Composition
CPM S45VN is a high-performance martensitic stainless steel meticulously engineered to provide
exceptional corrosion and wear resistance, surpassing even the impressive CPM S35VN. Its rebalanced chemistry enables the formation of additional chromium carbides while retaining more free chromium in the matrix. Utilizing Niobium and Nitrogen, this steel substitutes part of its Vanadium and Carbon content, resulting in an outstanding blend of edge retention, wear resistance, corrosion resistance, and toughness. This makes CPM S45VN the ultimate choice for an everyday carry (EDC) knife steel.
The
CPM process creates exceptionally homogeneous, high-quality steel that boasts superior dimensional stability, grindability, and toughness, compared to steels made through conventional melting techniques.
Typical Applications:
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 typical applications. Conduct an independent study to evaluate the material's suitability for your specific application.
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 the longitudinal toughness of these steel grades remains around 25-28 ft. lbs., the transverse toughness of CPM grades is significantly superior, being four or more times greater than that of 440C and 154CM. This enhancement ensures that CPM S45VN, CPM S35VN, and CPM S30V are much more resistant to chipping and breakage in scenarios involving side loading. For knife making, this increased transverse toughness is particularly beneficial for larger blades.
Edge Retention(CATRA Testing Relative to 440C)
Performance
The CATRA (Cutlery & Allied Trades Research Association) test machine executes a standard cutting operation to measure the number of silica-impregnated cards that are severed. This serves as a benchmark for relative wear resistance, evident in this table when compared to a 440C standard. *Estimate based on market feedback.
Thermal Treatments:
Forging:
Heat to 2100°F (1150°C). Do not forge below 1750°F (950°C).
Annealing:
Heat to 1650°F (900°C) and hold for 2 hours. Cool slowly, not exceeding 25°F (15°C) per hour, until reaching 1100°F (595°C). Then, furnace cool or let cool in still air to room temperature.
Annealed Hardness: Approximately BHN 255.
Stress Relieving Annealed Parts:
Heat to 1100-1300°F (595-705°C) and hold for 2 hours. Then, furnace cool or let cool in still air. For hardened parts: Heat to 25-50°F (15-30°C) below the original tempering temperature, hold for 2 hours, then furnace cool or let cool in still air.
Straightening:
Best performed warm at 400-800°F (200-425°C). Preheat for Hardening: Heat to 1550-1600°F (845-870°C) and equalize.
Austenitize:
Heat to 1900-2000°F (1035-1095°C) and hold for 15-30 minutes. Quench: Use air or positive pressure quench (minimum 2 bar) to below 125°F (50°C), or employ salt or interrupted oil quench to approximately 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 at least 2 hours each time. A freezing treatment may be used between the first and second temper to achieve maximum hardenability, but it must always be followed by at least one temper.
NOTE: For optimal stress relieving, CPM S45VN can be tempered at 1000-1025°F (540-550°C). Be aware that tempering in this range may slightly decrease corrosion resistance.
Size Change:
+0.05% to +0.10% when fully martensitic. The presence of retained austenite may reduce net growth. Freezing treatments may be required to minimize retained austenite when tempering at 400-750°F (200-400°C).
Recommended Heat Treatment:
Austenitize at 1950°F (1065°C). Quench to below 125°F (50°C). Double temper at 600°F (315°C) for a minimum of 2 hours each. Cool to hand warm between tempers. A freezing treatment can be included between tempers.
Target hardness: 59-61 HRC.
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