95Cr18 Stainless Steel Properties

95Cr18 stainless steel is a high-carbon martensitic stainless steel. We often see it specified when customers require high hardness, good wear resistance, and moderate corrosion resistance. It’s a reliable choice for demanding applications.

1. 95Cr18 stainless steel Chemical Composition (GB/T 1220—2007)

The standard chemical composition for 95Cr18 according to GB/T 1220—2007 (mass fraction) is:

• Carbon (C): 0.90% – 1.00%
• Silicon (Si):≤0.80%
• Manganese (Mn):≤0.80%
• Chromium (Cr): 17.00% – 19.00%
• Sulfur (S):≤0.030%
• Phosphorus (P):≤0.040%

Similar grades are found under international standards like JIS (SUS440B, SUS440C) and ASTM (440B, 440C). While the composition ranges might differ slightly, particularly for Carbon and Chromium, they share core characteristics. Aobo Steel understands these variations and can supply material according to specific requirements.

2. 95Cr18 stainless steel Physical Properties

Understanding the physical properties is key to processing 95Cr18 correctly:

Critical Temperatures:Ac1 ≈ 830℃, Ar1 ≈ 810℃

Linear Expansion Coefficient (α):

• 20-100℃: 10.5 × 10⁻⁶℃⁻¹
• 20-200℃: 11.0 × 10⁻⁶℃⁻¹
• 20-300℃: 11.0 × 10⁻⁶℃⁻¹
• 20-400℃: 11.5 × 10⁻⁶℃⁻¹
• 20-500℃: 12.0 × 10⁻⁶℃⁻¹

Properties at 20°C:

• Density: 7.7 g/cm³
• Elastic modulus (E): 203 890 MPa
• Specific heat capacity (cp): 459.8 J/(kg·K)
• Thermal conductivity (λ): 29.3 W/(m·K)
• Electrical resistivity (ρ): 0.60 × 10⁻⁶ Ω·m

These figures influence behavior during forging, heat treatment, and final application.

3. 95Cr18 stainless steel Heat Treatment Guidelines

Correct heat treatment is crucial for achieving the target properties for 95Cr18. Aobo Steel has extensive experience forging and heat treating this grade.

3.1 Forging

• Start Temperature: 1050−1100℃
• Finish Temperature: Above 850℃
• Cooling: Slow furnace cool after forging.
• Note: Avoid excessively fast heating. Maintain a higher final forging temperature and ensure controlled slow cooling post-forging.

3.2 Pre-Heat Treatment (Annealing for Machinability)

• Softening Anneal: Heat to 800−840℃, hold, furnace cool to 500℃, then air cool. Hardness target: ≤255HBW. Microstructure: Pearlite.
• Full Anneal: Heat to 840−860℃, then furnace cool. Hardness target: ≤255HBW.
• Note: Cooling rate during annealing impacts final hardness. Slower cooling generally results in lower hardness within the target range.

3.3 Hardening (Quenching)

• Temperature: 1030−1070℃
• Medium: Oil quench.
• Resulting Hardness: ≥55HRC.
• Note: Quenching temperature directly affects hardness. Higher temperatures generally yield higher hardness (e.g., 1050℃ quench can achieve 60HRC), but also influence retained austenite levels.

3.4 Tempering

Tempering adjusts hardness and toughness after quenching.

• Low Temper (High Hardness):200−300℃. Hardness: 56- 60HRC. This range typically offers better corrosion resistance. Tempering between 160−200℃ is often recommended.
• High Temperature (Improved Toughness):500−600℃. Hardness: 40- 53HRC.
• Stress Relief: After grinding, a final tempering at 130−140℃ can relieve residual stresses.

3.5 Cold Treatment (Optional)

• Process: Cool to −75 to −80℃ for 1 hour after quenching.
• Purpose: Reduces retained austenite, potentially increasing hardness by 1-2 HRC and improving dimensional stability.
• Consideration: Can reduce impact toughness; evaluate based on application needs.

4. 95Cr18 stainless steel Mechanical Properties

The final mechanical properties depend directly on the chosen heat treatment cycle.

• Hardness: Typically >55HRC after quenching (1000−1050℃) and low tempering (200−300℃).
• Toughness & Corrosion Resistance: These properties are balanced by carefully selecting quenching and tempering temperatures. Higher tempering temperatures generally reduce hardness but can improve toughness. Lower tempering temperatures often favor corrosion resistance.

5. Applications for 95Cr18

Thanks to its high hardness, wear resistance, and acceptable corrosion resistance, 95Cr18 is used in:

• Cutting Tools: High-quality knives, cutlery, scissors, surgical blades, and slicing machine blades requiring sharp edges and resistance to mild corrosives.
• Molds: Plastic injection molds, especially those requiring high wear resistance and operating under load or in mildly corrosive environments.
• Wear-Resistant Components: Shafts, pump parts, valve components, fasteners, springs, and measuring tools (gauges) where durability and resistance to wear and corrosion are necessary.
• Cold Work Dies (Specific Cases): While grades like Cr12MoV are common, 95Cr18 can be an option where additional corrosion resistance is beneficial alongside wear resistance.

At Aobo Steel, we supply 95Cr18 for many of these demanding applications. With over 20 years of forging experience and strong supplier relationships, we can provide high-quality 95Cr18 tailored to your processing and performance needs. Contact us to discuss your requirements.

6. 95Cr18 equivalent grades

• AISI (USA): 440C
• JIS (Japan): SUS440C
• EN/DIN (Europe): X105CrMo17 (1.4125)