Steel SCM435 · heat-treated state
Steel SCM435-SA
Properties of the SA condition, compared with the other SCM435 tempers.
Standard condition for SCM435 cold-heading wire used to make class 10.9/12.9 bolts.
What is SCM435-SA?
SCM435-SA is SCM435 heat treated to SA — standard condition for SCM435 cold-heading wire used to make class 10.9/12.9 bolts. SCM435-SA has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 76% of steel grades. Elongation at break is 28% and the elastic modulus is 207 GPa (30 Msi). SCM435-SA 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; SA is available on request or by drawing note.
Advantages
- Easy to machine — 62/100, better than 89% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 88% of steel grades
- Forms and bends easily — 72/100, better than 88% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
SCM435-SA properties
Typical room-temperature values for SCM435-SA — 8 properties are specific to this condition; the rest are grade-level values shared by every SCM435 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
SCM435-SA 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-SA has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 76% of steel grades. Elongation at break is 28% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
SCM435-SA 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-SA conducts electricity at 7.8 % IACS, worse than 58% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of SCM435-SA 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-SA's machinability is good (62/100, better than 89% of steel grades); weldability fair (45/100); formability very good (72/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other SCM435 tempers and conditions
SCM435 is also supplied in 9 other conditions. The full side-by-side table is on the SCM435 overview.
- HRDefaultDefault stock form for bar and plate that will be machined and then heat treated by the user.450 MPa yield · 207 HB
- Q&T 40-44 HRCMaximum practical strength level for SCM435 fasteners and tooling; watch hydrogen embrittlement during plating.1,150 MPa yield · 42 HRC
- Q&T 34-38 HRCHigher-strength bracket for heavily loaded gears, spindles and class 10.9 fasteners where some toughness can be traded away.1,030 MPa yield · 36 HRC
- Q&TStandard JIS G4053 delivery condition for shafts, gears and high-tensile bolts needing ≥930 MPa with good toughness.850 MPa yield · 31 HRC
- Q&T 28-32 HRCBalanced strength/toughness bracket for general machined shafts, couplings and pressure components.820 MPa yield · 30 HRC
- CDPick for straight, size-accurate bright bar used directly for shafts and studs with light machining.660 MPa yield · 240 HB
- NormalizedUse to refine grain and homogenize forgings/weldments before final Q&T or for moderately loaded parts.510 MPa yield · 217 HB
- AnnealedSoftest machining condition and the usual delivery state for parts to be finish-hardened later.380 MPa yield · 175 HB
- SAStandard condition for SCM435 cold-heading wire used to make class 10.9/12.9 bolts.340 MPa yield · 160 HB
Working with SCM435-SA
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-SA — frequently asked
What is SCM435-SA used for?
SCM435-SA is typically used for drive shafts, industrial bolts and crankshafts. In short: workhorse Cr-Mo bar.
What is the yield strength of SCM435-SA?
SCM435-SA has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is SCM435-SA easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% 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-SA 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-SA?
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-SA 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-SA?
SCM435-SA 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-SA?
Yes — SCM435-SA is available for CNC machining and sheet metal with instant online pricing. 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.