Steel SCM435 Q&T 34-38 HRC
Hardness band
JIS SCM435
Q&T 34-38 HRC = tempered to high hardness
Higher-strength bracket for heavily loaded gears, spindles and class 10.9 fasteners where some toughness can be traded away.
Values for the Q&T 34-38 HRC condition
Other SCM435 tempers and conditions
SCM435 is listed in 10 conditions; see the grade overview at SCM435.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize Annealed | Standard condition for SCM435 cold-heading wire used to make class 10.9/12.9 bolts. | 340 | 560 | 28 | 160 HB | 8.2 % IACS |
full/soft anneal | Softest machining condition and the usual delivery state for parts to be finish-hardened later. | 380 | 600 | 25 | 175 HB | — |
HRDefault Hot rolled | Default stock form for bar and plate that will be machined and then heat treated by the user. | 450 | 700 | 20 | 207 HB | — |
860–880 °C air cooled | Use to refine grain and homogenize forgings/weldments before final Q&T or for moderately loaded parts. | 510 | 760 | 20 | 217 HB | — |
Cold rolled | Choose for thin strip stampings and blanks that need tight thickness tolerance and a smooth surface before hardening. | 600 | 760 | 12 | 20 HRC | 7.8 % IACS |
Cold drawn | Pick for straight, size-accurate bright bar used directly for shafts and studs with light machining. | 660 | 800 | 12 | 240 HB | — |
Tempered to medium hardness | Balanced strength/toughness bracket for general machined shafts, couplings and pressure components. | 820 | 960 | 18 | 30 HRC | — |
Quenched and tempered | Standard JIS G4053 delivery condition for shafts, gears and high-tensile bolts needing ≥930 MPa with good toughness. | 850 | 1,000 | 17 | 31 HRC | — |
Q&T 34-38 HRCThis page Tempered to high hardness | Higher-strength bracket for heavily loaded gears, spindles and class 10.9 fasteners where some toughness can be traded away. | 1,030 | 1,150 | 14 | 36 HRC | — |
Low-temper high strength | Maximum practical strength level for SCM435 fasteners and tooling; watch hydrogen embrittlement during plating. | 1,150 | 1,300 | 12 | 42 HRC | — |
What is SCM435 Q&T 34-38 HRC?
SCM435 Q&T 34-38 HRC is SCM435 heat treated to Q&T 34-38 HRC — higher-strength bracket for heavily loaded gears, spindles and class 10.9 fasteners where some toughness can be traded away. SCM435 Q&T 34-38 HRC has a yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 93% of steel grades. Elongation at break is 14% and the elastic modulus is 207 GPa (30 Msi). SCM435 Q&T 34-38 HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F). HR is the default condition FabDigit quotes; Q&T 34-38 HRC is available on request or by drawing note.
Advantages
- High strength — 1,030 MPa (149 ksi), better than 93% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Difficult to machine — 38/100, worse than 80% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
SCM435 Q&T 34-38 HRC properties
Typical room-temperature values for SCM435 Q&T 34-38 HRC; 12 are specific to this condition. Other listed values are SCM435 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SCM435 Q&T 34-38 HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F).
Mechanical16
SCM435 Q&T 34-38 HRC has a yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 93% of steel grades. Elongation at break is 14% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
SCM435 Q&T 34-38 HRC is rated for continuous service to 400°C (752 °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
SCM435 Q&T 34-38 HRC conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of SCM435 Q&T 34-38 HRC takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 25%.
Manufacturability6
SCM435 Q&T 34-38 HRC's machinability is fair (38/100, worse than 80% of steel grades); weldability fair (45/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SCM435 Q&T 34-38 HRC
Is SCM435 easy to machine?
Machine in the annealed or normalized state (≈180–230 HB); above 32 HRC use coated carbide, rigid setups and reduced speeds, and finish-grind after hardening.
Can SCM435 be welded?
Weldable with low-hydrogen consumables but requires 200–300 °C preheat, controlled interpass and 600–680 °C PWHT to avoid HAZ cracking.
Can SCM435 be formed, bent or molded?
Hot forge at 1100–1200 °C with slow cooling; cold heading only from spheroidize-annealed CHQ wire, followed by quench and temper.
What surface finishes work on SCM435?
No corrosion resistance of its own — zinc, zinc-nickel, Dacromet, phosphate-and-oil, nitriding or hard chrome are standard; bake after electroplating above 1000 MPa to relieve hydrogen embrittlement.
SCM435 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 |
| Mo | 0.15 – 0.3 | 0.22 |
| Niresidual max | ≤ 0.25 | |
| Curesidual max | ≤ 0.3 | |
| Fe | balance |
SCM435 Q&T 34-38 HRC — frequently asked
What is SCM435 Q&T 34-38 HRC used for?
SCM435 Q&T 34-38 HRC is typically used for drive shafts, industrial bolts and crankshafts. In short: workhorse Cr-Mo bar.
What is the yield strength of SCM435 Q&T 34-38 HRC?
SCM435 Q&T 34-38 HRC has a typical yield strength of 1,030 MPa (149 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 93% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is SCM435 Q&T 34-38 HRC easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Machine in the annealed or normalized state (≈180–230 HB); above 32 HRC use coated carbide, rigid setups and reduced speeds, and finish-grind after hardening.
Can SCM435 Q&T 34-38 HRC be welded?
With care — weldability is rated fair (45/100). Weldable with low-hydrogen consumables but requires 200–300 °C preheat, controlled interpass and 600–680 °C PWHT to avoid HAZ cracking.
What surface finishes work on SCM435 Q&T 34-38 HRC?
No corrosion resistance of its own — zinc, zinc-nickel, Dacromet, phosphate-and-oil, nitriding or hard chrome are standard; bake after electroplating above 1000 MPa to relieve hydrogen embrittlement.
Can SCM435 Q&T 34-38 HRC be formed, bent or molded?
Hot forge at 1100–1200 °C with slow cooling; cold heading only from spheroidize-annealed CHQ wire, followed by quench and temper.
What is the maximum service temperature of SCM435 Q&T 34-38 HRC?
SCM435 Q&T 34-38 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 SCM435-HR and SCM435-CD?
HR is the default condition — default stock form for bar and plate that will be machined and then heat treated by the user. CD: pick for straight, size-accurate bright bar used directly for shafts and studs with light machining. Yield strength is 450 MPa in HR versus 660 MPa in CD.
Can FabDigit make parts in SCM435 Q&T 34-38 HRC?
Yes — SCM435 Q&T 34-38 HRC 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
- JIS G 4053 — Low-alloyed steels for machine structural use — JSA (2016)
- GB/T 3077 — Alloy structural steels (35CrMo) — 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)
- SAE J404 — Chemical Compositions of SAE Alloy Steels (4135) — SAE International (2009)
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.