Steel 35CD4 Nitrided
Finish state
EN 35CD4 · AISI/SAE 4135
Choose for wear and fatigue-critical shafts; core keeps Q&T properties while the case reaches ~600 HV.
Values for the Nitrided condition
Other 35CD4 tempers and conditions
35CD4 is listed in 12 conditions; see the grade overview at 35CD4.
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 | — |
NitridedThis page 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 Nitrided?
35CD4 Nitrided is 35CD4 supplied in the Nitrided condition — choose for wear and fatigue-critical shafts; core keeps Q&T properties while the case reaches ~600 HV. 35CD4 Nitrided 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). 35CD4 Nitrided 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). +QT is the default condition FabDigit quotes; Nitrided is available on request or by drawing note.
Advantages
- High service temperature — 500°C (932 °F), better than 90% 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
- Difficult to weld — 5/100, worse than 100% of steel grades
- Limited formability — 3/100, worse than 99% of steel grades
- Difficult to machine — 15/100, worse than 98% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
35CD4 Nitrided properties
Typical room-temperature values for 35CD4 Nitrided; 21 are specific to this condition. Other listed values are 35CD4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
35CD4 Nitrided 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 Nitrided 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 Nitrided is rated for continuous service to 500°C (932 °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 Nitrided conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of 35CD4 Nitrided 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 Nitrided's machinability is poor (15/100, worse than 98% of steel grades); weldability not recommended (5/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 35CD4 Nitrided
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.
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.
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 | — |
35CD4 Nitrided — frequently asked
What is 35CD4 Nitrided used for?
35CD4 Nitrided 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 Nitrided?
35CD4 Nitrided 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 Nitrided easy to machine?
Not especially — machinability is rated poor (15/100, worse than 98% 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 Nitrided be welded?
Not readily — weldability is rated not recommended (5/100). 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 Nitrided?
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 Nitrided 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 Nitrided?
35CD4 Nitrided is rated for continuous use to about 500°C (932 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.