Overview
CPM S45VN is a state-of-the-art martensitic stainless steel engineered to provide
superior corrosion and wear resistance compared to CPM S35VN. By rebalancing the chemistry, more chromium carbides are formed, while more free chromium remains in the matrix. Utilizing niobium and nitrogen instead of some vanadium and carbon, this steel exhibits an exceptional blend of edge retention, wear resistance, corrosion resistance, and toughness. These characteristics make it the perfect choice for everyday carry (EDC) knife steel.
The
CPM process yields extraordinarily uniform, high-quality steel, distinguished by outstanding dimensional stability, grindability, and toughness, surpassing those produced by conventional melting techniques.
Typical Applications:
Long-Wearing Specialty Cutlery, Plastic Injection and Extrusion Feed Screws and Dies, Non-Return Valve Components, Pelletizing Equipment, Wear Components for Food and Chemical Processing. Note: These are some typical applications. Your specific application should be independently evaluated for suitability.
Chemical Composition:
Physical Properties:
Elastic Modulus32 x 10 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 10²
Coefficient of Thermal Expansion
°F
°C
in/in/°F
mm/mm/°C
7
0 - 400
(20 - 200)
6.1 x 10
(11.0 x 10)
70 - 600
(20 - 315)
6.4 x 10
(11.5 x 10)
Mechanical Properties:
Toughness(Transverse Charpy C-notch Testing)
While the longitudinal toughness of these grades is about 25-28 ft. lbs., the transverse toughness of CPM grades is four or more times better than that of 440C and 154CM. This higher transverse toughness indicates CPM S45VN, CPM S35VN, and CPM S30V are significantly more resistant to chipping and breakage under side loading conditions. For knifemaking, this translates to enhanced performance for larger blades.
Edge Retention(CATRA Testing Relative to 440C)
Conclusion
The CATRA (Cutlery & Allied Trades Research Association) test machine executes a standardized cutting procedure, quantifying the number of silica-impregnated cards it slices through. This assessment is recognized as a benchmark for relative wear resistance, with results displayed in comparison to a 440C standard. *Estimate based upon market feedback.
Thermal Treatments:
Forging:
Heat to 2100°F (1150°C), ensuring not to forge below 1750°F (950°C).
Annealing:
Elevate temperature to 1650°F (900°C), maintain for 2 hours, then gradually lower by no more than 25°F (15°C) per hour until reaching 1100°F (595°C). Post this, either furnace cool or allow cooling in still air to ambient room temperature.
Annealed Hardness: Approximately BHN 255
Stress Relieving Annealed Parts:
Heat parts to 1100-1300°F (595-705°C), sustain for 2 hours, then either furnace cool or let them cool in still air. For hardened parts, heat to 25-50°F (15-30°C) below the original tempering temperature, sustain for 2 hours, then furnace cool or air cool.
Straightening:
Optimal results achieved when warming between 400-800°F (200-425°C). For hardening, preheat by raising the temperature to 1550-1600°F (845-870°C) and equalize.
Austenitize:
Raise to 1900-2000°F (1035-1095°C), maintaining the temperature for 15-30 minutes. Quench using air or positive pressure (minimum 2 bar) down to below 125°F (50°C), or use a salt or interrupted oil quench to around 1000°F (540°C) and then air cool below 125°F (50°C).
Temper:
Double temper between 400-750°F (200-400°C), each session lasting a minimum of 2 hours. (Refer to Table) A freezing treatment can be applied between the first and second temper to achieve maximum hardenability, ensuring it is followed by at least one temper.
NOTE: For optimal stress relief, CPM S45VN may be tempered between 1000-1025°F (540-550°C). Be aware that tempering within this range might slightly reduce corrosion resistance.
Size Change:
Expect an increase of +0.05 to +0.10% when fully martensitic. The presence of retained austenite could lessen the overall growth. Freezing treatments might be necessary when tempering at 400-750°F (200-400°C) to minimize retained austenite.
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 per temper. Cool to hand warm between tempers. Optionally, a freezing treatment can be included between tempers.
Target hardness: Achieve 59-61 HRC.
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