High-Tensile, Through-Hardening Steel — Is EN19 the Engine of Your Project? 

A premium low-alloy steel round bar, EN19 Round Bars (also called 709M40 or 4140) is renowned for its outstanding toughness, through-hardening qualities, and high tensile strength. For high-stress components where performance and dependability are essential, it is the preferred material. 

EN19 Round Bars — Key Specifications 

Bright Drawn vs. Black EN19 Round Bars — Choosing Your Base Material 

Bright Drawn EN19 Round Bar A cold-finished bar with exact dimensional precision and a superb surface polish. This state is perfect for uses where the bar is utilized in a visible end component or requires little machining. 

• Best for: Precision shafts, rollers, and high-quality machined parts. 

Black EN19 Round Bar A distinctive black mill scale on a hot-rolled bar. This is the most cost-effective choice, intended for applications where the bar will be completely forged, machined, or heat-treated, negating the need for a surface finish. 

• Best for: Heavy-duty applications, general high-strength fabrication, and parts for additional processing. 

The Power of Heat Treatment: Unleashing EN19's Potential 

The main benefit of EN19 Round Bars is its exceptional heat treatment response, which enables customization for certain demanding applications. 

• Through-Hardening EN19: The round bar is ideal for items that require constant strength throughout, such as gears and axles, because its entire cross-section may be hardened to a high degree of homogeneity. 

• Tensile Strength: Milder steels like EN8 or EN9 are greatly outperformed by EN19, which may reach tensile strengths of over 1000 MPa after heat treatment. 

• Tempering: Engineers can precisely adjust the ideal ratio of ultimate hardness to toughness for their application using the tempering process. 

4140 Alloy Steel vs. EN19 Round Bars — Decoding the Standards 

The usual AISI/SAE grade is 4140, while the British standard (BS 970) code is EN19. They are quite similar chemically and functionally. Regardless of the standard listed on your technical drawing, EN19/4140 round bar is now a standard combination search term that guarantees you will find the correct material. 

Top Applications for EN19 Round Bars 

• Automotive & Aerospace: Essential for gears, landing gear parts, crankshafts, high-tensile shafts, and other high-stress components. 

• Oil & Gas Industry: Utilized in drilling equipment, mandrels, downhole tools, and valve parts where durability and dependability are crucial. 

• Power Transmission & Heavy Machinery: The best option for heavy-duty pins, axles, spindles, eccentric shafts, and hydraulic piston rods. 

• Tooling & Manufacturing: Used for mold bases, dies, jigs, and fittings that need to be very stable and resistant to wear. 

Understanding Cost & Getting a Quote 

Diameter, length, condition (bright drawn vs. black), and—most importantly—any further heat treatment (hardened and tempered) all affect the cost of EN19 Round Bars round bar. Please contact us with the details of your project so that we can provide you with an accurate quote. 

➤ Get a Competitive Quote for EN19/4140 Round Bar 

Frequently Asked Questions (FAQ) 

What is the typical hardness of heat-treated EN19? 

Oil quenching allows EN19 Round Bars to be hardened to a range of 55-60 HRC (Rockwell C), after which it can be tempered to attain the ideal hardness and toughness ratio for the application (e.g., 35-40 HRC for many shafts). 

Can you supply EN19 round bar cut to size and machined?  

Indeed. To produce completed diameters and tolerances that are prepared for installation, we provide centerless grinding and turning services in addition to precise saw cutting to length. 

Should I choose EN19 Round Bars or EN8 for my shaft?  

For general-purpose, low-to-medium stress applications, go for EN8. When you need a component with much higher tensile strength, resistance to wear, and the capacity to through-harden it for optimal performance, go with EN19. 

Is EN19 Round Bars suitable for welding?  

Although it can be carefully welded, pre-heating and post-weld heat treatment (PWHT) are necessary to prevent cracking and restore mechanical qualities. Usually, it is not categorized as a "readily weldable" steel. 

Do you supply normalized or pre-hardened EN19?  

Indeed, in order to cut down on downstream processing time, we can provide EN19 Round Bars in a variety of states, such as normalized or pre-hardened to a particular hardness (for example, 30 HRC). 

Dimensions:

OD 3mm - 460mm

30mm to 450mm x 6000mm

Finish:

Hot Rolled + Black Surface + UT C/c

Forged + Bright Surface + UT D/d

Disclaimer
The information and data presented herein are typical or average values and are not a guarantee of maximum or minimum values. Applications specifically suggested for material described herein are made solely for the purpose of illustration to enable the reader to make his own evaluation and are not intended as warranties, either express or implied, of fitness for these or other purposes. There is no representation that the recipient of this literature will receive updated editions as they become available.