Steel NM400 · heat-treated state · default condition
Steel NM400 Q&T
Properties of the Q&T condition, compared with the other NM400 tempers.
Standard as-delivered condition of NM400 plate; pick it for general sliding-abrasion wear parts up to ~40 mm thickness.
What is NM400 Q&T?
NM400 Q&T is NM400 heat treated to Q&T — standard as-delivered condition of NM400 plate; pick it for general sliding-abrasion wear parts up to ~40 mm thickness. NM400 Q&T 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 12% and the elastic modulus is 210 GPa (30.5 Msi). NM400 Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Advantages
- High strength — 1,050 MPa (152 ksi), better than 93% of steel grades
Limitations
- Difficult to machine — 25/100, worse than 93% of steel grades
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
NM400 Q&T properties
Typical room-temperature values for NM400 Q&T — 10 properties are specific to this condition; the rest are grade-level values shared by every NM400 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
NM400 Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
NM400 Q&T 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 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
NM400 Q&T is rated for continuous service to 250°C (482 °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 µm/m·K (6.67 µin/in·°F).
Electrical3
NM400 Q&T conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of NM400 Q&T takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 55% of steel grades. Typical recycled content is 20%.
Manufacturability7
NM400 Q&T's machinability is poor (25/100, worse than 93% 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.
Other NM400 tempers and conditions
NM400 is also supplied in 5 other conditions. The full side-by-side table is on the NM400 overview.
- Q&TDefaultStandard as-delivered condition of NM400 plate; pick it for general sliding-abrasion wear parts up to ~40 mm thickness.1,050 MPa yield · 42 HRC
Working with NM400 Q&T
Is NM400 easy to machine?
Machine only with rigid setups and carbide/CBN tooling at low speed and positive feed; drilling and tapping are difficult at 400 HBW — prefer plasma/laser/waterjet cutting plus pre-punched holes.
Can NM400 be welded?
Weldable with low-hydrogen electrodes or solid wire; preheat ~100–150 °C (higher for thick or restrained joints), keep interpass below ~250 °C, control heat input, and expect a softened HAZ — no PWHT above the tempering temperature.
Can NM400 be formed, bent or molded?
Cold bending possible with the bend axis transverse to rolling direction and inner radius ≥3–4 t; use generous die radii, deburr flame-cut edges first, and avoid hot forming above 250 °C to preserve hardness.
What surface finishes work on NM400?
Shot-blast and paint or epoxy-coat for corrosion protection; hard-chrome or thermal-spray overlays are used for extra wear life; not anodizable.
NM400 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 |
|---|---|---|
| CGB/T 24186 max; mills typically 0.16–0.22 for weldability | ≤ 0.3 | 0.2 |
| Si | ≤ 0.7 | 0.3 |
| Mn | ≤ 1.7 | 1.3 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.01 | 0 |
| Crhardenability addition | ≤ 1.2 | 0.5 |
| Niraised in low-temperature impact grades | ≤ 1 | 0.2 |
| Mo | ≤ 0.65 | 0.2 |
| Bboron-treated for through hardening | ≤ 0.01 | 0 |
| Tifixes N for effective boron | ≤ 0.05 | 0.02 |
| Nb | ≤ 0.07 | 0.02 |
| V | ≤ 0.1 | 0.02 |
| Altotal Al, deoxidation | ≥ 0.02 | 0.03 |
| Fe | balance | — |
NM400 Q&T — frequently asked
What is NM400 Q&T used for?
NM400 Q&T is typically used for mining bucket and shovel liners, crusher and transfer chutes, dump truck body liners, hopper and bin wear plates, screen and grizzly plates and conveyor skirt and wear strips. In short: workhorse Chinese wear plate.
What is the yield strength of NM400 Q&T?
NM400 Q&T 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 6 listed tempers.
Is NM400 Q&T easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Machine only with rigid setups and carbide/CBN tooling at low speed and positive feed; drilling and tapping are difficult at 400 HBW — prefer plasma/laser/waterjet cutting plus pre-punched holes.
Can NM400 Q&T be welded?
Yes — weldability is rated good (55/100). Weldable with low-hydrogen electrodes or solid wire; preheat ~100–150 °C (higher for thick or restrained joints), keep interpass below ~250 °C, control heat input, and expect a softened HAZ — no PWHT above the tempering temperature.
What surface finishes work on NM400 Q&T?
Shot-blast and paint or epoxy-coat for corrosion protection; hard-chrome or thermal-spray overlays are used for extra wear life; not anodizable.
Can NM400 Q&T be formed, bent or molded?
Cold bending possible with the bend axis transverse to rolling direction and inner radius ≥3–4 t; use generous die radii, deburr flame-cut edges first, and avoid hot forming above 250 °C to preserve hardness.
What is the maximum service temperature of NM400 Q&T?
NM400 Q&T is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in NM400 Q&T?
Yes — NM400 Q&T is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Wear-resistant steel plate NM400 datasheet and welding guide — Baosteel / Ansteel / HBIS (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
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.