CPM S45VN Stainless Steel: The Pinnacle of Martensitic Engineering
CPM S45VN is a state-of-the-art martensitic stainless steel crafted to deliver
exceptional corrosion and wear resistance, surpassing even the renowned CPM S35VN. Its precisely rebalanced chemistry fosters the formation of more chromium carbides while preserving free chromium in the matrix. By integrating Niobium and Nitrogen in place of some Vanadium and Carbon, this steel achieves an outstanding fusion of edge retention, wear resistance, corrosion resistance, and toughness. This makes it the premier choice for EDC knife steel.
The
CPM process ensures the production of extraordinarily homogeneous, high-quality steel, characterized by superior dimensional stability, grindability, and toughness compared to steels produced via conventional melting methods.
Typical Applications:
This high-performance material is perfect for Long-Wearing Specialty Cutlery, Plastic Injection and Extrusion Feed Screws and Dies, Non-Return Valve Components, Pelletizing Equipment, and Wear Components for Food and Chemical Processing. Note: These are just a few typical applications. Always conduct independent studies and evaluations to determine the suitability for your specific applications.
Chemical Composition:
Physical Properties:
Elastic Modulus32 X 10^6 psi
(221 GPa)
Density0.27 lbs./in³
(7.47 g/cm³)
Thermal Conductivity
BTU/hr-ft-°F
W/m-K
cal/cm-s-°C
200°F
93°C
10
17.31
4.13 X 10^-2
Coefficient of Thermal Expansion
°F
°C
in/in/°F
mm/mm/°C
7
0 - 400
(20 - 200)
6.1 X10^-6
(11.0 X10^-6)
70 - 600
(20 - 315)
6.4 X10^-6
(11.5 X10^-6)
Mechanical Properties:
Toughness(Transverse Charpy C-notch Testing)
While all grades exhibit longitudinal toughness of approximately 25-28 ft. lbs., the transverse toughness of CPM grades is significantly higher—four times or more—than that of 440C and 154CM. This elevated transverse toughness means CPM S45VN, CPM S35VN, and CPM S30V are far less prone to chipping and breaking under side loads, making them superior for larger blades in knifemaking.
Edge Retention(CATRA Testing Relative to 440C)
The remarkable edge retention capabilities further set apart CPM S45VN, ensuring long-lasting performance and reliability.
The CATRA (Cutlery & Allied Trades Research Association) test machine executes a standardized cutting operation, gauging the number of silica-impregnated cards sliced. This measure is recognized as an indicator of relative wear resistance, detailed in this table relative to a 440C benchmark. *Estimate based on market feedback.
Thermal Treatments:
Forging:
2100°F (1150°C) - Do not forge below 1750°F (950°C).
Annealing:
Heat to 1650°F (900°C), hold for 2 hours, then slow cool at a rate no faster than 25°F (15°C) per hour to 1100°F (595°C). Afterwards, cool in a furnace or in still air until room temperature is reached.
Annealed Hardness: Approximately BHN 255
Stress Relieving Annealed Parts:
Heat to 1100-1300°F (595-705°C), maintain for 2 hours, then cool in the furnace or in still air. For Hardened Parts: Heat to 25-50°F (15-30°C) below the original tempering temperature, hold for 2 hours, then cool in the furnace or in still air.
Straightening:
Best achieved at a warm temperature of 400-800°F (200-425°C). Hardening Preheat: Heat to 1550-1600°F (845-870°C) until temperature equalizes.
Austenitize:
Heat to 1900-2000°F (1035-1095°C), holding at this temperature for 15-30 minutes. Quench: Use air or positive pressure quenching (minimum 2 bar) to cool below 125°F (50°C), or employ a salt or interrupted oil quench to about 1000°F (540°C), then air cool to below 125°F (50°C).
Temper:
Double temper at 400-750°F (200-400°C), holding for a minimum of 2 hours each time. (Refer to the Table) A freezing treatment may be employed between the first and second tempers. Freezing treatments assist in achieving maximum hardenability and must always be followed by at least one temper.
NOTE: For optimal stress relieving, CPM S45VN may be tempered at 1000-1025°F (540-550°C). Tempering within this range may slightly reduce corrosion resistance.
Size Change:
+0.05 to +0.10% when fully martensitic. The presence of retained austenite can mitigate net growth. When tempering at 400-750°F (200-400°C), freezing treatments might be necessary to minimize retained austenite.
Recommended Heat Treatment:
Austenitize at 1950°F (1065°C). Quench below 125°F (50°C). Double temper at 600°F (315°C) for a minimum of 2 hours each temper. Cool to hand warmth between tempers. A freezing treatment can be included between tempers.
Target Hardness: 59-61 HRC.
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