JIS SNCM220 Alloy Steel Bar SNCM220 Round Bars SNCM220 Rods

Product Description

JIS SNCM220 is a premium Nickel-Chromium-Molybdenum (triple-alloy) case-hardening (carburizing) steel grade defined under the Japanese Industrial Standards (JIS G4053).

Supplied as hot-rolled, cold-drawn, or turned round bars and rods, SNCM220 is highly valued in heavy engineering. The combination of nickel, chromium, and molybdenum gives it significantly deeper core hardenability and impact toughness than simpler chromium-manganese steels (like 16MnCr5 or AISI 5115), making it the gold standard for heavy-duty power transmission components.

Technical Specifications & Global Equivalents

SNCM220 is the direct Japanese equivalent to the globally ubiquitous AISI 8620. If you are cross-referencing materials for international manufacturing, use this table:

Chemical Composition (JIS G4053)

The strategic "triple-alloy" blend leverages three elements to optimize performance: Nickel for extreme core toughness and low-temperature impact resistance, Chromium for depth of hardness, and Molybdenum to inhibit grain growth during long carburizing cycles.

• Carbon (C): 0.17% 0.23%

• Nickel (Ni): 0.40% 0.70%

• Chromium (Cr): 0.40% 0.65%

• Molybdenum (Mo): 0.15% 0.25%

• Manganese (Mn): 0.60% 0.90%

• Silicon (Si): 0.15% 0.35%

• Phosphorus (P): max. 0.030%

• Sulfur (S): max. 0.030%

Mechanical Properties & Processing characteristics

• Core Toughness: Unlike simpler alloy steels that can become brittle in heavier section sizes, SNCM220 maintains an exceptionally tough core (tensile strength typically 8501150 MPa after heat treatment) even in ruling sections up to 2.5 inches / 63 mm.

• Case Hardness: After gas carburizing, quenching (typically oil), and low-temperature tempering, the surface achieves a high wear-resistant hardness of 58 to 63 HRC.

• Machinability: Usually supplied in the Annealed condition (max. 217 HBW) or Normalized state. It cuts cleanly with excellent surface finishes, which is crucial for high-speed gear cutting and splining operations.

Typical Engineering Applications

Because SNCM220 round bars absorb high cyclic shocks while resisting aggressive surface wear, they are widely used for:

• Heavy-Duty Drivetrains: Automotive and industrial high-load gears, pinions, splined shafts, bevel gears, and differential spiders.

• Oil & Gas / Mining: High-stress drilling bit shanks, drive collars, and heavy-duty universal joints.

• Fasteners & Friction Parts: Heavy-duty gudgeon pins, piston pins, crankshaft pins, and specialized high-tensile clamping components.