High Tensile EN Steel Series CNC Machining
The EN Series (British Standard BS 970) represents a family of engineering steels ranging from medium-carbon grades to high-alloy nickel-chrom-moly steels. Unlike basic mild steel, these grades are engineered for performance. At JUCHENG, we have deep expertise in machining these specific European grades. From the versatile EN8 used for general axles to the ultra-high-strength EN24T and EN39 used in heavy-duty gearboxes, we provide precision turning and milling services. We understand the specific heat-treatment conditions (like the "T" condition) required to extract maximum durability from these alloys.
EN Steel Series
JUCHENG's EN Steel Machining Capabilities
Processing high-tensile steels requires rigid equipment and metallurgical knowledge:
- Hard Turning: Grades like EN24T are often supplied in the hardened and tempered condition (approx. 248-302 HB). We use robust CNC lathes to machine these pre-hardened steels to precise tolerances without further heat treatment.
- Gear Cutting: We specialize in hobbing and shaping gears from EN39 and EN24T, creating components that can withstand massive torque loads.
- Heat Treatment: For EN8 and EN16, we offer induction hardening or through-hardening services to improve surface wear resistance.
- Large Shaft Processing: Our facility can handle long, heavy drive shafts typical of EN steel applications, ensuring concentricity and straightness.
Advantages of CNC Machining EN Steels
| Advantage | Detailed Description | Key Benefit |
| Range of Strength | Offers a stepped range from moderate (EN8) to extreme strength (EN24T). | Allows engineers to select the exact cost-to-performance ratio needed. |
| Pre-Hardened Availability | EN24T comes hardened/tempered. | Eliminates post-machining heat treat risks (distortion/cracking). |
| Impact Resistance | Nickel-bearing grades (EN24/39) have superior toughness. | Critical for parts subject to sudden shock loads or vibration. |
| Wear Resistance | Responsive to surface hardening. | Extends the life of moving parts like crankpins and gears. |
Detailed Material Profiles (EN Family)
We stock and process the complete range of BS 970 engineering steels:
| Grade Category | BS 970 No. | Characteristics & Ideal Uses |
| EN8 (080M40) | Medium Carbon | Characteristics: Unalloyed medium carbon steel (similar to 1045). Good tensile strength. Can be flame or induction hardened. Uses: General purpose axles, shafts, studs, keys, automotive connecting rods. |
| EN16 (605M36) | Mn-Mo Steel | Characteristics: Manganese-Molybdenum steel. Good ductility and shock resistance. A cost-effective alternative to higher alloy steels for medium-stress parts. Uses: High-tensile bolts, lifting gear pins, connector rods. |
| EN24T (817M40T) | Ni-Cr-Mo Steel | Characteristics: High tensile alloy steel supplied in "T" condition (850-1000 MPa). Excellent wear and shock resistance. Deep hardenability. Uses: Heavy-duty gears, power transmission shafts, crane axles, high-strength studs. |
| EN29 / EN39 | Case Hardening | Characteristics: High Nickel-Chrome alloys designed for case hardening. EN39 (4.5% Ni) offers massive core strength and a hard surface. Uses: Heavy-duty gears for trucks/trains, rollers, cams requiring extreme wear resistance. |
CNC Machining Guidelines
- Tooling for "T" Condition: Machining EN24T requires coated carbide tools and lower cutting speeds than mild steel due to its hardness and toughness.
- Coolant: High lubricity coolant is recommended to improve surface finish, especially on the "gummier" EN16 grades.
- Welding: Caution. High alloy grades like EN24T are difficult to weld and require specific pre/post-heat procedures. EN8 is weldable but requires care.
- Finishing: These steels can be ground to very fine finishes (Ra 0.4) for bearing journals.
Application Scenarios
- Automotive & Racing: Crankshafts, axles, steering knuckles, high-tensile fasteners.
- Heavy Industry: Crane pulleys, hydraulic rams, rock crusher shafts.
- Power Transmission: Gearbox gears (spur/helical), output shafts, couplings.
- Tooling: Press tools, die holders, high-strength jigs.
Physical Properties Table
Comparison: EN8 (General) vs EN24T (High Performance):
| Property | EN8 (Normalized) | EN24T (Hardened/Tempered) | Unit |
| Tensile Strength | 550 - 700 | 850 - 1000 | MPa |
| Yield Strength | 280 | 680 - 850 | MPa |
| Hardness | 152 - 207 HB | 248 - 302 HB | Brinell |
| Elongation | 16 | 13 | % |
| Shock Resistance | Good | Excellent | - |
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