A real, organized buyer base
Pakistan's auto parts forging trade isn't informal either. PAAPAM, the Pakistan Association of Automotive Parts & Accessories Manufacturers, has member companies doing closed-die forging, CNC gear hobbing, and in-house heat treatment, carburizing and nitriding included, concentrated along Lahore's GT Road and Shalimar Town area and in Karachi's SITE and Bin Qasim industrial zones. These are established, often decades-old businesses: Precision Forging in Lahore specializes in closed-die forging for crankshafts, engine parts, and axle components across automotive, aerospace, agriculture, and construction customers, while Shaheen Engineering, also on GT Road, has been producing shaft rear axles, wheel axles, crown wheels and pinions, and hydraulic lift arms since 1974. Several PAAPAM members list gear manufacturing, CNC gear shaping, and coordinate measuring machine inspection as standard capabilities, this is a technically capable trade, not a low-precision commodity market.
| Property | 4140 Alloy Steel | 8620 Alloy Steel | 5140 Alloy Steel |
|---|---|---|---|
| Category | Alloy Steel | Alloy Steel | Alloy Steel |
| Carbon (C) | 0.38 to 0.43% | 0.18 to 0.23% | 0.38 to 0.43% |
| Chromium (Cr) | 0.8 to 1.1% | 0.4 to 0.6% | 0.7 to 0.9% |
| Nickel (Ni) | Not published | 0.4 to 0.7% | Not published |
| Molybdenum (Mo) | 0.15 to 0.25% | 0.15 to 0.25% | Not published |
| Hardness | Not published | 149 HB | 167 HB |
| Density | 7.85 g/cm³ | 7.85 g/cm³ | Not published |
| Group | Chromium-molybdenum low alloy steel | Nickel-chromium-molybdenum case-hardening steel | Chromium alloy steel |
Confirm against the mill test certificate before specifying. Chat with us if you need help matching a grade to a job.
The checklist
Does the part need a hard wear surface over a tough core? If yes and the shop has carburizing capability, quote 8620. It's the standard case-hardening grade for gears and transmission parts across the PAAPAM member base, and several shops already carburize in-house, so this pairs naturally with existing local capability rather than requiring the customer to source outside heat treatment.
Does the part need to be strong and hard through the entire section, no case required? Quote 4140 for general shafts and gears, or a plain carbon grade like 1045 if the application doesn't need alloy steel's extra hardenability at all, a meaningful cost difference worth raising with a price-sensitive customer.
Is this a genuinely high-stress application, landing gear, heavy crankshafts, aircraft-grade components? 4340 is the step up from 4140 when core toughness under extreme load is the deciding factor, though most Pakistani demand stays in general automotive and machinery territory rather than aerospace, so it's worth confirming the actual load case before quoting the more expensive grade.
Does the part need moderate strength without alloy steel's full cost? 5140 sits between plain carbon steel and the nickel-chromium-molybdenum grades, a reasonable middle option for shafts and fasteners that don't need 4140's full alloying, worth keeping in stock specifically for customers who'd otherwise overpay for 4140 on a job that doesn't need it.
Why this matters for a supplier, not just a buyer
A forging shop that gets the wrong grade doesn't find out until the part fails in service, sometimes not until it's already installed in a customer's vehicle or machinery, at which point the cost of the mistake is far higher than the price difference between grades would have been. Asking the right qualifying questions upfront, is this case-hardened or through-hardened, what's the actual load case, protects both the supplier's reputation and the forging shop's relationship with their own customer, and it's the kind of technical conversation that turns a one-time order into a repeat account.
Sourcing reality
All four grades are import-only, sourced from international specialty mills rather than rolled domestically, which makes consistent supply and accurate mill certification as important as price when competing for PAAPAM member business, particularly for shops supplying original equipment manufacturers who require traceable material certificates for every batch.
Supplying a forging shop and need help specifying a grade? Reach out with the part's application and load requirements.