Introduction
QT350-22 is a spheroidal graphite iron casting grade covered by GB/T 1348. Typical applications include pump housings, valve bodies, bearing supports and equipment brackets.
| Field | Value |
|---|---|
| Designation | QT350-22 |
| Material Type | Cast Iron |
| Sub Type | Ductile Cast Iron |
| Product Form | casting |
Manufacturing Process
Sand Casting
Shell Molding Casting
Lost Foam Casting
Equivalent Materials
| Standard | Material Grade |
|---|---|
| EN 1563 | EN-GJS-350-22 |
| ISO 1083 | ISO1083/JS/350-22 |
Similar Materials
N/A
Reference Standards
| Standard | Standard Title | Edition | Specification | Identifier |
|---|---|---|---|---|
| GB/T 1348 | Spheroidal graphite iron castings | 2019 | QT350-22 | — |
Related Casting Products
Physical Properties
| Property | Value / Unit | Note | Source |
|---|---|---|---|
| Elastic Modulus | 169 GPa | measured at room temperature unless otherwise stated, not an acceptance limit | GB/T 1348 |
| Poisson Ratio | 0.275 | measured at room temperature unless otherwise stated, not an acceptance limit | GB/T 1348 |
| Thermal Conductivity | 36.2 W/(m·K) | Test at 300 °C; measured at room temperature unless otherwise stated, not an acceptance limit | GB/T 1348 |
| Specific Heat | 515 J/(kg·K) | measured at room temperature unless otherwise stated, not an acceptance limit; Temperature range: 20–500 °C | GB/T 1348 |
| Thermal Expansion | 12.5 ×10⁻⁶/K | measured at room temperature unless otherwise stated, not an acceptance limit; Temperature range: 20–400 °C | GB/T 1348 |
| Density | 7.1 kg/dm³ | measured at room temperature unless otherwise stated, not an acceptance limit | GB/T 1348 |
| Maximum Magnetic Permeability | 2136 µH/m | measured at room temperature unless otherwise stated, not an acceptance limit | GB/T 1348 |
| Hysteresis Loss | 600 J/m3 | measured at room temperature unless otherwise stated, not an acceptance limit; B = 1 T | GB/T 1348 |
| Electrical Resistivity | 0.5 µΩ·m | measured at room temperature unless otherwise stated, not an acceptance limit | GB/T 1348 |
Chemical Composition
No specified chemical composition limits in GB/T 1348
Heat Treatment
GB/T 1348–2019
Heat treatment may be required under agreed delivery or retesting conditions. No grade-specific heat-treatment temperature or holding schedule is prescribed.
Mechanical Properties
Core Mechanical Properties
Conditions are not identical. Compare each stated condition and applicability separately.
GB/T 1348 — 2019 · Table 1 — Normative
| Property | 30 < t ≤ 60 mm | 60 < t ≤ 200 mm | t ≤ 30 mm |
|---|---|---|---|
| Yield Strength (Rp0.2) | ≥ 220 MPa | ≥ 210 MPa | ≥ 220 MPa |
| Tensile Strength | ≥ 330 MPa | ≥ 320 MPa | ≥ 350 MPa |
| Elongation | ≥ 18 % | ≥ 15 % | ≥ 22 % |
Common specimen condition: Separately cast, cast-on or side-by-side cast sample
Full original column conditions
- 30 < t ≤ 60 mm — Separately cast, cast-on or side-by-side cast sample · 30 < t ≤ 60 mm
- 60 < t ≤ 200 mm — Separately cast, cast-on or side-by-side cast sample · 60 < t ≤ 200 mm
- t ≤ 30 mm — Separately cast, cast-on or side-by-side cast sample · t ≤ 30 mm
- L0 = 5d; GB/T 228.1; Minimum prescribed value
- Separately cast, cast-on or side-by-side cast sample · 30 < t ≤ 60 mm: wall thickness ≤ 60 mm
- Separately cast, cast-on or side-by-side cast sample · 60 < t ≤ 200 mm: wall thickness ≤ 200 mm
- Separately cast, cast-on or side-by-side cast sample · t ≤ 30 mm: wall thickness ≤ 30 mm
GB/T 1348 — 2019 · Table C.1 — Informative
| Property | 30 < t ≤ 60 mm | 60 < t ≤ 200 mm | t ≤ 30 mm |
|---|---|---|---|
| Yield Strength (Rp0.2) | ≥ 210 MPa | ≥ 200 MPa | ≥ 220 MPa |
| Tensile Strength | ≥ 320 MPa | ≥ 310 MPa | ≥ 340 MPa |
| Elongation | ≥ 15 % | ≥ 12 % | ≥ 20 % |
Full original column conditions
- 30 < t ≤ 60 mm — Specimen cut from the casting · 30 < t ≤ 60 mm
- 60 < t ≤ 200 mm — Specimen cut from the casting · 60 < t ≤ 200 mm
- t ≤ 30 mm — Specimen cut from the casting · t ≤ 30 mm
- source designation QT350-22/C; sampling position and acceptance properties subject to agreement; L0 = 5d; GB/T 228.1; Informative minimum guideline, not an unconditional acceptance requirement; Informative reference value; not an acceptance requirement
- Specimen cut from the casting · 30 < t ≤ 60 mm: wall thickness ≤ 60 mm
- Specimen cut from the casting · 60 < t ≤ 200 mm: wall thickness ≤ 200 mm
- Specimen cut from the casting · t ≤ 30 mm: wall thickness ≤ 30 mm
GB/T 1348 — 2019 · Table G.1 — Informative
| Property | Value |
|---|---|
| Shear Strength | 315 MPa |
- Annex G informative reference data; measured at room temperature unless otherwise stated, not an acceptance limit; Informative reference value; not an acceptance requirement
GB/T 1348 — 2019 · Table G.2 — Informative
| Property | t ≤ 30 mm |
|---|---|
| Tensile Strength | 350 MPa |
Full original column conditions
- t ≤ 30 mm — Specimen cut from casting · diameter ≤25 mm · t ≤ 30 mm
- wall thickness ≤ 30 mm; Informative guideline; stress-controlled fatigue; N = 10^7 cycles, failure probability P = 50% for fatigue data; not an acceptance requirement; Informative reference value
Additional Mechanical Properties
Fatigue Properties
Conditions are not identical. Compare each stated condition and applicability separately.
GB/T 1348 — 2019 · Table G.2 — Informative
| Property | Test window 1 | Test window 2 |
|---|---|---|
| Notched Rotating Bending Fatigue Strength | 115 MPa[1] | — / Not specified |
| Notched Rotating Bending Fatigue Ratio | 0.33[2] | — / Not specified |
| Reversed Tension Compression Fatigue Strength | — / Not specified | 150 MPa[3] |
| Reversed Tension Compression Fatigue Ratio | — / Not specified | 0.43[2] |
| Pulsating Tension Fatigue Strength | — / Not specified | 210 MPa[4] |
| Reversed Torsional Fatigue Strength | — / Not specified | 138 MPa[5] |
| Reversed Torsional Fatigue Ratio | — / Not specified | 0.39[2] |
| Rotating Bending Fatigue Strength | — / Not specified | 168 MPa[6] |
| Rotating Bending Fatigue Ratio | — / Not specified | 0.48[2] |
- diameter ≤25 mm; relevant wall thickness t ≤30 mm; t ≤ 30 mm; wall thickness ≤ 30 mm; Informative guidance, not an acceptance requirement; The source cycle-count wording is inconsistent; N = 10^7 cycles (10 million), P = 50% reference: ISO 1083:2018 Table G.2 footnotes b/c; Supplemental reference; not an official GB corrigendum; Stress-controlled fatigue according to Wöhler; Informative reference value; not an acceptance requirement
- Test window 1: Notched specimen, Kt ≤3 machined from a sample cut from casting
- Test window 2: Unnotched specimen machined from a sample cut from casting
Fracture Toughness
GB/T 1348 — 2019 · Table G.1 — Informative
| Property | Value |
|---|---|
| Fracture Toughness (KIC) | 31 MPa√m |
- Annex G informative reference data; measured at room temperature unless otherwise stated, not an acceptance limit; Informative reference value; not an acceptance requirement
Other Mechanical Properties
GB/T 1348 — 2019 · Table G.1 — Informative
| Property | Value |
|---|---|
| Torsional Strength | 315 MPa |
- Annex G informative reference data; measured at room temperature unless otherwise stated, not an acceptance limit; Informative reference value; not an acceptance requirement
Notes
GB/T 1348 · Edition 2019
[1] Notched Rotating Bending Fatigue Strength: R = -1; approximately 21.8%; Kt ≤ 3; σbwk(R=-1)/Rm ≈ 0.40 - 0.0002 × Rm; Mean source-strength, not a guaranteed limit
[2] Notched Rotating Bending Fatigue Ratio/Reversed Tension Compression Fatigue Ratio/Reversed Torsional Fatigue Ratio/Rotating Bending Fatigue Ratio: Source-not a calculated value
[3] Reversed Tension Compression Fatigue Strength: R = -1; approximately 22.3%; σw/Rm ≈ 0.50 - 0.0002 × Rm; Mean source-strength, not a guaranteed limit
[4] Pulsating Tension Fatigue Strength: R = 0; σmax = 2σ; approximately 9%; σ(R=0)/σ(R=-1) ≈ 0.7; Mean source-strength, not a guaranteed limit
[5] Reversed Torsional Fatigue Strength: R = -1; approximately 14%; τw/Rm ≈ 0.46 - 0.0002 × Rm; Mean source-strength, not a guaranteed limit
[6] Rotating Bending Fatigue Strength: R = -1; approximately 14.2%; σw/Rm ≈ 0.55 - 0.0002 × Rm; Mean source-strength, not a guaranteed limit
Welding Conditions
N/A
Applications
Ductile iron GB/T 1348 Grade QT350-22 is used for pump housings, valve bodies, bearing supports and equipment brackets. These castings are found in fluid-handling equipment, agricultural machinery and general mechanical assemblies. Selection within this family depends on the actual component geometry and loading. Pipes, pipe fittings and associated joints are outside this standard; pressure-retaining machinery parts require the applicable component specification and inspection requirements.
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