EN19 and EN24 Alloy Steel Induction Hardening Guide
Detailed guide on induction hardening of EN19 and EN24 steels for automotive and heavy equipment manufacturing.
Introduction: Strengthening the Backbone of Industrial Engineering
In the world of automotive and heavy machinery manufacturing, few materials are as reliable as EN19 and EN24 alloy steels. Known for their high tensile strength, wear resistance, and fatigue endurance, these steels are the foundation of components that operate under extreme conditions — from gears and shafts to crankshafts, axles, and spindles.
At Thakur Induction, Ludhiana, we specialize in precision induction hardening of EN19 and EN24 steels, offering manufacturers across Punjab and North India enhanced mechanical performance and durability through advanced heat treatment techniques.
Why EN19 and EN24 Are Ideal for Induction Hardening
Both EN19 and EN24 are nickel-chromium-molybdenum alloy steels, designed for high-stress and heavy-load applications. Their chemical composition allows for deep hardenability and excellent response to induction heat treatment.
| Property | EN19 (AISI 4140) | EN24 (AISI 4340) |
|---|---|---|
| Carbon (%) | 0.35–0.45 | 0.36–0.44 |
| Nickel (%) | — | 1.3–1.7 |
| Chromium (%) | 0.9–1.2 | 0.9–1.2 |
| Molybdenum (%) | 0.2–0.4 | 0.2–0.4 |
EN19 is widely used for medium-load components, while EN24 is preferred for high-load and fatigue-critical parts. Both respond exceptionally well to induction hardening, producing a hard martensitic surface layer with a tough core.
How Induction Hardening Works for EN19 & EN24
At Thakur Induction, we utilize medium-frequency induction systems (10–50 kHz) to ensure precise heating control and uniform case depth.
- Pre-Processing & Cleaning: The component surface is cleaned to remove oil, rust, and contaminants.
- Induction Heating: An induction coil heats the surface layer between 850°C–950°C.
- Quenching: Immediate cooling using polymer or water-based quenching systems transforms the heated layer into martensite.
- Tempering (Optional): Low-temperature tempering (150–200°C) relieves internal stresses.
- Testing & Validation: Hardness testing, case depth measurement, and metallographic inspection ensure consistency.
Every EN steel component undergoes a 100% inspection process before delivery.
Benefits of Induction Hardening for EN19 and EN24 Steels
| Benefit | Impact on Component Performance |
|---|---|
| Increased Surface Hardness (up to 60 HRC) | Enhances wear resistance |
| Tough Core Retained | Prevents breakage under load |
| Precision Control | Uniform case depth (1.5–4 mm) |
| Low Distortion | Suitable for precision-machined parts |
| Faster Processing | Ideal for OEM and batch production |
| Cleaner Operation | No flames or fumes – environment-friendly |
Applications of EN19 and EN24 Induction Hardening
| Industry | Applications |
|---|---|
| Automotive | Drive shafts, gear hubs, transmission pins |
| Agriculture | Tractor spindles, axles, and PTO shafts |
| Heavy Machinery | Rollers, couplings, and pins |
| Forging Units | Tooling dies and mandrels |
Material-Specific Induction Hardening Parameters
| Steel Grade | Hardness (HRC) | Case Depth (mm) | Quenching Medium |
|---|---|---|---|
| EN19 (4140) | 55–58 | 2.0–3.0 | Polymer (10%) |
| EN24 (4340) | 57–60 | 2.5–4.0 | Water or polymer (8%) |
Conclusion: Performance, Precision, and Reliability
EN19 and EN24 steels are ideal for induction hardening due to their high strength and alloy content. Induction heat treatment delivers the best combination of hardness, fatigue resistance, and surface integrity. Thakur Induction, with its advanced systems and skilled team, provides consistent, high-quality results for automotive, heavy machinery, and export-oriented industries.
Looking for EN19 or EN24 Hardening?
Contact Thakur Induction for industrial alloy heat treatment and component hardening job work in Ludhiana and Punjab.