Steel 35CrMo
GB 35CrMo · AISI/SAE 4137
35CrMo is a chromium-molybdenum through-hardening alloy steel (4137 / SCM435 / 34CrMo4 / 1.7220) supplied hot rolled, cold drawn, annealed, normalized or quenched and tempered to 28–32, 34–38 or 40–44 HRC.
Values for the HR condition
35CrMo tempers and conditions
35CrMo is supplied in 11 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for cold heading/upsetting of high-strength bolts and for deep boring where the softest possible structure is wanted. | 380 | 620 | 27 | 170 HB | 8.1 % IACS |
full anneal (~840–860 °C, slow cool) | Pick for maximum machinability and dimensional stability before final heat treatment or for cold forming of blanks. | 420 | 680 | 24 | 197 HB | — |
HRDefault Hot rolled | Most stocked form: as-rolled round bar or plate destined for machining and subsequent quench-and-temper by the part maker. | 490 | 800 | 17 | 200 HB | — |
Normalized and tempered | Compromise condition for large forgings and pressure parts where oil quenching is impractical. | 600 | 850 | 19 | 24 HRC | 7.8 % IACS |
~870 °C, air cooled | Use for uniform fine-grain structure and moderate strength in large sections that will not be quenched. | 650 | 1,000 | 18 | 30 HRC | — |
Cold rolled | Thin strip/sheet condition for stamped and formed parts that will be hardened after blanking. | 660 | 830 | 11 | 23 HRC | 7.8 % IACS |
Cold drawn | Choose for close-tolerance, bright-surface bar used as-supplied in shafting and studs without further heat treatment. | 680 | 850 | 12 | 250 HB | — |
Tempered to ~950–1050 MPa | Tough general-purpose hardness band for machined shafts and NACE MR0175-conscious sour-service parts (≤22 HRC bands aside). | 860 | 1,000 | 16 | 30 HRC | — |
Quenched and tempered | Standard delivered/certified strength condition for shafts, connecting rods and grade 10.9/12.9 fasteners. | 880 | 1,030 | 14 | 33 HRC | — |
Tempered to ~1100–1250 MPa | Higher-strength band for gears, high-strength bolting and drill-string components where wear matters more than toughness. | 1,050 | 1,170 | 13 | 36 HRC | — |
Low-temperature temper, ~1300–1450 MPa | Maximum practical strength band for 35CrMo; use only where impact loading and hydrogen exposure are low. | 1,230 | 1,370 | 11 | 42 HRC | — |
What is 35CrMo?
35CrMo is a chromium-molybdenum through-hardening alloy steel (4137 / SCM435 / 34CrMo4 / 1.7220) supplied hot rolled, cold drawn, annealed, normalized or quenched and tempered to 28–32, 34–38 or 40–44 HRC. In the default Q&T condition it gives about 490 MPa yield, 800 MPa tensile, 17 % elongation and 200 HB, and is used for medium-high strength shafts, gears, connecting rods and bolts in bar and forged forms. Weldability is limited (200–300 °C preheat plus 600–680 °C PWHT), there is no corrosion resistance, and 42CrMo is the usual step up when higher hardenability or strength is required. 35CrMo has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). 35CrMo has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 61% of steel grades. Elongation at break is 17% and the elastic modulus is 210 GPa (30.5 Msi).
What is 35CrMo used for?
- Bolts
- Industrial drive shafts
- Crankshafts
Advantages
- High service temperature — 480°C (896 °F), better than 88% of steel grades
35CrMo properties
Typical room-temperature values for 35CrMo-HR; bars are the position among steel grades.
Physical3
35CrMo has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical14
35CrMo has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 61% of steel grades. Elongation at break is 17% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
35CrMo is rated for continuous service to 480°C (896 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
35CrMo 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 35CrMo takes about 34 MJ of energy and emits 2.3 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
35CrMo's machinability is good (55/100, better than 62% of steel grades); weldability fair (40/100); formability fair (40/100).
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. 35CrMo is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 35CrMo
Is 35CrMo easy to machine?
Machine in the annealed or ≤32 HRC condition with coated carbide, rigid setups and generous coolant; above 38 HRC expect ceramic/CBN finishing or grinding.
Can 35CrMo be welded?
Weldable with low-hydrogen electrodes but requires 200–300 °C preheat, matching Cr-Mo filler and 600–680 °C PWHT to avoid HAZ cold cracking.
Can 35CrMo be formed, bent or molded?
Hot forge at 1150–850 °C then normalize; cold forming only from spheroidize-annealed stock, with generous bend radii.
Manufacturability
The process limits FabDigit applies to 35CrMo. Every 35CrMo part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better55 / 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 | Fair40 / 100 |
|---|---|
| Weldability | Better40 / 100 |
35CrMo 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 | 0.32 – 0.4 | 0.35 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.4 – 0.7 | 0.55 |
| Cr | 0.8 – 1.1 | 0.95 |
| Mo | 0.15 – 0.25 | 0.2 |
| P≤ 0.025 for high-grade quality | ≤ 0.03 | 0.02 |
| S≤0.025 for high-grade quality | ≤ 0.03 | 0.02 |
| Niresidual | ≤ 0.3 | |
| Curesidual | ≤ 0.2 | |
| Fe | balance |
What surface finishes work on 35CrMo?
No natural corrosion protection — specify oiling, phosphate, zinc or Zn-Ni plating (bake to relieve hydrogen), QPQ/nitriding for wear, or paint.
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 35CrMo in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 35CrMo cost?
35CrMo 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.
35CrMo — frequently asked
What is 35CrMo used for?
35CrMo is typically used for bolts, industrial drive shafts and crankshafts. In short: premium Cr-Mo bar.
What is the yield strength of 35CrMo?
35CrMo has a typical yield strength of 490 MPa (71.1 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 61% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 35CrMo easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in the annealed or ≤32 HRC condition with coated carbide, rigid setups and generous coolant; above 38 HRC expect ceramic/CBN finishing or grinding.
Can 35CrMo be welded?
With care — weldability is rated fair (40/100). Weldable with low-hydrogen electrodes but requires 200–300 °C preheat, matching Cr-Mo filler and 600–680 °C PWHT to avoid HAZ cold cracking.
What surface finishes work on 35CrMo?
No natural corrosion protection — specify oiling, phosphate, zinc or Zn-Ni plating (bake to relieve hydrogen), QPQ/nitriding for wear, or paint.
Can 35CrMo be formed, bent or molded?
Hot forge at 1150–850 °C then normalize; cold forming only from spheroidize-annealed stock, with generous bend radii.
What is the maximum service temperature of 35CrMo?
35CrMo is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 35CrMo-HR and 35CrMo-CD?
HR is the default condition — most stocked form: as-rolled round bar or plate destined for machining and subsequent quench-and-temper by the part maker. CD: choose for close-tolerance, bright-surface bar used as-supplied in shafting and studs without further heat treatment. Yield strength is 490 MPa in HR versus 680 MPa in CD.
How much does 35CrMo cost?
35CrMo 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 35CrMo?
Yes — 35CrMo 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
- GB/T 699 / GB/T 702 (bar dimensions & delivery condition) — SAC (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (4130/4135/4140 data) — ASM International (1990)
- ASM Handbook Vol.16 — Machining (machinability ratings) — ASM International (1989)
- Cr-Mo structural steel 1.7220 / 34CrMo4 datasheet — Böhler / Deutsche Edelstahlwerke (2021)
- MMPDS-Handbook typical values for 4130/4140 low-alloy steel — Battelle / FAA (2021)
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.