C
PM S45VN is a martensitic stainless steel designed to offer
improved corrosion and wear resistance over CPM S35VN. Its chemistry has been meticulously rebalanced to form more chromium carbides, while simultaneously leaving an abundance of free chromium in the matrix. The incorporation of Niobium and Nitrogen, replacing some Vanadium and Carbon, results in an outstanding blend of edge retention, wear resistance, corrosion resistance, and toughness properties, making this the quintessential choice for an EDC knife steel.
The
CPM process yields exceptionally homogeneous, high-quality steel known for superior dimensional stability, grindability, and toughness compared to steels produced by conventional melting practices.
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 studied and evaluated for suitability.
Chemical Composition:
Physical Properties:
Elastic Modulus32 X 10^6 psi
(221 GPa)
Density 0.27 lbs./in^3
(7.47 g/cm^3)
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 four of these grades is about 25-28 ft. lbs., the transverse toughness of the CPM grades is four or more times that of 440C and 154CM. The higher transverse toughness results indicate that CPM S45VN, CPM S35VN and CPM S30V are significantly more resistant to chipping and breaking in applications that may encounter side loading. In knifemaking, the higher transverse toughness makes CPM especially suitable for larger blades.
Edge Retention (CATRA Testing Relative to 440C)
T
The CATRA (Cutlery & Allied Trades Research Association) test machine executes a precise cutting operation, meticulously measuring the number of silica-impregnated cards that are sliced. This process is esteemed as an assessment of relative wear resistance, benchmarked against a 440C standard. *Estimate based upon market feedback.
Thermal Treatments:
Forging:
Forge at a temperature of 2100°F (1150°C) and ensure not to forge below 1750°F (950°C).
Annealing:
Commence heating to 1650°F (900°C) and maintain for 2 hours. Follow by a slow cooling process, not exceeding 25°F (15°C) per hour until reaching 1100°F (595°C). Finally, cool in a furnace or still air until room temperature is achieved.
Annealed Hardness: Achieves approximately BHN 255.
Stress Relieving Annealed Parts:
Heat to a range of 1100-1300°F (595-705°C), maintaining for 2 hours, then proceed with furnace cooling or still air cooling. For hardened parts, heat to 25-50°F (15-30°C) below the original tempering temperature, hold for 2 hours, and then cool in the same manner.
Straightening:
Optimal when performed warm at 400-800°F (200-425°C). Hardening Preheat involves heating to 1550-1600°F (845-870°C) with equalizing.
Austenitize:
Heat to a range of 1900-2000°F (1035-1095°C), holding at temperature for 15-30 minutes. Quenching can be executed through air or positive pressure (minimum 2 bar) to below 125°F (50°C), or via salt or interrupted oil quenching to approximately 1000°F (540°C), then air cooling to below 125°F (50°C).
Temper:
Double tempering is recommended at 400-750°F (200-400°C), with each cycle lasting a minimum of 2 hours. Optionally, a freezing treatment can be applied between the first and second temper to enhance hardenability, followed by an additional temper.
NOTE: For premium stress relieving, CPM S45VN can be tempered at 1000-1025°F (540-550°C). However, this may slightly reduce corrosion resistance.
Size Change:
Changes of +0.05 to +0.10% when fully martensitic can be expected. The presence of retained austenite might reduce net growth. Freezing treatments may be necessary when tempering at 400-750°F (200-400°C) to minimize retained austenite.
Recommended Heat Treatment:
Austenitize at 1950°F (1065°C), followed by quenching to below 125°F (50°C). Double temper at 600°F (315°C) for a minimum of 2 hours per cycle, cooling to hand warm between cycles. Optionally, include a freezing treatment between tempers.
Target Hardness: Aim for a hardness of 59-61 HRC.
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