Steel ZG30CrMnSi-SR (Stress relieved)
Heat-treated state
Applied after casting, rough machining or weld repair to remove residual stress with minimal change to strength.
Values for the SR condition
Other ZG30CrMnSi tempers and conditions
ZG30CrMnSi is listed in 8 conditions; see the grade overview at ZG30CrMnSi.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Pick for maximum machinability and lowest hardness before final quench-and-temper, or to relieve casting stresses fully. | 360 | 620 | 18 | 180 HB | 7.7 % IACS |
As fabricated | Cheapest state for lightly loaded or later-heat-treated castings; coarse, segregated structure with high residual stress and low toughness. | 420 | 700 | 8 | 17 HRC | 7.5 % IACS |
SRThis page Stress relieved | Applied after casting, rough machining or weld repair to remove residual stress with minimal change to strength. | 440 | 690 | 13 | 15 HRC | 7.5 % IACS |
N+TDefault Normalized and tempered | Standard supply condition for general engineering and structural castings: good balance of strength, ductility and impact toughness with low residual stress. | 470 | 700 | 14 | 210 HB | — |
Normalized | Refines the as-cast dendritic structure and homogenizes properties; usually followed by tempering for structural castings. | 520 | 780 | 11 | 21 HRC | 7.4 % IACS |
quenched and tempered (high-temperature temper) | Choose when higher yield strength than N+T is needed while keeping good toughness and machinability for finish-machined castings. | 700 | 880 | 12 | 26 HRC | — |
quenched and tempered (medium temper) | For wear-and-load duty parts (levers, links, gear blanks) where higher strength is required and welding is not planned. | 850 | 1,030 | 10 | 32 HRC | — |
quenched and low-temperature tempered | Maximum practical strength/wear condition for small or thin-wall castings; toughness and weldability drop sharply, distortion risk is high. | 1,050 | 1,250 | 7 | 40 HRC | — |
What is ZG30CrMnSi-SR?
ZG30CrMnSi-SR is ZG30CrMnSi heat treated to SR — applied after casting, rough machining or weld repair to remove residual stress with minimal change to strength. ZG30CrMnSi-SR has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 50% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi). ZG30CrMnSi-SR has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,425°C (2,597 °F). N+T is the default condition FabDigit quotes; SR is available on request or by drawing note.
Limitations
- Limited formability — 18/100, worse than 84% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
ZG30CrMnSi-SR properties
Typical room-temperature values for ZG30CrMnSi-SR; 23 are specific to this condition. Other listed values are ZG30CrMnSi reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
ZG30CrMnSi-SR has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
ZG30CrMnSi-SR has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 50% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
ZG30CrMnSi-SR is rated for continuous service to 400°C (752 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical2
ZG30CrMnSi-SR has an electrical resistivity of 2.3×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of ZG30CrMnSi-SR takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 75%.
Manufacturability8
ZG30CrMnSi-SR's machinability is fair (46/100, worse than 59% of steel grades); weldability fair (37/100); formability poor (18/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZG30CrMnSi-SR
Is ZG30CrMnSi easy to machine?
Machine in the annealed or N+T state (≤240 HB) with coated carbide; expect abrasive cast skin — remove scale first and use rigid setups, reduce speed ~30 % above 300 HB.
Can ZG30CrMnSi be welded?
Weldable only with care: Ceq is high, so preheat 200–300 °C, use low-hydrogen/matching Cr-Mn-Si consumables, control interpass temperature and post-weld temper at 600–650 °C.
Can ZG30CrMnSi be formed, bent or molded?
Sand or investment cast; Si gives good fluidity but the alloy is hot-tear and shrinkage sensitive — use generous fillets, directional solidification, risers and controlled mould cooling.
What surface finishes work on ZG30CrMnSi?
No natural corrosion resistance: shot blast then phosphate + paint, zinc-rich primer, or zinc/nickel plating; can be nitrided or induction hardened locally for wear surfaces.
ZG30CrMnSi 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 |
|---|---|---|
| Cmedium carbon for strength after heat treatment | 0.25 – 0.35 | 0.3 |
| Sisolid-solution strengthening, improves fluidity | 0.6 – 1 | 0.8 |
| Mn | 0.9 – 1.2 | 1.05 |
| Crhardenability | 0.5 – 0.8 | 0.65 |
| Simpurity limit | ≤ 0.04 | — |
| Pimpurity limit | ≤ 0.04 | — |
| Fe | balance | — |
ZG30CrMnSi-SR — frequently asked
What is ZG30CrMnSi-SR used for?
ZG30CrMnSi-SR is typically used for heavy machinery frames, gear blanks and structural castings. In short: high-hardenability cast steel; cast 30CrMnSi equivalent; strength over weldability.
What is the yield strength of ZG30CrMnSi-SR?
ZG30CrMnSi-SR has a typical yield strength of 440 MPa (63.8 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 50% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is ZG30CrMnSi-SR easy to machine?
Reasonably — machinability is rated fair (46/100, worse than 59% of steel grades). Machine in the annealed or N+T state (≤240 HB) with coated carbide; expect abrasive cast skin — remove scale first and use rigid setups, reduce speed ~30 % above 300 HB.
Can ZG30CrMnSi-SR be welded?
With care — weldability is rated fair (37/100). Weldable only with care: Ceq is high, so preheat 200–300 °C, use low-hydrogen/matching Cr-Mn-Si consumables, control interpass temperature and post-weld temper at 600–650 °C.
What surface finishes work on ZG30CrMnSi-SR?
No natural corrosion resistance: shot blast then phosphate + paint, zinc-rich primer, or zinc/nickel plating; can be nitrided or induction hardened locally for wear surfaces.
Can ZG30CrMnSi-SR be formed, bent or molded?
Sand or investment cast; Si gives good fluidity but the alloy is hot-tear and shrinkage sensitive — use generous fillets, directional solidification, risers and controlled mould cooling.
What is the maximum service temperature of ZG30CrMnSi-SR?
ZG30CrMnSi-SR 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 ZG30CrMnSi N+T and ZG30CrMnSi-A?
N+T is the default condition — standard supply condition for general engineering and structural castings: good balance of strength, ductility and impact toughness with low residual stress. A: pick for maximum machinability and lowest hardness before final quench-and-temper, or to relieve casting stresses fully. Yield strength is 470 MPa in N+T versus 360 MPa in A.
Sources
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Steel Castings Handbook — SFSA / ASM International (1995)
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.