AISI SAE 5115 Alloy Steel Bar 5115 Round Bars 5115 Rods

Product Description

AISI/SAE 5115 is a low-carbon, chromium-alloyed case-hardening (carburizing) steel standard defined by the American Iron and Steel Institute and the Society of Automotive Engineers.

Supplied primarily as cold-finished or hot-rolled round bars and rods, this grade is engineered for high-precision components that demand an extremely hard, wear-resistant outer surface (case) alongside a structural, impact-resistant core.

Technical Specifications & Cross-References

AISI 5115 sits perfectly within the global family of manganese-chromium and chromium-only carburizing steels. When sourcing equivalents for international projects, look for:

Chemical Composition (ASTM A29 / SAE J404)

The addition of chromium provides AISI 5115 with superior response to case hardening and deeper hardenability compared to standard plain carbon steels (like 1018).

• Carbon (C): 0.13% 0.18% (keeps the inner core ductile and tough after quenching)

• Chromium (Cr): 0.70% 0.90% (promotes chromium-carbide formation for high surface hardness)

• Manganese (Mn): 0.70% 0.90%

• Silicon (Si): 0.15% 0.35%

• Phosphorus (P): max. 0.035%

• Sulfur (S): max. 0.040%

Mechanical Profiles & Heat Treatment Behavior

• Machinability: In its annealed or cold-drawn supply state, AISI 5115 exhibits excellent machinability (roughly 70-75% of AISI 1212 free-machining steel), reducing tool wear during complex turning, boring, and gear cutting.

• Surface Hardness: Following carburizing, oil quenching, and low-temperature tempering, the outer layer easily reaches a hardness of 58 to 62 HRC, making it exceptionally resistant to abrasive wear and adhesive scuffing.

• Core Limitations: Because it is a lean alloy, its core hardenability is localized. It yields maximum core toughness in small-to-medium cross-sections (typically under 2 inches / 50 mm in diameter).

Typical Engineering Applications

Because AISI 5115 round bars can handle localized sliding friction and cyclic shock loading simultaneously, they are common choices for:

• Automotive & Drivetrain: Light-duty gears, pinions, splined shafts, worm gears, and clutch components.

• Industrial Fasteners: Specialized pins, heavy-duty socket bolts, dowels, and gudgeon pins.

• Machinery Components: Bushings, cams, pistons, and universal joint linkages.