1Cr13 stainless steel is a martensitic stainless steel with low carbon content, belonging to the Cr13 series. It is widely used in various industrial and daily scenarios due to its good comprehensive performance, including moderate corrosion resistance, excellent toughness, and processability. Below is a detailed introduction:
1. Chemical Composition
The main chemical components (by weight percentage) of 1Cr13 are as follows:
Chromium (Cr): 11.50% – 13.50% (the core element for corrosion resistance, forming a dense chromium oxide passivation film on the surface to resist oxidation and corrosion)
Carbon (C): 0.08% – 0.15% (the lowest carbon content among the Cr13 series, which is key to its high toughness)
Silicon (Si): ≤0.60%
Manganese (Mn): ≤0.80%
Phosphorus (P): ≤0.035% (strictly controlled to avoid material brittleness)
Sulfur (S): ≤0.030% (similarly restricted to ensure toughness)
Iron (Fe): The remaining balance
2. Mechanical Properties
Mechanical properties are significantly influenced by heat treatment. Typical values are as follows:
Property Annealed State Quenched & Tempered State
Tensile strength ≥490 MPa ≥685 MPa
Yield strength ≥245 MPa ≥490 MPa
Elongation (in 50mm) ≥20% ≥18%
Hardness ≤183 HB (Rockwell B ≤88) 21 – 28 HRC (varies with tempering)
3. Physical Properties
Density: Approximately 7.75 g/cm³
Melting point: 1450 – 1510°C (similar to other Cr13 steels)
Thermal conductivity: About 25 W/(m·K) at room temperature
Coefficient of thermal expansion: ~10.0 × 10⁻⁶/°C (within 20 – 100°C)
Magnetic: Yes (due to its martensitic crystal structure)
4. Key Characteristics
Excellent Toughness: Among the Cr13 series (1Cr13, 2Cr13, 3Cr13, 4Cr13), 1Cr13 has the lowest carbon content, resulting in the best toughness and impact resistance. It is less prone to brittle fracture under impact loads.
Moderate Corrosion Resistance: The 11.5% – 13.5% chromium content forms a passivation film, providing resistance to atmospheric corrosion, fresh water, and weak alkaline environments. However, its corrosion resistance is lower than that of austenitic stainless steels (e.g., 304) and is not suitable for strong acids, seawater, or high-chloride environments.
Good Processability:
In the annealed state, it has excellent machinability, making it easy to perform turning, milling, drilling, and other processing operations.
Weldability is better than higher-carbon Cr13 steels, but post-weld heat treatment is still recommended to reduce internal stress and avoid cracking.
Adjustable Performance via Heat Treatment: Quenching and tempering can adjust its strength and hardness. For example, low-temperature tempering (200 – 300°C) increases hardness slightly, while medium-temperature tempering (400 – 600°C) optimizes toughness.
5. Heat Treatment Processes
Annealing: Heat to 800 – 900°C, hold for 2 – 4 hours, then cool slowly with the furnace. This softens the material, eliminates internal stress, and improves machinability.
Quenching: Heat to 1000 – 1050°C (to achieve austenitization), then quench in water or oil. This converts the structure to martensite, increasing strength and hardness.
Tempering: Reheat the quenched steel to 200 – 650°C, hold for a period, then cool. This reduces brittleness and balances mechanical properties (toughness is prioritized in most cases for 1Cr13).
6. Typical Applications
Due to its high toughness and moderate corrosion resistance, 1Cr13 is widely used in:
Mechanical Components: Shafts, gears, bolts, and pump parts that require impact resistance (e.g., water pump shafts in fresh water systems).
Valve Industry: Valve stems, valve discs, and other components in low-pressure, non-corrosive or weakly corrosive pipelines (e.g., freshwater valves).
Medical Devices: Some low-stress surgical instruments (e.g., forceps) that need to withstand repeated sterilization.
Automotive and Aerospace: Parts like hydraulic system components, where toughness and moderate corrosion resistance are required.
Daily Hardware: Faucet cores, door locks, and other parts that need to balance durability and cost.
7. Limitations
Limited Corrosion Resistance: Not suitable for long-term use in strong corrosive environments (e.g., seawater, acid rain, or chemical plants), as it may rust over time.
Lower Hardness: Even after heat treatment, its hardness is lower than that of 2Cr13, 3Cr13, and 4Cr13, so it is not suitable for parts requiring high wear resistance (e.g., cutting tools or high-speed bearings).
In summary, 1Cr13 stainless steel is a martensitic stainless steel focused on toughness. It is an ideal choice for applications that prioritize impact resistance and moderate corrosion resistance, while not demanding extremely high hardness or wear resistance.