SAE 1140 carbon steel

Introduction

We manufacture forging ingots, billets, and blooms in carbon steel specifically for SAE 1140, designed for medium to high strength engineering applications.

SAE 1140 is a medium carbon, high manganese steel that offers good strength, improved hardenability, and excellent machinability compared to standard plain carbon steels. The elevated manganese content helps achieve better response to heat treatment and more uniform mechanical properties.

This grade is widely used in automotive, general engineering, and machined components where a balance of strength, toughness, and cost-effectiveness is required.

Chemical composition

Element Content (%) Function / effect
Carbon (c) 0.37 – 0.44 Provides strength, hardness, and wear resistance
Manganese (mn) 1.35 – 1.65 Improves hardenability and toughness
Silicon (si) 0.15 – 0.35 Enhances strength and elasticity
Phosphorus (p) Max 0.040 Controlled to maintain toughness
Sulphur (s) 0.040 – 0.060 Improves machinability

Mechanical properties

  • Tensile strength: 650 – 800 MPa
  • Yield strength: 420 – 520 MPa
  • Elongation: 10 – 16 %
  • Hardness: 200 – 255 HB

(properties may vary with section size and heat treatment)

Heat treatment

  • Normalizing – refines grain structure and improves uniformity
  • Quenching and tempering – increases strength and toughness
  • Stress relieving – reduces residual stresses after machining

Key features and benefits

  • Higher manganese for better hardenability
  • Good machinability and consistent performance
  • Suitable for heat-treated components
  • Cost-effective alternative to low alloy steels
  • Reliable for medium to high load applications

Typical applications

  • Automotive shafts and axles
  • Gears and pinions
  • Studs, bolts, and fasteners
  • Machined and forged components
  • General engineering parts

Equivalent steel grades

  • En 1.1165 (c40e) – approximate
  • Din c40
  • Is 40mn (comparable properties)

Why Choose SAE 1140 For Your Application?

SAE 1140 Is Ideal For Applications Requiring High Machining Efficiency Along With Moderate Strength. Its Resulphurized Composition Allows Faster Machining Speeds, Improved Surface Finish, And Reduced Production Costs. It Is Especially Suitable For Large-Scale Manufacturing Of Precision Components.

Comparison table for similar grades

Grade Carbon (%) Manganese (%) Key difference
SAE 1040 0.37 – 0.44 0.60 – 0.90 Lower mn, lower hardenability
SAE 1140 0.37 – 0.44 1.35 – 1.65 Higher mn, better strength
SAE 1144 ~0.44 ~1.50 Resulfurized, higher machinability
En 1.1165 (c40e) ~0.40 ~0.70 Lower mn european grade

Summary

SAE 1140 is a robust medium carbon, high manganese steel offering good strength, improved hardenability, and excellent machinability. It is an ideal choice for automotive and general engineering applications where consistent performance and cost-effective heat treatment response are essential.