal cost to normalized plus heat-treat premium.
Corrosion
Same as carbon steel; temper colors do not provide corrosion protection.
- Oil-lubricated machineryfair
- Outdoor uncoatedpoor
For allowance / life screening, open Corrosion Allowance.