Steel 4142-CR (Cold rolled)
Supply condition
AISI/SAE 4142 · UNS G41420 · EN 42CrMoS4
Cold-rolled flat/strip product with tight thickness tolerance and smooth surface; strength from cold work only.
Values for the CR condition
Other 4142 tempers and conditions
4142 is listed in 12 conditions; see the grade overview at 4142.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full/spheroidize annealed for machining and forming | Softest condition; pick for deep machining, cold forming or before final quench and temper. | 420 | 655 | 25 | 197 HB | 43 W/m·K |
HRDefault Hot rolled | Cheapest stock form for parts that will be heat treated or rough-machined after purchase. | 450 | 730 | 20 | 17 HRC | 7.8 % IACS |
Cold drawn | Straight, close-tolerance bright bar with better surface and chip control than hot rolled; use where no further heat treatment is planned. | 655 | 760 | 15 | 19 HRC | 7.8 % IACS |
CRThis page Cold rolled | Cold-rolled flat/strip product with tight thickness tolerance and smooth surface; strength from cold work only. | 670 | 790 | 12 | 21 HRC | 7.8 % IACS |
870 °C air cooled | Uniform fine-grain structure with medium-high strength; used as a pre-machining or as-supplied condition for forgings. | 670 | 1,035 | 17 | 32 HRC | 7.6 % IACS |
High-temper condition | Choose when hardness must be capped for stress-corrosion / sour-service or maximum toughness. | 720 | 830 | 20 | 24 HRC | 7.7 % IACS |
Tempered ~590 °C | Most commonly specified pre-hard bar hardness band: good strength with straightforward machining. | 880 | 1,000 | 17 | 30 HRC | 7.6 % IACS |
Quenched and tempered | Standard workhorse condition for shafts and machine parts needing high strength with usable toughness and machinability. | 960 | 1,080 | 16 | 32 HRC | — |
Tempered ~540 °C | Higher-strength shafting and tooling bodies where machining is still required after heat treatment. | 1,010 | 1,120 | 15 | 34 HRC | 7.5 % IACS |
Tempered ~480 °C | For wear-loaded pins, spindles and hydraulic components; machining now needs carbide tooling. | 1,200 | 1,320 | 13 | 40 HRC | — |
Low-temper high-hardness condition | Maximum practical strength/wear from 4142; accept low toughness and difficult machining (grind/EDM). | 1,450 | 1,600 | 10 | 48 HRC | — |
As-quenched | Intermediate in-process state only — must be tempered promptly to avoid quench cracking. | 1,650 | 2,050 | 2 | 56 HRC | 6.9 % IACS |
What is 4142-CR?
4142-CR is 4142 supplied in the CR condition — cold-rolled flat/strip product with tight thickness tolerance and smooth surface; strength from cold work only. 4142-CR has a yield strength of 670 MPa (97.2 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 80% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). 4142-CR 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). HR is the default condition FabDigit quotes; CR is available on request or by drawing note.
Advantages
- High strength — 670 MPa (97.2 ksi), better than 80% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
4142-CR properties
Typical room-temperature values for 4142-CR; 23 are specific to this condition. Other listed values are 4142 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4142-CR 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).
Mechanical17
4142-CR has a yield strength of 670 MPa (97.2 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 80% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4142-CR is rated for continuous service to 300°C (572 °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
4142-CR 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 4142-CR takes about 29 MJ of energy and emits 2 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 30%.
Manufacturability7
4142-CR's machinability is good (57/100, better than 71% of steel grades); weldability fair (38/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 4142-CR
Is 4142 easy to machine?
Machines best at 197–255 HB (annealed or 22–28 HRC); above ~35 HRC use coated carbide, rigid setups and reduced speeds, or grind.
Can 4142 be welded?
Weldable with low-hydrogen consumables but requires 200–320 °C preheat, controlled interpass and post-weld temper below the part's tempering temperature; avoid welding fully hardened sections.
Can 4142 be formed, bent or molded?
Cold form only in the annealed condition with generous radii; most shaping is done hot (1050–1200 °C forging) followed by normalize/anneal.
What surface finishes work on 4142?
No anodizing; protect with black oxide, manganese phosphate, zinc or hard chrome plating (bake to avoid hydrogen embrittlement above ~40 HRC) or nitriding for wear.
4142 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 | 0.4 – 0.45 | 0.42 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.15 – 0.35 | 0.25 |
| Cr | 0.8 – 1.1 | 0.95 |
| Mo | 0.15 – 0.25 | 0.2 |
| Pmax, SAE J404 | ≤ 0.04 | — |
| Smax, SAE J404 | ≤ 0.04 | — |
| Fe | balance | — |
4142-CR — frequently asked
What is 4142-CR used for?
4142-CR is typically used for shafts, industrial gears and drive shafts. In short: standard Cr-Mo machining bar.
What is the yield strength of 4142-CR?
4142-CR has a typical yield strength of 670 MPa (97.2 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 80% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is 4142-CR easy to machine?
Reasonably — machinability is rated good (57/100, better than 71% of steel grades). Machines best at 197–255 HB (annealed or 22–28 HRC); above ~35 HRC use coated carbide, rigid setups and reduced speeds, or grind.
Can 4142-CR be welded?
With care — weldability is rated fair (38/100). Weldable with low-hydrogen consumables but requires 200–320 °C preheat, controlled interpass and post-weld temper below the part's tempering temperature; avoid welding fully hardened sections.
What surface finishes work on 4142-CR?
No anodizing; protect with black oxide, manganese phosphate, zinc or hard chrome plating (bake to avoid hydrogen embrittlement above ~40 HRC) or nitriding for wear.
Can 4142-CR be formed, bent or molded?
Cold form only in the annealed condition with generous radii; most shaping is done hot (1050–1200 °C forging) followed by normalize/anneal.
What is the maximum service temperature of 4142-CR?
4142-CR is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 4142-HR and 4142-AQ?
HR is the default condition — cheapest stock form for parts that will be heat treated or rough-machined after purchase. AQ: intermediate in-process state only — must be tempered promptly to avoid quench cracking. Yield strength is 450 MPa in HR versus 1,650 MPa in AQ.
Can FabDigit make parts in 4142-CR?
Yes — 4142-CR 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
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4A — Steel Heat Treating Fundamentals and Processes — ASM International (2013)
- GB/T 3077 — Alloy Structural Steels (42CrMo) — SAC (2015)
- 4140/4142 alloy bar datasheets — Various bar producers/distributors (2023)
- 42CrMo — Mysteel / 1688 (2025)
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.