Steel SCr435-QT (Quenched and tempered)
Heat-treated state · default condition
JIS SCr435
Standard commercial delivery condition: oil quench ~860 °C, temper 530–630 °C, for shafts, axles and bolts.
Values for the QT condition
Other SCr435 tempers and conditions
SCr435 is listed in 10 conditions; see the grade overview at SCr435.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Pick for maximum machinability, cold forging or deep boring before hardening. | 350 | 600 | 25 | 197 HB | — |
Hot rolled | Cheapest mill condition for stock that will be re-heat-treated by the fabricator. | 420 | 700 | 20 | 207 HB | — |
Normalized | Uniform fine grain for forgings before final machining or hardening; moderate strength as-supplied. | 470 | 760 | 20 | 20 HRC | 8 % IACS |
Cold drawn | Use for close-tolerance, bright-finish shafting where no further heat treatment is planned. | 640 | 780 | 12 | 235 HB | — |
high-temper (tough) condition | Choose when toughness and machinability after heat treatment matter more than peak strength. | 750 | 900 | 19 | 27 HRC | 7.8 % IACS |
QTDefaultThis page Quenched and tempered | Standard commercial delivery condition: oil quench ~860 °C, temper 530–630 °C, for shafts, axles and bolts. | 830 | 980 | 17 | 31 HRC | — |
standard shafting hardness | Most common ordered hardness band for transmission shafts and connecting rods. | 830 | 980 | 17 | 30 HRC | 7.8 % IACS |
Induction hardened | Bearing journals and gear teeth needing a 50+ HRC wear surface over a tough tempered core. | 830 | 980 | 15 | 54 HRC | 7.5 % IACS |
higher-strength condition | For higher-loaded shafts and fasteners where some toughness may be traded for strength. | 950 | 1,100 | 15 | 34 HRC | — |
low-temper high-strength condition | Thin sections needing high strength and wear resistance; machine before hardening. | 1,150 | 1,300 | 12 | 40 HRC | — |
What is SCr435-QT?
SCr435-QT is SCr435 heat treated to QT — standard commercial delivery condition: oil quench ~860 °C, temper 530–630 °C, for shafts, axles and bolts. SCr435-QT has a yield strength of 830 MPa (120 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 87% of steel grades. Elongation at break is 17% and the elastic modulus is 206 GPa (29.9 Msi). SCr435-QT 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).
Advantages
- High strength — 830 MPa (120 ksi), better than 87% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
SCr435-QT properties
Typical room-temperature values for SCr435-QT; 13 are specific to this condition. Other listed values are SCr435 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SCr435-QT 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).
Mechanical16
SCr435-QT has a yield strength of 830 MPa (120 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 87% of steel grades. Elongation at break is 17% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
SCr435-QT is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
SCr435-QT 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 SCr435-QT takes about 30 MJ of energy and emits 2.1 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 25%.
Manufacturability7
SCr435-QT's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (40/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SCr435-QT
Is SCr435 easy to machine?
Machine in the annealed or normalized state (≈55–65 % of AISI 1212); above 32 HRC use carbide with rigid setups and finish-grind after hardening.
Can SCr435 be welded?
Restricted weldability — preheat 200–300 °C, low-hydrogen consumables, and temper/stress-relieve at 550–650 °C immediately after welding to avoid HAZ cracking.
Can SCr435 be formed, bent or molded?
Hot forge 1100–1200 °C and cool slowly or normalize; cold heading and bending are practical only in the spheroidize-annealed condition.
What surface finishes work on SCr435?
No natural corrosion protection — specify black oxide, phosphate + oil, zinc or hard-chrome plating; grind and polish easily for shaft seal surfaces.
SCr435 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 | 0.33 – 0.38 | 0.35 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.6 – 0.85 | 0.72 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Cr | 0.9 – 1.2 | 1.05 |
| Niresidual, max | ≤ 0.25 | — |
| Curesidual, max | ≤ 0.3 | — |
| Fe | balance | — |
SCr435-QT — frequently asked
What is SCr435-QT used for?
SCr435-QT is typically used for shafts, gears and bolts. In short: stronger than SCr430; wide Q&T hardness range; induction-hardenable shaft steel.
What is the yield strength of SCr435-QT?
SCr435-QT has a typical yield strength of 830 MPa (120 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 87% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is SCr435-QT easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machine in the annealed or normalized state (≈55–65 % of AISI 1212); above 32 HRC use carbide with rigid setups and finish-grind after hardening.
Can SCr435-QT be welded?
With care — weldability is rated fair (40/100). Restricted weldability — preheat 200–300 °C, low-hydrogen consumables, and temper/stress-relieve at 550–650 °C immediately after welding to avoid HAZ cracking.
What surface finishes work on SCr435-QT?
No natural corrosion protection — specify black oxide, phosphate + oil, zinc or hard-chrome plating; grind and polish easily for shaft seal surfaces.
Can SCr435-QT be formed, bent or molded?
Hot forge 1100–1200 °C and cool slowly or normalize; cold heading and bending are practical only in the spheroidize-annealed condition.
What is the maximum service temperature of SCr435-QT?
SCr435-QT 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 SCr435-QT and SCr435-A?
QT is the default condition — standard commercial delivery condition: oil quench ~860 °C, temper 530–630 °C, for shafts, axles and bolts. A: pick for maximum machinability, cold forging or deep boring before hardening. Yield strength is 830 MPa in QT versus 350 MPa in A.
Sources
- JIS G 4053 — Low-alloyed steels for machine structural use — JSA (2016)
- GB/T 3077 — Alloy structural steels (35Cr) — SAC (2015)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4 — Heat Treating — ASM International (1991)
- Machinery's Handbook, 31st ed. — Industrial Press (2020)
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.