**Brief Introduction of 37CrNi3A: Chemical Composition, Mechanical Properties, and Main Applications**
37CrNi3A is a high-performance alloy structural steel specified under the Chinese national standard. It is widely used in heavy-duty mechanical applications due to its excellent strength, toughness, and hardenability. The unified numerical code for this steel grade is **A42372**.
**Chemical Composition (wt%)**
- Carbon (C): 0.34 – 0.41%
- Silicon (Si): 0.17 – 0.37%
- Manganese (Mn): 0.30 – 0.60%
- Chromium (Cr): 1.20 – 1.60%
- Nickel (Ni): 3.00 – 3.50%
These elements contribute to the material’s high strength, wear resistance, and good fatigue performance.
**Mechanical Properties (Sample Size: 25mm)**
- **Heat Treatment:**
- Quenching temperature: 820°C, cooled with oil
- Tempering temperature: 500°C, cooled with water or oil
- **Mechanical Characteristics:**
- Tensile Strength (σb): ≥ 1130 MPa
- Yield Strength (σs): ≥ 980 MPa
- Elongation (δ5): ≥ 10%
- Reduction of Area (ψ): ≥ 50%
- Impact Toughness (Aku2): ≥ 47 J
- Brinell Hardness (HBS 100/3000): ≤ 269 (annealed or high-temperature tempered)
This steel exhibits **high toughness**, **excellent hardenability**, and can be fully hardened up to parts with a diameter of 150 mm when oil-cooled. It maintains stable creep resistance at 450°C and has good low-temperature impact resistance. However, it is prone to **second-type temper brittleness** when tempered between 450–550°C, and there is a risk of **white spot formation**. Therefore, **normalizing followed by high-temperature tempering** is recommended to improve machinability and reduce hardness.
**Main Features:**
- High strength and toughness
- Excellent hardenability
- Suitable for large cross-section components
- Good performance at elevated and low temperatures
- Requires proper heat treatment to avoid embrittlement
**Applications:**
37CrNi3A is commonly used in manufacturing **heavy-duty, impact-resistant components** such as rotor shafts, impellers, and critical fasteners. It is also suitable for **low-temperature impact parts**, **hot-forged**, and **hot-stamped components** where high mechanical reliability is required.
**Image Source:**
**Editor:** Hardware Business Network Information Center
**Source:** [http://news.chinawj.com.cn](http://news.chinawj.com.cn)
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*Word count: 536*
**Editor:** Hardware Business Network Information Center
**Source:** [http://news.chinawj.com.cn](http://news.chinawj.com.cn)
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