Steel 4419-CH (Carburized and hardened)
Heat-treated state
AISI/SAE 4419 · UNS G44190
The service condition for gears, splines and pins: hard wear/pitting-resistant case with a tough ~25–35 HRC core.
Values for the CH condition
Other 4419 tempers and conditions
4419 is listed in 8 conditions; see the grade overview at 4419.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for cold forming/upsetting of fasteners and for the best tool life in heavy turning. | 300 | 470 | 30 | 135 HB | 8 % IACS |
ADefault Solution annealed | Standard stock condition for gear blanks and pins: softest, most machinable state prior to carburizing. | 330 | 500 | 25 | 145 HB | — |
H-band hardenability-guaranteed grade | Order the H grade when Jominy end-quench hardenability limits must be certified for repeatable case/core response in heat treatment. | 335 | 500 | 25 | 148 HB | 8 % IACS |
Hot rolled | Cheapest mill condition for parts that will be fully carburized and hardened after machining. | 350 | 540 | 23 | 160 HB | 8 % IACS |
Normalized | Use to homogenize forgings and refine grain before carburizing, giving more uniform case depth and less distortion. | 385 | 570 | 22 | 170 HB | 8 % IACS |
Cold drawn | Pick for close-tolerance, bright-finish bar where higher as-supplied strength and better chip control are wanted. | 500 | 600 | 14 | 180 HB | 8 % IACS |
direct quenched and tempered (core properties, ~30 HRC) | Use when the part is not carburized but needs a tough, medium-strength through-hardened body (small sections only). | 720 | 900 | 17 | 30 HRC | — |
CHThis page Carburized and hardened | The service condition for gears, splines and pins: hard wear/pitting-resistant case with a tough ~25–35 HRC core. | 750 | 1,000 | 12 | 60 HRC | — |
What is 4419-CH?
4419-CH is 4419 heat treated to CH — the service condition for gears, splines and pins: hard wear/pitting-resistant case with a tough ~25–35 HRC core. 4419-CH has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). 4419-CH 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). A is the default condition FabDigit quotes; CH 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
- Forms and bends easily — 62/100, better than 78% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
4419-CH properties
Typical room-temperature values for 4419-CH; 12 are specific to this condition. Other listed values are 4419 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4419-CH 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).
Mechanical13
4419-CH has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4419-CH 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 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
4419-CH conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 4419-CH takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
4419-CH's machinability is good (58/100, better than 75% of steel grades); weldability poor (15/100); formability good (62/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 4419-CH
Is 4419 easy to machine?
Machine in the annealed or normalized state (~65 % of 1212); sharp carbide or coated-carbide tools with flood coolant handle the gummy low-carbon chips, and all cutting must be finished before carburizing.
Can 4419 be welded?
Weldable with low-hydrogen consumables at ~150 °C preheat when in the soft condition; never weld after carburizing, and stress relieve/re-heat-treat welded assemblies before case hardening.
Can 4419 be formed, bent or molded?
Good cold and hot formability in the annealed/spheroidized state (forge 1150–1230 °C, finish above 900 °C); normalize after forging to refine grain for uniform case depth.
What surface finishes work on 4419?
No natural corrosion resistance — protect with oil, phosphate/black oxide, zinc or manganese phosphate; ground and superfinished case surfaces improve gear pitting life, and shot peening after carburizing raises bending fatigue.
4419 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 | 0.18 – 0.23 | 0.2 |
| Mn | 0.45 – 0.65 | 0.55 |
| Si | 0.15 – 0.35 | 0.25 |
| Mosole alloying addition; no Cr or Ni specified | 0.45 – 0.6 | 0.52 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
4419-CH — frequently asked
What is 4419-CH used for?
4419-CH is typically used for carburized gears, pins, camshafts and case-hardened shafts. In short: mo-only carburizing steel; tough core after case hardening; no Cr or Ni content.
What is the yield strength of 4419-CH?
4419-CH has a typical yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 4419-CH easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machine in the annealed or normalized state (~65 % of 1212); sharp carbide or coated-carbide tools with flood coolant handle the gummy low-carbon chips, and all cutting must be finished before carburizing.
Can 4419-CH be welded?
Not readily — weldability is rated poor (15/100). Weldable with low-hydrogen consumables at ~150 °C preheat when in the soft condition; never weld after carburizing, and stress relieve/re-heat-treat welded assemblies before case hardening.
What surface finishes work on 4419-CH?
No natural corrosion resistance — protect with oil, phosphate/black oxide, zinc or manganese phosphate; ground and superfinished case surfaces improve gear pitting life, and shot peening after carburizing raises bending fatigue.
Can 4419-CH be formed, bent or molded?
Good cold and hot formability in the annealed/spheroidized state (forge 1150–1230 °C, finish above 900 °C); normalize after forging to refine grain for uniform case depth.
What is the maximum service temperature of 4419-CH?
4419-CH 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 4419-A and 4419-CH?
A is the default condition — standard stock condition for gear blanks and pins: softest, most machinable state prior to carburizing. CH: the service condition for gears, splines and pins: hard wear/pitting-resistant case with a tough ~25–35 HRC core. Yield strength is 330 MPa in A versus 750 MPa in CH.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels — SAE International (2019)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
- ASTM A322 — Steel Bars, Alloy, Standard Grades — ASTM (2020)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4: Heat Treating (carburizing of Mo carburizing steels) — ASM International (1991)
- Machining Data Handbook — Metcut Research Associates (1980)
- MMPDS-style typical low-alloy steel elastic and thermal data — Battelle/FAA (2021)
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.