Steel SCr430-A (Solution annealed)
Temper
JIS SCr430 · AISI/SAE 5130
Softest condition — best for cold forming, deep machining or before final quench and temper.
Values for the A condition
Other SCr430 tempers and conditions
SCr430 is listed in 8 conditions; see the grade overview at SCr430.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AThis page Solution annealed | Softest condition — best for cold forming, deep machining or before final quench and temper. | 340 | 560 | 28 | 170 HB | — |
Hot rolled | Cheapest mill condition for parts that will be heat treated after rough machining. | 380 | 620 | 24 | 187 HB | 7.8 % IACS |
Normalized | Uniform fine-grain structure for forgings and weldments where full Q&T strength is not needed. | 450 | 700 | 22 | 210 HB | 7.8 % IACS |
Cold drawn | Close-tolerance bright bar with raised strength for shafts machined without further heat treatment. | 620 | 730 | 12 | 17 HRC | 7.7 % IACS |
QTDefault Quenched and tempered | Standard supply/service condition: 850–880 °C oil quench, 520–620 °C temper for balanced strength and toughness. | 720 | 880 | 18 | 27 HRC | — |
Induction hardened | Choose for shaft journals, splines and cam surfaces needing wear resistance over a tough Q&T core. | 730 | 900 | 15 | 52 HRC | 7.5 % IACS |
Q&T to 28–32 HRC | Specify when a defined hardness band is needed for shafts, keyed drives and machined fasteners. | 830 | 960 | 16 | 30 HRC | 7.8 % IACS |
Q&T to 32–36 HRC | Maximum practical through-hardened strength for SCr430 in small sections; toughness begins to drop. | 950 | 1,080 | 14 | 34 HRC | 7.8 % IACS |
What is SCr430-A?
SCr430-A is SCr430 in the A temper — softest condition — best for cold forming, deep machining or before final quench and temper. SCr430-A 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 205 GPa (29.7 Msi). SCr430-A 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; A is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
Limitations
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
SCr430-A properties
Typical room-temperature values for SCr430-A; 11 are specific to this condition. Other listed values are SCr430 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SCr430-A 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
SCr430-A 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 205 GPa (29.7 Msi).
Thermal6
SCr430-A is rated for continuous service to 350°C (662 °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
SCr430-A 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 SCr430-A takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
SCr430-A's machinability is good (60/100, better than 83% of steel grades); weldability fair (45/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SCr430-A
Is SCr430 easy to machine?
Machines like 4130-class steel — best turned/milled in annealed or ≤300 HB Q&T state with carbide tooling and rigid setups; rough machine then heat treat, finish after temper.
Can SCr430 be welded?
Weldable with low-hydrogen filler but carbon equivalent ~0.6 demands 200–300 °C preheat, controlled interpass and post-weld temper/stress relief to avoid HAZ cracking.
Can SCr430 be formed, bent or molded?
Cold form only in the annealed condition with generous bend radii; hot forge 1150–850 °C followed by normalizing or full anneal.
What surface finishes work on SCr430?
No inherent corrosion resistance — protect with zinc/Zn-Ni plating, phosphate + oil, black oxide, hard chrome or paint; bake plated Q&T parts to relieve hydrogen.
SCr430 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 |
|---|---|---|
| CJIS G 4053 | 0.28 – 0.33 | 0.3 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Cr | 0.9 – 1.2 | 1.05 |
| Niresidual max | ≤ 0.25 | — |
| Curesidual max | ≤ 0.3 | — |
| Fe | balance | — |
SCr430-A — frequently asked
What is SCr430-A used for?
SCr430-A is typically used for shafts, bolts and machine structural parts. In short: mid-strength chrome shaft steel; 4130-class machinability; induction-hardenable surfaces.
What is the yield strength of SCr430-A?
SCr430-A 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 8 listed tempers.
Is SCr430-A easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like 4130-class steel — best turned/milled in annealed or ≤300 HB Q&T state with carbide tooling and rigid setups; rough machine then heat treat, finish after temper.
Can SCr430-A be welded?
With care — weldability is rated fair (45/100). Weldable with low-hydrogen filler but carbon equivalent ~0.6 demands 200–300 °C preheat, controlled interpass and post-weld temper/stress relief to avoid HAZ cracking.
What surface finishes work on SCr430-A?
No inherent corrosion resistance — protect with zinc/Zn-Ni plating, phosphate + oil, black oxide, hard chrome or paint; bake plated Q&T parts to relieve hydrogen.
Can SCr430-A be formed, bent or molded?
Cold form only in the annealed condition with generous bend radii; hot forge 1150–850 °C followed by normalizing or full anneal.
What is the maximum service temperature of SCr430-A?
SCr430-A is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SCr430-QT and SCr430-A?
QT is the default condition — standard supply/service condition: 850–880 °C oil quench, 520–620 °C temper for balanced strength and toughness. A: softest condition — best for cold forming, deep machining or before final quench and temper. Yield strength is 720 MPa in QT versus 340 MPa in A.
Sources
- JIS G 4053 — Low-alloyed steels for machine structural use — JISC (2016)
- GB/T 3077 — Alloy structural steels (30Cr) — SAC (2015)
- SAE J404 / ASTM A29 — Chemical compositions of alloy steels (5130) — 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 (30Cr) (2026)
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.