Introduction
QT400-18L 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 | QT400-18L |
| 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-400-18-LT |
| ISO 1083 | ISO1083/JS/400-18-LT |
Similar Materials
N/A
Reference Standards
| Standard | Standard Title | Edition | Specification | Identifier |
|---|---|---|---|---|
| GB/T 1348 | Spheroidal graphite iron castings | 2019 | QT400-18L | — |
Related Casting Products
Physical Properties
N/A
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) | ≥ 230 MPa | ≥ 220 MPa | ≥ 240 MPa |
| Tensile Strength | ≥ 380 MPa | ≥ 360 MPa | ≥ 400 MPa |
| Elongation | ≥ 15 % | ≥ 12 % | ≥ 18 % |
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) | ≥ 230 MPa | ≥ 220 MPa | ≥ 240 MPa |
| Tensile Strength | ≥ 370 MPa | ≥ 340 MPa | ≥ 390 MPa |
| Elongation | ≥ 12 % | ≥ 10 % | ≥ 15 % |
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 QT400-18L/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
Additional Mechanical Properties
Low-Temperature Properties
Conditions are not identical. Compare each stated condition and applicability separately.
GB/T 1348 — 2019 · Table 2 — Normative
| Property | Test window 1 | Test window 2 | Test window 3 | Test window 4 | Test window 5 | Test window 6 |
|---|---|---|---|---|---|---|
| Impact Energy | ≥ 12 J | ≥ 9 J | ≥ 10 J | ≥ 7 J | ≥ 12 J | ≥ 9 J |
- V-notched specimen machined from separately cast, cast-on or side-by-side cast sample; Test temperature -20 °C; Test at -20 °C; -20; 2; GB/T 229; 2 mm striker radius; Figure 6; Impact testing only when required by the purchaser (7.2.1.2); no requirement at the dashed temperatures
- Test window 1: 30 < t ≤ 60 mm; Mean of three specimens; wall thickness ≤ 60 mm
- Test window 2: 30 < t ≤ 60 mm; Minimum individual specimen; wall thickness ≤ 60 mm
- Test window 3: 60 < t ≤ 200 mm; Mean of three specimens; wall thickness ≤ 200 mm
- Test window 4: 60 < t ≤ 200 mm; Minimum individual specimen; wall thickness ≤ 200 mm
- Test window 5: t ≤ 30 mm; Mean of three specimens; wall thickness ≤ 30 mm
- Test window 6: t ≤ 30 mm; Minimum individual specimen; wall thickness ≤ 30 mm
Welding Conditions
N/A
Applications
Ductile iron GB/T 1348 Grade QT400-18L 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. For this suffix grade, retain the specified impact-test temperature and specimen conditions when selecting a component; the test temperature is not a guaranteed operating-temperature limit.
Need QT400-18L Castings?
Contact us for casting and machining inquiries.
Email Us for a QuoteLast Updated: November 6, 2026