Carpenter 158, C-158 Case Hardening Steel Round Bar, Rods & Bars

Product Description

1. Material Identification and Cross References

• DIN Standard Designation: DIN 1.2735

• DIN Symbol Name: 15NiCr14 / 14NiCr14

• Material Category: Heavy-Duty Nickel-Chromium Case-Hardening Steel

• EN/ISO Standard: EN ISO 4957 / EN 10084

• AFNOR (France): 14NC11 / 15NC11

• AISI/SAE (USA) Equivalent: AISI P6 / Carpenter 158 / UNS T51606

• GOST (Russia): 15Kh2GN2 / 12KhN3A

• BS (UK): 655M13 (EN36B equivalent family)

2. Chemical Composition (Nominal Mass Percent)

• Carbon: 0.12 to 0.17

• Nickel: 3.20 to 3.70

• Chromium: 0.80 to 1.10

• Manganese: 0.40 to 0.70

• Silicon: 0.15 to 0.35

• Phosphorus: Maximum 0.025

• Sulfur: Maximum 0.025

• Iron: Balance

3. Physical Properties

• Density: 7.85 grams per cubic centimeter

• Specific Gravity: 7.85

• Modulus of Elasticity: 210 GPa

• Thermal Conductivity: 34.0 W/m K at room temperature

• Specific Heat Capacity: 460 J/kg K

• Coefficient of Thermal Expansion: 11.5 x 10^-6 per degree Celsius (20 to 100 degrees Celsius)

4. Mechanical Properties

• Annealed Supply Hardness: Maximum 229 HBW (Brinell)

• Core Tensile Strength (Quenched and Tempered): 1000 to 1300 MPa

• Core Yield Strength (0.2% offset): Minimum 780 MPa

• Elongation at Fracture (A5): Minimum 10 percent

• Impact Energy (Charpy-V): Minimum 40 Joules

• Achievable Case Surface Hardness: 58 to 62 HRC (after carburizing, oil quenching, and tempering)

5. Heat Treatment Parameters

• Hot Forming (Forging/Rolling): 850 to 1150 degrees Celsius

• Soft Annealing: 650 to 700 degrees Celsius followed by slow furnace cooling

• Carburizing Temperature: 880 to 930 degrees Celsius

• Core Hardening (First Quench): 850 to 880 degrees Celsius in oil or water

• Case Hardening (Second Quench): 780 to 820 degrees Celsius in oil

• Stress Relieving / Tempering: 150 to 200 degrees Celsius for a minimum of 1 hour per 25 mm section thickness

6. Manufacturing and Supply Specifications

• Available Formats: Hot Rolled Round Bars, Cold Drawn Wire/Rods, Forged Round Blocks, Precision Shafting

• Diameter Range: 10 mm to 600 mm (Standard Stocking: 16 mm to 350 mm)

• Supply Condition: Soft Annealed (+A), Normalized (+N), or Treated for Machinability (+S)

• Surface Finishes: Black As-Rolled/Forged, Peeled/Turned, Centerless Ground, Bright Drawn

• Ultrasonic Testing: SEP 1921 Group 3 Class C/c or E/e compliance available upon request

7. Primary Industrial Applications

• Heavy-duty drive gears, crown wheels, and differential pinions

• Highly stressed shafts, splines, axles, and transmission components

• Plastic injection molds requiring high core strength and polished case finish

• Pneumatic hammer parts, rock drilling tools, and heavy machinery ratchets

• High-tensile structural fasteners, pins, and heavy-duty clamping components