Steel SCM430
JIS SCM430 · AISI/SAE 4130 · GB 30CrMo
SCM430 is a JIS chromium-molybdenum low-alloy steel, cross-referenced to AISI 4130, GB 30CrMo and EN 25CrMo4, and normally supplied annealed, normalized, hot rolled, cold drawn or quenched and tempered.
Reference datasheet — SCM430 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the QT-JIS condition
SCM430 tempers and conditions
SCM430 is supplied in 9 conditions, soft to hard. QT-JIS is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition for deep machining, cold forming or as a pre-heat-treat blank. | 360 | 560 | 28 | 163 HB | — |
Hot rolled | Cheapest mill condition for forging stock or parts that will be heat treated after machining. | 390 | 620 | 22 | 11 HRC | 7.7 % IACS |
Normalized | Uniform fine-grain structure with good toughness; standard condition for 4130/SCM430 welded tubing and weldments. | 435 | 670 | 25 | 197 HB | — |
Cold drawn | Bright, close-tolerance bar with raised strength; good for shafts machined without further heat treatment. | 580 | 700 | 15 | 14 HRC | 7.7 % IACS |
Q&T 22–26 HRC (high-temper, sour/bolting service) | Soft-tempered condition for maximum toughness and NACE-type sulphide stress cracking limits. | 690 | 830 | 22 | 24 HRC | 7.7 % IACS |
QT-JISDefault Q&T | Standard supply condition: oil quench from ~860 °C, temper ~570–650 °C, for shafts, gears and high-strength bolts. | 760 | 900 | 20 | 27 HRC | — |
Q&T + gas/plasma nitrided surface | Use when a wear/fatigue-resistant hard skin is needed on an already tough Q&T core (shafts, spindles). | 760 | 900 | 18 | 28 HRC | 7.7 % IACS |
Q&T 28–32 HRC | Common machined-part hardness band balancing strength, toughness and tool life. | 830 | 960 | 18 | 30 HRC | — |
Q&T 32–36 HRC (low temper, high strength) | Choose when higher strength/wear is needed in thin sections; toughness and machinability drop. | 970 | 1,100 | 16 | 34 HRC | — |
Supply forms, finishes and certifications
Ways SCM430 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
SR-TUBE | Seamless tube, normalized / stress-relieved | Supply form |
What is SCM430?
SCM430 is a JIS chromium-molybdenum low-alloy steel, cross-referenced to AISI 4130, GB 30CrMo and EN 25CrMo4, and normally supplied annealed, normalized, hot rolled, cold drawn or quenched and tempered. Engineers select it for moderately loaded shafts, bolts and machine components; in the default QT condition it gives 760 MPa yield, 900 MPa tensile, 20 % elongation and about 270 HB (27 HRC) with service to 400 °C. Its lower carbon than SCM435/SCM440 improves weldability (score 55) but caps attainable strength, and it has no inherent corrosion resistance, so plating, phosphating or painting is required. Move to SCM435 when higher hardness in section is needed. SCM430 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). SCM430 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 85% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
What is SCM430 used for?
- shafts
- bolts
- structural machine parts
Advantages
- High strength — 760 MPa (110 ksi), better than 85% of steel grades
SCM430 properties
Typical room-temperature values for SCM430-QT-JIS; bars are the position among steel grades.
Physical3
SCM430 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
SCM430 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 85% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SCM430 is rated for continuous service to 400°C (752 °F). It conducts heat at 42.7 W/m·K (24.7 BTU/hr·ft·°F), better than 50% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
SCM430 conducts electricity at 7.7 % IACS, worse than 65% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of SCM430 takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability7
SCM430's machinability is fair (48/100, worse than 57% of steel grades); weldability good (55/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. SCM430 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SCM430
Is SCM430 easy to machine?
Best machined annealed or ≤30 HRC; use rigid setups, carbide inserts at 90–140 m/min and finish-grind after heat treatment for tight tolerance.
Can SCM430 be welded?
Weldable by TIG/MIG/SMAW with low-hydrogen 4130/ER80S-D2 filler; preheat 150–260 °C for thick sections and post-weld temper to avoid martensitic cold cracking.
Can SCM430 be formed, bent or molded?
Cold bend only in the annealed/normalized condition with generous radii; hot forge 1150–850 °C followed by normalizing.
SCM430 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 | 0.28 – 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 |
| Mo | 0.15 – 0.3 | 0.22 |
| Niresidual, max | ≤ 0.25 | |
| Curesidual, max | ≤ 0.3 | |
| Fe | balance |
What surface finishes work on SCM430?
No native corrosion protection — apply zinc/phosphate, black oxide, Cr plating or paint; nitriding or induction hardening for wear surfaces.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel SCM430 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does SCM430 cost?
SCM430 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
SCM430 — frequently asked
What is SCM430 used for?
SCM430 is typically used for shafts, bolts and structural machine parts. In short: weldable Cr-Mo shaft steel; AISI 4130 equivalent; tougher than SCM435.
What is the yield strength of SCM430?
SCM430 has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 85% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is SCM430 easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 57% of steel grades). Best machined annealed or ≤30 HRC; use rigid setups, carbide inserts at 90–140 m/min and finish-grind after heat treatment for tight tolerance.
Can SCM430 be welded?
Yes — weldability is rated good (55/100). Weldable by TIG/MIG/SMAW with low-hydrogen 4130/ER80S-D2 filler; preheat 150–260 °C for thick sections and post-weld temper to avoid martensitic cold cracking.
What surface finishes work on SCM430?
No native corrosion protection — apply zinc/phosphate, black oxide, Cr plating or paint; nitriding or induction hardening for wear surfaces.
Can SCM430 be formed, bent or molded?
Cold bend only in the annealed/normalized condition with generous radii; hot forge 1150–850 °C followed by normalizing.
What is the maximum service temperature of SCM430?
SCM430 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 SCM430 QT-JIS and SCM430-A?
QT-JIS is the default condition — standard supply condition: oil quench from ~860 °C, temper ~570–650 °C, for shafts, gears and high-strength bolts. A: softest condition for deep machining, cold forming or as a pre-heat-treat blank. Yield strength is 760 MPa in QT-JIS versus 360 MPa in A.
How much does SCM430 cost?
SCM430 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- JIS G 4105 — Chromium molybdenum steels (SCM430) — JSA (2015)
- GB/T 3077 — Alloy structural steels (30CrMo) — SAC (2015)
- EN 10083-3 (25CrMo4) / SAE J404 (4130) — CEN / SAE (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- MMPDS-Handbook, 4130 steel property tables — Battelle/FAA (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.