C
PM S45VN is a martensitic stainless steel designed to offer
enhanced corrosion and wear resistance over CPM S35VN. Its advanced chemical composition has been meticulously rebalanced to form more chromium carbides, while simultaneously increasing the amount of free chromium in the matrix. By integrating Niobium and Nitrogen in place of some Vanadium and Carbon, this steel achieves an exceptional combination of edge retention, wear resistance, corrosion resistance, and toughness. This makes it the quintessential choice for EDC knife steel.
The
CPM process ensures the production of extremely homogeneous, high-quality steel characterized by superior dimensional stability, grindability, and toughness, far exceeding the qualities of steels produced via conventional melting methods.
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 applications are representative examples. Ensure independent study and evaluation for specific application suitability.
Chemical Composition:
Physical Properties:
Elastic Modulus32 X 106 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)
Although the longitudinal toughness of all grades is approximately 25-28 ft. lbs., the transverse toughness of the CPM grades is significantly higher—four or more times that of 440C and 154CM. This superior transverse toughness indicates that CPM S45VN, CPM S35VN, and CPM S30V are far more resistant to chipping and breaking under side loading conditions, making CPM steels particularly advantageous for larger blades in knifemaking.
Edge Retention(CATRA Testing Relative to 440C)
T
The CATRA (Cutlery & Allied Trades Research Association) test machine executes a precise cutting operation, measuring the number of silica-impregnated cards severed. This test is a benchmark for determining relative wear resistance, which is conveyed in this table, contrasted with a 440C standard. *Estimate derived from 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), maintain for 2 hours, then slow cool at no more than 25°F (15°C) per hour down to 1100°F (595°C). Afterward, furnace cool or allow to cool 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 furnace cool or let cool in still air. For hardened parts: Heat to 25-50°F (15-30°C) below the original tempering temperature, maintain for 2 hours, then furnace cool or let cool in still air.
Straightening:
Optimal when done warm, between 400-800°F (200-425°C).
Hardening Preheat: Heat to 1550-1600°F (845-870°C) and equalize.
Austenitize: Heat to 1900-2000°F (1035-1095°C) and hold at temperature for 15-30 minutes. Quench in air or under positive pressure (minimum 2 bar) to below 125°F (50°C), or perform a salt or interrupted oil quench to approximately 1000°F (540°C), then air cool to below 125°F (50°C).
Temper:
Execute a double temper at 400-750°F (200-400°C). Hold for a minimum of 2 hours each time. (Refer to Table) A freezing treatment may be employed between the first and second tempers to achieve maximum hardenability and must be followed by at least one temper.
NOTE: For optimal stress relieving, temper CPM S45VN at 1000-1025°F (540-550°C). Be aware that tempering within this range may lead to a slight reduction in corrosion resistance.
Size Change:
+0.05 to +0.10% when fully martensitic. The presence of retained austenite can lessen 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 to below 125°F (50°C). Double temper at 600°F (315°C) for a minimum of 2 hours each temper. Cool to hand warm between tempers. A freezing treatment may be incorporated between tempers.
Target hardness: 59-61 HRC.
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