Steel 20MoCrS4 +U (Hot rolled)
Finish state
EN 20MoCrS4
Cheapest hot-rolled bar supply when the customer normalizes or anneals in-house before machining.
Values for the +U condition
Other 20MoCrS4 tempers and conditions
20MoCrS4 is listed in 9 conditions; see the grade overview at 20MoCrS4.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Softest supply state — use for deep cold forming/cold extrusion of blanks or for heavy drilling/broaching before carburizing. | 330 | 540 | 23 | 165 HB | — |
Treated for shearability | Choose when bar is cold-sheared into slugs for cold/warm forging before carburizing. | 350 | 560 | 20 | 170 HB | 8 % IACS |
Treated to ferrite-pearlite structure and hardness range | Standard hot-rolled bar condition giving a uniform F-P microstructure and predictable, repeatable turning/hobbing behaviour before carburizing. | 400 | 620 | 18 | 178 HB | — |
Treated to a specified hardness range | Pick when only a hardness window (not the microstructure) must be guaranteed for stable machining. | 410 | 600 | 18 | 10 HRC | 8 % IACS |
+UThis page Hot rolled | Cheapest hot-rolled bar supply when the customer normalizes or anneals in-house before machining. | 420 | 660 | 17 | 12 HRC | 8 % IACS |
Guaranteed hardenability (Jominy band) / hardened condition | Order +H when the Jominy end-quench band must be certified so case/core hardness after carburizing-quenching is reproducible on high-volume gear and shaft parts. | 430 | 620 | 17 | 44 HRC | 8 % IACS |
+AC+CDefault Spheroidize annealed and cold drawn | The workhorse condition for automatic-lathe/Swiss turning: tight tolerance bright bar with good chip control and enough strength for handling before carburizing. | 500 | 600 | 10 | 185 HB | — |
Cold drawn | Cold-drawn bright bar without prior spheroidizing — cheaper, slightly stronger and harder than +AC+C but less suited to cold heading. | 570 | 680 | 8 | 14 HRC | 8 % IACS |
Case hardened | Final in-service condition of the finished part: hard wear-resistant case over a tough Mo-Cr alloyed core. | 750 | 1,050 | 10 | 60 HRC | — |
What is 20MoCrS4 +U?
20MoCrS4 +U is 20MoCrS4 supplied in the +U condition — cheapest hot-rolled bar supply when the customer normalizes or anneals in-house before machining. 20MoCrS4 +U has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 53% of steel grades. Elongation at break is 17% and the elastic modulus is 210 GPa (30.5 Msi). 20MoCrS4 +U has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). +AC+C is the default condition FabDigit quotes; +U is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 78% of steel grades
20MoCrS4 +U properties
Typical room-temperature values for 20MoCrS4 +U; 23 are specific to this condition. Other listed values are 20MoCrS4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
20MoCrS4 +U has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
20MoCrS4 +U has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 53% of steel grades. Elongation at break is 17% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20MoCrS4 +U is rated for continuous service to 200°C (392 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
20MoCrS4 +U conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 20MoCrS4 +U takes about 26 MJ of energy and emits 1.9 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability8
20MoCrS4 +U's machinability is good (58/100, better than 75% of steel grades); weldability poor (32/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20MoCrS4 +U
Is 20MoCrS4 easy to machine?
Excellent for CNC/cam automatics in +AC+C: MnS inclusions break chips; carbide inserts at 150–220 m/min turning, coolant optional — expect ~15–25 % better tool life than sulfur-free 20MoCr4.
Can 20MoCrS4 be welded?
Poor: CEV ≈ 0.5–0.6 plus 0.02–0.04 % S causes hot-cracking risk; if unavoidable use low-hydrogen consumables, 200–300 °C preheat, immediate stress relief, and never weld carburized surfaces.
Can 20MoCrS4 be formed, bent or molded?
Cold heading/extrusion only from the +AC (spheroidized) state with phosphate-soap lubrication; hot forge 1100–850 °C then anneal, avoid heavy transverse cold bending because sulfides reduce transverse ductility.
What surface finishes work on 20MoCrS4?
Not anodizable; protect with phosphating + oil, black oxide, or Zn/Zn-Ni plating (bake 190–220 °C for hydrogen de-embrittlement after case hardening); ground and honed case surfaces polish to a functional but not mirror finish.
20MoCrS4 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 | 0.17 – 0.23 | 0.2 |
| Simax only | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| Pmax only | ≤ 0.03 | 0.02 |
| Sdeliberately added for machinability (resulfurized) | 0.02 – 0.04 | 0.03 |
| Cr | 0.3 – 0.6 | 0.45 |
| Mo | 0.4 – 0.5 | 0.45 |
| Fe | balance | — |
20MoCrS4 +U — frequently asked
What is 20MoCrS4 +U used for?
20MoCrS4 +U is typically used for mass-produced carburized gears, shafts on CNC turning centers and small automotive driveline parts. In short: free-machining 20MoCr4; 15–25 % longer tool life; poor weldability.
What is the yield strength of 20MoCrS4 +U?
20MoCrS4 +U has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 20MoCrS4 +U easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Excellent for CNC/cam automatics in +AC+C: MnS inclusions break chips; carbide inserts at 150–220 m/min turning, coolant optional — expect ~15–25 % better tool life than sulfur-free 20MoCr4.
Can 20MoCrS4 +U be welded?
Not readily — weldability is rated poor (32/100). Poor: CEV ≈ 0.5–0.6 plus 0.02–0.04 % S causes hot-cracking risk; if unavoidable use low-hydrogen consumables, 200–300 °C preheat, immediate stress relief, and never weld carburized surfaces.
What surface finishes work on 20MoCrS4 +U?
Not anodizable; protect with phosphating + oil, black oxide, or Zn/Zn-Ni plating (bake 190–220 °C for hydrogen de-embrittlement after case hardening); ground and honed case surfaces polish to a functional but not mirror finish.
Can 20MoCrS4 +U be formed, bent or molded?
Cold heading/extrusion only from the +AC (spheroidized) state with phosphate-soap lubrication; hot forge 1100–850 °C then anneal, avoid heavy transverse cold bending because sulfides reduce transverse ductility.
What is the maximum service temperature of 20MoCrS4 +U?
20MoCrS4 +U is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20MoCrS4 +AC+C and 20MoCrS4 CHQT?
+AC+C is the default condition — the workhorse condition for automatic-lathe/Swiss turning: tight tolerance bright bar with good chip control and enough strength for handling before carburizing. CHQT: final in-service condition of the finished part: hard wear-resistant case over a tough Mo-Cr alloyed core. Yield strength is 500 MPa in +AC+C versus 750 MPa in CHQT.
Sources
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- EN 10277 — Bright steel products: technical delivery conditions — CEN (2018)
- Stahlschlüssel / Key to Steel — Verlag Stahlschlüssel Wegst (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Case-hardening steel 20MoCr4 / 20MoCrS4 data sheet — Deutsche Edelstahlwerke / Ovako (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.