Steel S35C QT 25-30 HRC
Hardness band
JIS S35C
QT 25-30 HRC = q&T to 25–30 HRC
Choose for higher-loaded shafts and gears in small sections where full hardenability of 0.35 %C is available.
Values for the QT 25-30 HRC condition
Other S35C tempers and conditions
S35C is listed in 8 conditions; see the grade overview at S35C.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize Annealed | Spheroidized carbides for cold heading of bolts and cold extrusion blanks. | 270 | 480 | 33 | 140 HB | 10 % IACS |
Solution annealed | Softest condition — choose for deep machining, cold forming or before further heat treatment. | 280 | 500 | 30 | 143 HB | — |
Hot rolled | Cheapest stock form for non-critical shafts and weldments where machining allowance removes scale. | 300 | 550 | 22 | 160 HB | — |
NDefault Normalized | Standard stocked condition — uniform fine pearlitic structure with balanced strength, toughness and machinability. | 340 | 560 | 25 | 170 HB | — |
Quenched and tempered | Pick the water quenched and high-tempered condition (≈170–235 HB) for shafts and bolts needing 420 MPa yield with retained toughness and 22% elongation. | 420 | 640 | 22 | 13 HRC | — |
Induction hardened | Use where a wear-resistant, compressively stressed surface is needed on a tough shaft core. | 420 | 640 | 20 | 52 HRC | — |
Cold drawn | Pick for tight tolerance, smooth surface shafting used near as-supplied size with higher yield strength. | 530 | 620 | 12 | 185 HB | — |
QT 25-30 HRCThis page Q&T to 25–30 HRC | Choose for higher-loaded shafts and gears in small sections where full hardenability of 0.35 %C is available. | 740 | 900 | 17 | 28 HRC | — |
What is S35C QT 25-30 HRC?
S35C QT 25-30 HRC is S35C heat treated to QT 25-30 HRC — choose for higher-loaded shafts and gears in small sections where full hardenability of 0.35 %C is available. S35C QT 25-30 HRC has a yield strength of 740 MPa (107 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 83% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi). S35C QT 25-30 HRC 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). N is the default condition FabDigit quotes; QT 25-30 HRC is available on request or by drawing note.
Advantages
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
- High strength — 740 MPa (107 ksi), better than 83% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
Limitations
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
S35C QT 25-30 HRC properties
Typical room-temperature values for S35C QT 25-30 HRC; 12 are specific to this condition. Other listed values are S35C reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S35C QT 25-30 HRC 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).
Mechanical15
S35C QT 25-30 HRC has a yield strength of 740 MPa (107 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 83% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
S35C QT 25-30 HRC is rated for continuous service to 400°C (752 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
S35C QT 25-30 HRC conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of S35C QT 25-30 HRC takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
S35C QT 25-30 HRC's machinability is fair (47/100, worse than 58% of steel grades); weldability fair (45/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S35C QT 25-30 HRC
Is S35C easy to machine?
Machines readily at ~65 % of AISI 1212; normalized or 180–200 HB Q&T structure gives the best chip control, annealed material tends to smear.
Can S35C be welded?
Weldable by SMAW/GMAW with low-hydrogen consumables; preheat 100–200 °C above ~20 mm thickness and PWHT/slow cool to avoid HAZ martensite cracking.
Can S35C be formed, bent or molded?
Hot forges well at 1050–1200 °C; cold bending limited — use spheroidize-annealed stock for cold heading and allow generous bend radii.
What surface finishes work on S35C?
No corrosion resistance of its own — protect with phosphating, black oxide, zinc/Zn-Ni plating, hard chrome on shafts, or paint; takes a good polish up to a fine ground/lapped finish.
S35C 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 – 0.38 | 0.35 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | — |
| S | ≤ 0.04 | — |
| Curesidual, max | ≤ 0.3 | — |
| Niresidual, max | ≤ 0.2 | — |
| Crresidual, max; Ni+Cr ≤ 0.35 | ≤ 0.2 | — |
| Fe | balance | — |
S35C QT 25-30 HRC — frequently asked
What is S35C QT 25-30 HRC used for?
S35C QT 25-30 HRC is typically used for shafts, bolts, forged components and gears. In short: forging-grade medium carbon; stronger than S30C; induction-hardenable shaft steel.
What is the yield strength of S35C QT 25-30 HRC?
S35C QT 25-30 HRC has a typical yield strength of 740 MPa (107 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 83% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is S35C QT 25-30 HRC easy to machine?
Reasonably — machinability is rated fair (47/100, worse than 58% of steel grades). Machines readily at ~65 % of AISI 1212; normalized or 180–200 HB Q&T structure gives the best chip control, annealed material tends to smear.
Can S35C QT 25-30 HRC be welded?
With care — weldability is rated fair (45/100). Weldable by SMAW/GMAW with low-hydrogen consumables; preheat 100–200 °C above ~20 mm thickness and PWHT/slow cool to avoid HAZ martensite cracking.
What surface finishes work on S35C QT 25-30 HRC?
No corrosion resistance of its own — protect with phosphating, black oxide, zinc/Zn-Ni plating, hard chrome on shafts, or paint; takes a good polish up to a fine ground/lapped finish.
Can S35C QT 25-30 HRC be formed, bent or molded?
Hot forges well at 1050–1200 °C; cold bending limited — use spheroidize-annealed stock for cold heading and allow generous bend radii.
What is the maximum service temperature of S35C QT 25-30 HRC?
S35C QT 25-30 HRC is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S35C-N and S35C-CD?
N is the default condition — standard stocked condition — uniform fine pearlitic structure with balanced strength, toughness and machinability. CD: pick for tight tolerance, smooth surface shafting used near as-supplied size with higher yield strength. Yield strength is 340 MPa in N versus 530 MPa in CD.
Sources
- JIS G 4051 — Carbon steels for machine structural use — JSA (2016)
- GB/T 699 — Quality carbon structural steels (35 ) — SAC (2015)
- SAE J403 / ASTM A29 — Carbon steel bars (1035) — SAE / ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- Mysteel / SMM (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.