EN19 is a medium-carbon steel with 0.9–1.2% chromium and molybdenum added. The alloying lets it harden right through the section, so a quenched and tempered bar delivers 900–1,300 MPa tensile strength depending on diameter, with good toughness. Engineers choose it for shafts, gears, crankshafts, connecting rods and high-strength bolts, where plain carbon steel runs out of strength at larger diameters.
OneKaizen sources EN19 from India's leading mills and international partner mills and supplies it as rolled round bars in Ø 16–500 mm, bright bars in Ø 8–160 mm, forged bars in Ø 250–1,030 mm and shafts in Ø 25–500 mm. Delivery condition is your choice: hot rolled, annealed, quenched and tempered, cold drawn, peeled, or pre-hardened to 28–34 HRC. Every consignment ships with a mill test certificate.
EQUIVALENT GRADES
EN19 Equivalents
Direct means the same grade under another name. Close means the same alloy concept with slightly different limits, commonly substituted. Approximate means similar use with real differences: check with us before substituting.
| Standard | Designation | Match |
|---|---|---|
| Old BS EN | EN19 | Direct |
| Old BS EN | EN19A | Close |
| BS 970 | 709M40 | Direct |
| BS 970 | 708M40 | Close |
| IS | 40Cr1Mo28 | Close |
| EN | 42CrMo4 (1.7225) | Close |
| DIN W.Nr. | 1.7225 | Close |
| AISI/SAE | 4140 | Close |
| UNS | G41400 | Close |
| JIS | SCM440 | Close |
| KS | SCM440 | Close |
| GB | 42CrMo | Close |
| UNI | 42CrMo4 | Direct |
| UNE | 42CrMo4 | Direct |
| TS | 42CrMo4 | Direct |
EN19 Chemical Composition
Per EN 10083-3 (42CrMo4). BS 970 709M40 (EN19) is C .36-.44, Mn .70-1.00, Cr .90-1.20, Mo .25-.35; SAE 4140 is C .38-.43, Mn .75-1.00, Cr .80-1.10, Mo .15-.25
| Element | Range, wt % | Range chart |
|---|---|---|
| C | 0.38 – 0.45 | |
| Si | ≤ 0.4 | |
| Mn | 0.6 – 0.9 | |
| P | ≤ 0.025 | |
| S | ≤ 0.035 | |
| Cr | 0.9 – 1.2 | |
| Mo | 0.15 – 0.3 |
EN19 and Its Equivalents: Chemical Composition
Equivalent grades are written to different standards, so their limits differ slightly. Use the column for the standard on your drawing or purchase order.
| Element | 42CrMo4 EN 10083-3 | 709M40 (EN19) BS 970-1:1983 | 4140 SAE J404 | SCM440 JIS G4053 |
|---|---|---|---|---|
| C % | 0.38–0.45 | 0.36–0.44 | 0.38–0.43 | 0.38–0.43 |
| Si % | ≤ 0.40 | 0.10–0.35 | 0.15–0.35 | 0.15–0.35 |
| Mn % | 0.60–0.90 | 0.70–1.00 | 0.75–1.00 | 0.60–0.90 |
| P % | ≤ 0.025 | ≤ 0.05 | ≤ 0.035 | ≤ 0.03 |
| S % | ≤ 0.035 | ≤ 0.05 | ≤ 0.04 | ≤ 0.03 |
| Cr % | 0.90–1.20 | 0.90–1.20 | 0.80–1.10 | 0.90–1.20 |
| Mo % | 0.15–0.30 | 0.25–0.35 | 0.15–0.25 | 0.15–0.30 |
EN19 Mechanical Properties
| Condition | Tensile, MPa | Yield min, MPa | Elongation min, % | Hardness |
|---|---|---|---|---|
| QT, d <= 16 mm (42CrMo4) | 1100 – 1300 | 900 | 10 | – |
| QT, 16 < d <= 40 mm (42CrMo4) | 1000 – 1200 | 750 | 11 | – |
| QT, 40 < d <= 100 mm (42CrMo4) | 900 – 1100 | 650 | 12 | – |
Delivery Condition and Heat Treatment
Typical practice is to harden from about 830–860 °C, quench in oil, then temper. The tempering temperature sets the final strength: tempering lower gives higher strength, tempering higher gives more toughness. In quenched and tempered condition, a bar up to Ø 16 mm reaches 1,100–1,300 MPa tensile and 900 MPa minimum yield. A bar of Ø 40–100 mm reaches 900–1,100 MPa and 650 MPa minimum yield, because the core cools more slowly in larger sections.
If you want to skip your own heat treatment, we supply EN19 pre-hardened to 28–34 HRC (+QT). It machines to final size and goes into service without a further hardening step. In the annealed condition EN19 machines more easily, so heavy roughing is best done before hardening.
EN19 is not a weld-friendly grade. The carbon and alloy content make the heat-affected zone hard and crack-prone, so welding needs preheat and a post-weld stress relief. If the part must be welded, SAE 4130 is the more weldable alternative.
What We Supply EN19 In
Round BarsRolled Ø 16–500 mm · Forged to order↗
Bright BarsRound Ø 8–160 mm · Hex 18–50 mm AF↗
Forged BarsRound Ø 250–1,030 mm · Square 280–800 mm↗
ShaftsDiameter Ø 25–500 mm · Length 300–6,000 mm↗
Forgings & Special ComponentsRound Ø 250–1,030 mm · Square 280–800 mm↗
RCSRound-corner square 20–75 mm↗
Where EN19 Is Used
Industries: Automotive, Oil and gas, Industrial machinery, Mining and construction equipment, Defence and aerospace ground equipment, Fasteners, Tooling
Compare EN19 with Similar Grades
| EN19 | EN24 | SAE 4130 | SAE 4145 | |
|---|---|---|---|---|
| Why consider it | This grade | Nickel-bearing, tougher at higher strength | Lower carbon, more weldable | Slightly higher carbon |
| C % | 0.38–0.45 | 0.36–0.44 | 0.28–0.33 | 0.43–0.48 |
| Si % | ≤ 0.4 | 0.1–0.35 | 0.15–0.35 | 0.15–0.35 |
| Mn % | 0.6–0.9 | 0.45–0.7 | 0.4–0.6 | 0.75–1 |
| Cr % | 0.9–1.2 | 1–1.4 | 0.8–1.1 | 0.8–1.1 |
| Mo % | 0.15–0.3 | 0.2–0.35 | 0.15–0.25 | 0.15–0.25 |
| Ni % | – | 1.3–1.8 | – | – |
EN19 Questions
What is the difference between EN19 and EN24?
EN24 contains nickel; EN19 does not. The nickel gives EN24 better toughness at higher strength and deeper hardening in large sections, and it costs more. For most shafts and gears in sizes up to about 100 mm, EN19 is the economical choice.
Is EN19 the same as 4140?
No, it is close but not identical. BS 970 709M40 (EN19) specifies molybdenum at 0.25–0.35% and chromium at 0.90–1.20%, while SAE 4140 specifies molybdenum at 0.15–0.25% and chromium at 0.80–1.10%. In practice 4140 is widely used where EN19 is specified and the reverse; tell us if your drawing needs the exact BS 970 chemistry.
Is EN19 the same as 42CrMo4?
42CrMo4 (1.7225) is a close equivalent, not an identical one. Its EN 10083-3 chemistry is carbon 0.38–0.45%, chromium 0.90–1.20% and molybdenum 0.15–0.30%, a wider molybdenum band than 709M40. Most Indian and European buyers treat the two as interchangeable.
What hardness does EN19 reach after heat treatment?
It depends on the tempering temperature and bar diameter. Our pre-hardened bars are supplied at 28–34 HRC, and fully hardened EN19 can reach well above 50 HRC before tempering. Tell us the hardness or tensile strength you need and we supply it in that condition.
Can EN19 be welded?
It can be, but only with care. Preheat before welding and stress-relieve afterwards to avoid cracking in the hard heat-affected zone. If welding is a core part of your process, consider SAE 4130, which has lower carbon.
What is the minimum order for EN19 bright bars?
3 tonnes, flexible depending on grade, size and your situation. Round bars, forged bars and shafts are supplied on request; send us your size, condition and quantity.
What is EN19 equivalent to?
EN19 is the same grade as Old BS EN EN19, BS 970 709M40, UNI 42CrMo4, UNE 42CrMo4. Close equivalents are Old BS EN EN19A, AISI/SAE 4140, UNS G41400, EN 42CrMo4, DIN W.Nr. 1.7225, JIS SCM440.
In which forms do you supply EN19?
OneKaizen supplies EN19 as Round Bars, Bright Bars, Forged Bars, Shafts, Forgings & Special Components, RCS, delivered across India and exported to buyers abroad.
Do you supply EN19 with a mill test certificate?
Yes. Every lot ships with an EN 10204 3.1 mill test certificate showing chemistry and mechanical properties, traceable to the heat number.
Data compiled by the OneKaizen metallurgy team from the standards named above. Updated 26 October 2026. Equivalents are nearest matches; confirm critical substitutions against the governing standard and mill certificate.