Steel 35CD4
EN 35CD4 · AISI/SAE 4135
35CD4 is the French AFNOR chromium-molybdenum steel equivalent to 34CrMo4 and AISI 4135, available annealed (+A), spheroidized (+AC), normalized, hot rolled, cold drawn, in +QT thin and heavy section conditions, in 22–26 to 32–36 HRC bands and nitrided.
Reference datasheet — 35CD4 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +QT condition
35CD4 tempers and conditions
35CD4 is supplied in 12 conditions, soft to hard. +QT is the default FabDigit quotes; the values on this page are for it.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose when the part is cold headed, cold extruded or deep machined before hardening. | 350 | 560 | 26 | 175 HB | 8 % IACS |
Annealed | Delivery condition for heavy machining, cold forming or before final heat treatment. | 400 | 620 | 22 | 200 HB | — |
Hot rolled | Cheapest mill condition; buy when the part will be fully heat treated after rough machining. | 440 | 700 | 18 | 17 HRC | 8 % IACS |
Normalized | Uniform fine-grain structure for weldments and parts that will not be quenched. | 480 | 750 | 18 | 20 HRC | — |
+QT heavy section | Use for large forgings and thick bar where hardenability limits the achievable strength. | 540 | 820 | 16 | 23 HRC | 8 % IACS |
Cold drawn | Pick for close-tolerance bright bar where the extra 15–20 % strength from drawing is enough. | 560 | 720 | 12 | 18 HRC | 8 % IACS |
Q&T to 22–26 HRC | Specify when H2S sulphide-stress-cracking rules cap hardness at 22 HRC max plus margin. | 620 | 800 | 18 | 24 HRC | 8 % IACS |
+QTDefault Quenched and tempered | Standard stocked condition for shafts, gears and highly loaded bolting; best strength/toughness balance. | 700 | 950 | 14 | 29 HRC | — |
Q&T + gas/plasma nitrided case | Choose for wear and fatigue-critical shafts; core keeps Q&T properties while the case reaches ~600 HV. | 700 | 950 | 14 | 56 HRC | 8 % IACS |
Q&T to 28–32 HRC | Common hardness call-out for machined shafts, couplings and pressure parts. | 780 | 960 | 15 | 30 HRC | 8 % IACS |
+QT thin section | Highest strength class of the grade, only achievable in small diameters and thin walls. | 850 | 1,080 | 12 | 35 HRC | 8 % IACS |
Q&T to 32–36 HRC | Upper practical hardness for this carbon level; use for wear-loaded shafts and high-strength fasteners. | 900 | 1,100 | 12 | 34 HRC | 8 % IACS |
What is 35CD4?
35CD4 is the French AFNOR chromium-molybdenum steel equivalent to 34CrMo4 and AISI 4135, available annealed (+A), spheroidized (+AC), normalized, hot rolled, cold drawn, in +QT thin and heavy section conditions, in 22–26 to 32–36 HRC bands and nitrided. Its slightly lower carbon than 42CD4 gives better weldability and cold-forming behaviour at medium strength, making it common for shafts, connecting rods and pressure-bearing structural parts in bar and tube. Default values are 700 MPa yield, 950 MPa tensile, 14 % elongation, 285 HB (29 HRC), service to 450 °C and a machinability score of 52. It has no corrosion resistance; step up to 42CD4 when higher strength in section is required. 35CD4 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). 35CD4 has a yield strength of 700 MPa (102 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 81% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
What is 35CD4 used for?
- shafts
- connecting rods
- structural parts
Advantages
- High service temperature — 450°C (842 °F), better than 86% of steel grades
- High strength — 700 MPa (102 ksi), better than 81% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited ductility — 14%, worse than 75% of steel grades
35CD4 properties
Typical room-temperature values for 35CD4-+QT; bars are the position among steel grades.
Physical3
35CD4 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).
Mechanical16
35CD4 has a yield strength of 700 MPa (102 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 81% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
35CD4 is rated for continuous service to 450°C (842 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
35CD4 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 35CD4 takes about 33 MJ of energy and emits 2.3 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 30%.
Manufacturability6
35CD4's machinability is fair (52/100, better than 52% of steel grades); weldability fair (45/100); formability poor (30/100).
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. 35CD4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 35CD4
Is 35CD4 easy to machine?
Machine in the annealed or ≤300 HB Q&T state with rigid setups, coated carbide, ~120–180 m/min turning; above 34 HRC switch to CBN or grinding.
Can 35CD4 be welded?
Weldable with low-hydrogen consumables but preheat 200–300 °C and stress relieve/temper at 550–650 °C after welding to avoid HAZ cracking; CE ≈ 0.75.
Can 35CD4 be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold form only in the +A/+AC spheroidized condition, otherwise bend hot or with generous radii.
35CD4 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 | 0.3 – 0.37 | 0.34 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P0.035 max in some product standards | ≤ 0.03 | |
| S≤0.005 for +S/free-cutting or ≤0.010 for clean variants | ≤ 0.04 | |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.15 – 0.3 | 0.22 |
| Fe | balance |
What surface finishes work on 35CD4?
No anodizing (ferrous); protect by zinc/Cr plating, manganese phosphate, black oxide, nitriding or paint — bake after plating to avoid hydrogen embrittlement above 30 HRC.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 35CD4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 35CD4 cost?
35CD4 is a budget-cost steel ($), cheaper than about 90% 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.
35CD4 — frequently asked
What is 35CD4 used for?
35CD4 is typically used for shafts, connecting rods and structural parts. In short: weldable Cr-Mo grade; lower carbon than 42CD4; good medium-strength shaft steel.
What is the yield strength of 35CD4?
35CD4 has a typical yield strength of 700 MPa (102 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 81% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is 35CD4 easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machine in the annealed or ≤300 HB Q&T state with rigid setups, coated carbide, ~120–180 m/min turning; above 34 HRC switch to CBN or grinding.
Can 35CD4 be welded?
With care — weldability is rated fair (45/100). Weldable with low-hydrogen consumables but preheat 200–300 °C and stress relieve/temper at 550–650 °C after welding to avoid HAZ cracking; CE ≈ 0.75.
What surface finishes work on 35CD4?
No anodizing (ferrous); protect by zinc/Cr plating, manganese phosphate, black oxide, nitriding or paint — bake after plating to avoid hydrogen embrittlement above 30 HRC.
Can 35CD4 be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold form only in the +A/+AC spheroidized condition, otherwise bend hot or with generous radii.
What is the maximum service temperature of 35CD4?
35CD4 is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 35CD4 +QT and 35CD4-HR?
+QT is the default condition — standard stocked condition for shafts, gears and highly loaded bolting; best strength/toughness balance. HR: cheapest mill condition; buy when the part will be fully heat treated after rough machining. Yield strength is 700 MPa in +QT versus 440 MPa in HR.
How much does 35CD4 cost?
35CD4 is a budget-cost steel ($), cheaper than about 90% 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.
Sources
- EN 10083-3 Steels for quenching and tempering — Alloy steels (34CrMo4 / 1.7220) — CEN (2006)
- NF A35-552 / AFNOR 35CD4 alloy structural steel — AFNOR (1993)
- GB/T 3077 (35CrMo) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 Machining / Vol.19 Fatigue and Fracture — ASM International (1996)
- 1.7220 / 34CrMo4 hot-rolled and Q&T bar datasheet — European long-products mill (2022)
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.