4140 Alloy Steel

Chemical Composition

Physical Properties

Density (kg/m³)

7850

Melting point (°C)

1416

Also known as

Typical Applications

• Shafts
• Gears
• Fasteners
• Automotive and machinery components

Buying This Grade in Pakistan

A workhorse for Pakistan's auto parts forging sector, PAAPAM-member shops along Lahore's GT Road and in Karachi's SITE and Bin Qasim industrial areas forge and CNC-machine shafts, gears, and axle components from grades in this family, often with in-house carburizing or nitriding.

Related reading

• Sourcing steel for auto parts forging: a PAAPAM supplier's grade checklist

  A practical grade-selection checklist for Pakistani auto parts forging shops, built around what PAAPAM-member companies actually forge and heat treat.

• Gear and shaft steel for Pakistan's forging sector: 4140, 8620, and 5140 side by side

  Three alloy steel grades cover most of the gear and shaft work in Pakistan's forging sector. Here's how to tell which one a given part actually needs.

• 8620 vs 8640: case-hardening vs through-hardening, which one and why

  The difference between 8620 and 8640 alloy steel comes down to one question: does the part need a hard case over a tough core, or uniform hardness throughout?

• 4140 alloy steel: the forging industry's workhorse, explained

  Why 4140 shows up in nearly every Pakistani auto parts forging shop, and what its composition actually gives you.

• 1045 carbon steel: the most ordered grade you've never thought about

  1045 doesn't get the attention alloy or tool steels do, but it's likely the highest-turnover grade in a Pakistani steel supplier's catalog. Here's why.