C
PM S45VN is a martensitic stainless steel engineered to deliver
enhanced corrosion and wear resistance compared to CPM S35VN. Its formulation is meticulously balanced to generate more chromium carbides, while simultaneously preserving more free chromium in the matrix. The substitution of Niobium and Nitrogen for portions of the Vanadium and Carbon creates a stellar blend of edge retention, wear resistance, corrosion resistance, and toughness, making it an exceptional choice for EDC knife steel.
The
CPM process results in exceptionally homogeneous, high-quality steel with superior dimensional stability, grindability, and toughness relative to steels produced via traditional 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 typical. Your specific application should be independently studied and evaluated for suitability.
Chemical Composition:
Physical Properties:
Elastic Modulus32 X 10^6 psi
(221 GPa)
Density0.27 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)
While the longitudinal toughness of these grades is approximately 25-28 ft. lbs., the transverse toughness of the CPM grades is four or more times greater than that of 440C and 154CM. The enhanced transverse toughness indicates that CPM S45VN, CPM S35VN, and CPM S30V offer superior resistance to chipping and breaking under side loading conditions. For knifemakers, the higher transverse toughness makes CPM ideal for larger blades.
Edge Retention(CATRA Testing Relative to 440C)
T
The CATRA (Cutlery & Allied Trades Research Association) test machine expertly performs a standardized cutting operation, meticulously measuring the number of silica-impregnated cards that are cut through. This provides a reliable measure of relative wear resistance, which is reported in this table with comparison to a 440C standard. *Estimate based upon extensive market feedback.
Thermal Treatments:
Forging:
2100°F (1150°C). Avoid forging below 1750°F (950°C) for optimal results.
Annealing:
Heat uniformly to 1650°F (900°C), maintain for 2 hours, then cool slowly at a maximum rate of 25°F (15°C) per hour until reaching 1100°F (595°C). Afterward, allow to cool in the furnace or in still air until room temperature is achieved.
Annealed Hardness: Approximately BHN 255
Stress Relieving Annealed Parts:
Heat to 1100-1300°F (595-705°C), hold 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:
Optimal results are achieved when straightening is done warm at 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 using air or positive pressure (minimum 2 bar) to below 125°F (50°C), or use 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 a minimum of 2 hours each time. (See Table) Implementing a freezing treatment between the first and second tempers is beneficial. These treatments ensure maximum hardenability and must always be followed by at least one temper.
NOTE: For the best stress relieving, CPM S45VN can be tempered at 1000-1025°F (540-550°C). However, tempering in this range may slightly decrease corrosion resistance.
Size Change:
Expect a size increase of +0.05 to +0.10% when fully martensitic. Retained austenite presence might reduce net growth. Employ freezing treatments 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 each temper. Ensure to cool to hand warm between tempers. A freezing treatment can be added between tempers for optimal results.
Aim Hardness: Achieve a hardness of 59-61 HRC.
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