Steel ZG30CrMnSi Q&T 38-42HRC
Hardness band
Maximum practical strength/wear condition for small or thin-wall castings; toughness and weldability drop sharply, distortion risk is high.
Values for the Q&T 38-42HRC condition
Other ZG30CrMnSi tempers and conditions
ZG30CrMnSi is listed in 8 conditions; see the grade overview at ZG30CrMnSi.
- A
- F
- SR
- N+T
- N
- Q&T 240-280HB
- Q&T 30-35HRC
- Q&T 38-42HRC
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 |
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 | — |
Q&T 38-42HRCThis page 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 Q&T 38-42HRC?
ZG30CrMnSi Q&T 38-42HRC is ZG30CrMnSi heat treated to Q&T 38-42HRC — maximum practical strength/wear condition for small or thin-wall castings; toughness and weldability drop sharply, distortion risk is high. ZG30CrMnSi Q&T 38-42HRC has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 93% of steel grades. Elongation at break is 7% and the elastic modulus is 205 GPa (29.7 Msi). ZG30CrMnSi Q&T 38-42HRC 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; Q&T 38-42HRC is available on request or by drawing note.
Advantages
- High strength — 1,050 MPa (152 ksi), better than 93% of steel grades
Limitations
- Limited ductility — 7%, worse than 96% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Difficult to machine — 22/100, worse than 95% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 86% of steel grades
ZG30CrMnSi Q&T 38-42HRC properties
Typical room-temperature values for ZG30CrMnSi Q&T 38-42HRC; 14 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 Q&T 38-42HRC 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 Q&T 38-42HRC has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 93% of steel grades. Elongation at break is 7% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
ZG30CrMnSi Q&T 38-42HRC is rated for continuous service to 200°C (392 °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 Q&T 38-42HRC 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 Q&T 38-42HRC 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 Q&T 38-42HRC's machinability is poor (22/100, worse than 95% of steel grades); weldability not recommended (12/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZG30CrMnSi Q&T 38-42HRC
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 Q&T 38-42HRC — frequently asked
What is ZG30CrMnSi Q&T 38-42HRC used for?
ZG30CrMnSi Q&T 38-42HRC 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 Q&T 38-42HRC?
ZG30CrMnSi Q&T 38-42HRC has a typical yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 93% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is ZG30CrMnSi Q&T 38-42HRC easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% 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 Q&T 38-42HRC be welded?
Not readily — weldability is rated not recommended (12/100). 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 Q&T 38-42HRC?
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 Q&T 38-42HRC 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 Q&T 38-42HRC?
ZG30CrMnSi Q&T 38-42HRC is rated for continuous use to about 200°C (392 °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.