Steel EN19
BS EN19 · AISI/SAE 4140 · EN 42CrMo4 · GB 42CrMo
EN19 is a British Standard chromium-molybdenum through-hardening alloy steel, equivalent to AISI 4140, 42CrMo4 and 42CrMo, with hardenability and toughness suited to highly stressed components.
Values for the HR condition
EN19 tempers and conditions
EN19 is supplied in 12 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full/spheroidise annealed, softest condition | Pick for heavy machining, deep drilling or cold forming before final hardening. | 417 | 655 | 25.7 | 197 HB | — |
HRDefault Hot rolled | Cheapest stock form for parts that will be machined all over and then heat treated. | 520 | 800 | 18 | 22 HRC | — |
Cold rolled | Cold rolled flats/strip with good surface and tolerance, usually hardened after blanking. | 580 | 720 | 15 | 17 HRC | 7.8 % IACS |
Cold drawn | Close tolerance bright bar for shafts and studs machined without further heat treatment. | 635 | 745 | 14 | 223 HB | — |
air cooled from ~870 °C | Uniform fine-grain structure for weld fabrications and parts not needing full Q&T strength. | 655 | 1,020 | 17.7 | 31 HRC | — |
Condition T | Lowest BS 970 tempered class — maximum toughness and easiest machining of the Q&T range. | 720 | 920 | 16 | 28 HRC | 7.8 % IACS |
Quenched and tempered | Standard supplied condition for shafts and gear blanks — good strength/toughness balance and still machinable. | 830 | 1,000 | 14 | 30 HRC | — |
Condition V | Higher-strength shafting and high-tensile fasteners where toughness is still needed. | 900 | 1,075 | 14 | 34 HRC | 7.8 % IACS |
Solution heat treated (unstable) | For highly loaded axles, connecting rods and studs in moderate sections. | 990 | 1,150 | 13 | 36 HRC | 7.8 % IACS |
Condition X | High-strength class for smaller sections; toughness starts to fall away. | 1,050 | 1,225 | 12 | 40 HRC | 7.7 % IACS |
Condition Y | Very high strength small-section parts; grinding usually replaces turning. | 1,130 | 1,300 | 11 | 42 HRC | 7.7 % IACS |
Condition Z | Maximum-strength low-temper class for small highly stressed parts; low ductility and notch sensitivity. | 1,300 | 1,600 | 7 | 48 HRC | — |
Supply forms, finishes and certifications
Ways EN19 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
U | Condition U | Coating |
What is EN19?
EN19 is a British Standard chromium-molybdenum through-hardening alloy steel, equivalent to AISI 4140, 42CrMo4 and 42CrMo, with hardenability and toughness suited to highly stressed components. It is supplied hot-rolled, cold-rolled, cold-drawn, annealed, normalized and in the Q&T tempers T to Z; the default Q&T condition gives about 520 MPa yield, 800 MPa tensile, 18 % elongation and 235 HB (22 HRC). It needs preheat and post-weld tempering to weld safely, has no inherent corrosion resistance, and machinability (about 52) falls sharply above 40 HRC. Use 4340 where deeper hardenability is required. EN19 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F). EN19 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 67% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
What is EN19 used for?
- Drive shafts
- Crankshafts
- Industrial bolts
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
EN19 properties
Typical room-temperature values for EN19-HR; bars are the position among steel grades.
Physical3
EN19 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F).
Mechanical16
EN19 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 67% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
EN19 is rated for continuous service to 400°C (752 °F). It conducts heat at 42.6 W/m·K (24.6 BTU/hr·ft·°F), worse than 51% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
EN19 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of EN19 takes about 31 MJ of energy and emits 2.3 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
EN19's machinability is fair (52/100, better than 52% of steel grades); weldability fair (40/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. EN19 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with EN19
Is EN19 easy to machine?
Machine in the annealed or ≤32 HRC Q&T state with carbide at 100–160 m/min; above 40 HRC use CBN/ceramic or grind.
Can EN19 be welded?
Weldable with low-hydrogen consumables but requires 250–350 °C preheat, controlled interpass and immediate post-weld temper to avoid HAZ cracking.
Can EN19 be formed, bent or molded?
Hot forge 1100–1200 °C then normalise; cold bending only in the annealed condition with generous radii.
Manufacturability
The process limits FabDigit applies to EN19. Every EN19 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better52 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair35 / 100 |
|---|---|
| Weldability | Better40 / 100 |
EN19 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.36 – 0.44 | 0.4 |
| Si | 0.1 – 0.35 | 0.25 |
| Mn | 0.65 – 1 | 0.85 |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.25 – 0.35 | 0.3 |
| P | ≤ 0.04 | 0.02 |
| Smax; 709M40 fine-machining variants allow 0.015–0.035 | ≤ 0.04 | 0.02 |
| Fe | balance |
What surface finishes work on EN19?
No anodising — protect with zinc/manganese phosphate, black oxide, zinc or hard chrome plating, or nitride (up to ~600 HV) for wear surfaces.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel EN19 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does EN19 cost?
EN19 is a standard-cost steel ($$), cheaper than about 61% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
EN19 — frequently asked
What is EN19 used for?
EN19 is typically used for drive shafts, crankshafts and industrial bolts. In short: workhorse Q&T English bar.
What is the yield strength of EN19?
EN19 has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is EN19 easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machine in the annealed or ≤32 HRC Q&T state with carbide at 100–160 m/min; above 40 HRC use CBN/ceramic or grind.
Can EN19 be welded?
With care — weldability is rated fair (40/100). Weldable with low-hydrogen consumables but requires 250–350 °C preheat, controlled interpass and immediate post-weld temper to avoid HAZ cracking.
What surface finishes work on EN19?
No anodising — protect with zinc/manganese phosphate, black oxide, zinc or hard chrome plating, or nitride (up to ~600 HV) for wear surfaces.
Can EN19 be formed, bent or molded?
Hot forge 1100–1200 °C then normalise; cold bending only in the annealed condition with generous radii.
What is the maximum service temperature of EN19?
EN19 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between EN19-HR and EN19-Z?
HR is the default condition — cheapest stock form for parts that will be machined all over and then heat treated. Z: maximum-strength low-temper class for small highly stressed parts; low ductility and notch sensitivity. Yield strength is 520 MPa in HR versus 1,300 MPa in Z.
How much does EN19 cost?
EN19 is a standard-cost steel ($$), cheaper than about 61% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in EN19?
Yes — EN19 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- BS 970-1: Wrought steels — 709M40 (EN19) — BSI (1991)
- EN 10083-3: Quenched and tempered steels — 42CrMo4 — CEN (2006)
- GB/T 3077 — 42CrMo — SAC (2015)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels — ASM International (1990)
- ASM Machining Data Handbook — ASM International (1980)
- Alloy steel 42CrMo4/4140 bar datasheet — Böhler / Ovako (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.