Steel 20MoCrS4 CHQT
Heat-treated state
EN 20MoCrS4
CHQT = case hardened
Final in-service condition of the finished part: hard wear-resistant case over a tough Mo-Cr alloyed core.
Values for the CHQT 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 |
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 |
CHQTThis page 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 CHQT?
20MoCrS4 CHQT is 20MoCrS4 heat treated to CHQT — final in-service condition of the finished part: hard wear-resistant case over a tough Mo-Cr alloyed core. 20MoCrS4 CHQT has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 84% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi). 20MoCrS4 CHQT 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; CHQT is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High strength — 750 MPa (109 ksi), better than 84% of steel grades
Limitations
- Difficult to machine — 12/100, worse than 99% of steel grades
- Difficult to weld — 8/100, worse than 99% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 90% of steel grades
20MoCrS4 CHQT properties
Typical room-temperature values for 20MoCrS4 CHQT; 13 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 CHQT 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 CHQT has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 84% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20MoCrS4 CHQT is rated for continuous service to 180°C (356 °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 CHQT 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 CHQT 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 CHQT's machinability is not recommended (12/100, worse than 99% of steel grades); weldability not recommended (8/100); formability poor (32/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20MoCrS4 CHQT
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 CHQT — frequently asked
What is 20MoCrS4 CHQT used for?
20MoCrS4 CHQT 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 CHQT?
20MoCrS4 CHQT has a typical yield strength of 750 MPa (109 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 84% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 20MoCrS4 CHQT easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% 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 CHQT be welded?
Not readily — weldability is rated not recommended (8/100). 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 CHQT?
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 CHQT 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 CHQT?
20MoCrS4 CHQT is rated for continuous use to about 180°C (356 °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.