NM400 Wear-Resistant Steel Plate Price

For most heavy-duty wear applications in 2025 we recommend NM400 when you need a cost-effective abrasion plate with Brinell hardness around the 400 HBW band and good weldability; for projects where branded, tightly-toleranced performance or guaranteed impact toughness is mandatory, premium alternatives such as SSAB Hardox® 400 remain the safer (but costlier) choice.

What is NM400

NM400 is a quenched & tempered, abrasion-resistant carbon-alloy plate (the “NM” marking originates from the Chinese phrase for abrasion-resistant) whose nominal Brinell hardness centers around 400 HBW. It is produced to give a balance of hardness and toughness so that components exposed to abrasive sliding and impact wear last much longer than ordinary structural steel. Most commercial NM400 delivered from Chinese mills conforms to the national wear-plate standard (GB/T 24186 series) and is widely used where cost efficiency is a priority.

How NM400 is manufactured

NM400 is normally produced by hot rolling followed by quench and temper cycles (or controlled thermomechanical processing plus tempering). The heat treatment is tailored to produce a hardened surface (through-thickness hardening in many grades) combined with sufficient toughness to resist impact cracking in service. Producers control cooling rates, alloy additions (Cr, Ni, Mo, B etc.) and thickness limits to ensure repeatable hardness and mechanical performance. Manufacturer data sheets specify test locations (e.g., 1–2.5 mm below milled surface for Brinell measurements) and defined sampling rules.

Typical chemical composition & mechanical properties

The composition can vary slightly by mill, but a representative specification for NM400 is:

• Carbon (C): ≤ 0.30% (typical ceiling)

• Silicon (Si): ≤ ~1.0%

• Manganese (Mn): up to ~1.6–2.2% (improves hardenability)

• Chromium (Cr), Nickel (Ni), Molybdenum (Mo): small alloying additions in most commercial heats (Cr ≤ ~1.0%, Ni ≤ ~0.7%)

• Phosphorus & Sulfur: controlled to low ppm levels for toughness.

Mechanical targets (typical ranges): tensile strength ~1000–1250 MPa, elongation (A%) often ≥ 10–12% (thickness-dependent), Brinell hardness band ≈ 360–430 HBW for NM400 deliveries (the “400” is the nominal hardness band). These values are consistent with industry technical sheets and independent supplier PDFs.

Standards & certification

NM400 production is normally ordered to China’s national wear plate standard GB/T 24186 (current: GB/T 24186-2022; earlier editions include GB/T 24186-2009). That standard defines grade designation, mechanical requirements, sampling, impact testing, marking and test reports for NM series plates (NM300, NM360, NM400, NM450, NM500 etc.). When buying for critical applications insist on a mill certificate showing the standard version, heat number, hardness map, tensile and impact test data.

Performance: hardness, toughness and real-world wear

• Abrasion resistance: correlated with Brinell hardness; NM400 performs in the AR400 band which provides a favorable balance between wear life and fabricability.

• Toughness: measured with Charpy V-notch at specified temperatures; manufacturers will specify guaranteed impact energy levels for thicker plates or low-temperature service.

• Wear modes: NM400 resists two main abrasion types — sliding (fine abrasive) and impactive (large particles). For high-impact service or very coarse, sharp aggregates, higher hardness grades (NM450/NM500 or branded Hardox 450/500) can give longer life but at greater cost.

Equivalents & how NM400 compares with branded AR plates

NM400 is widely quoted as the Chinese equivalent to AR400 / Hardox 400 / XAR 400; however, branded plates (e.g., SSAB Hardox® 400) are manufactured under tightly controlled leader-brand processes that guarantee surface quality, guaranteed impact properties, traceability and tighter thickness/hardness tolerances. In practice:

• NM400: cost-effective, widely available, suitable for most applications where a standard AHBR (AR400) band is acceptable.

• Hardox 400 (SSAB): premium, proven performance, broader test and supply traceability — preferred for safety-critical, warranty-backed or OEM applications.

A realistic procurement rule of thumb: choose NM400 where budget and lead time matter and the application is not warranty-sensitive; choose branded Hardox/AR plate for OEMs, customer warranty conditions, or when specifications explicitly require the brand.

Fabrication: cutting, forming and welding notes

• Cutting: plasma and laser cutting are common — expect some surface hardening near kerfs and remove thermal-affected zones if the component is a wear-critical edge.

• Bending/forming: NM400 in thinner gauges (≤ ~8–10 mm) can be bent with correct tooling; thicker plates require pre-heating or roller bending with controlled radii per the mill’s bending guidelines.

• Welding: NM400 is weldable but benefit from preheat and consumables matched to the parent alloy; avoid excessive heat input that reduces near-edge hardness. Use qualified procedures and post-weld heat treatment where the application demands retained toughness. Manufacturer welding guides should be followed.

Typical applications

NM400 is used for: dump truck bodies, crusher liners, excavator buckets, chutes and hoppers, conveyor wear liners, brick-making dies and recycle equipment — essentially anywhere sliding abrasion dominates. When impact energy is very high (like heavy rock with large free-fall drops) higher hardness grades or layered solutions (composite liners) are sometimes preferred.

Quality control & inspection checks at receipt

When NM400 arrives, we recommend a minimum inspection protocol:

• Verify mill certificate (heat no., standard GB/T 24186 version, thickness, hardness map).

• Check Brinell hardness at multiple points (1–2.5 mm below milled surface unless otherwise specified).

• Confirm Charpy V-notch results if low-temperature service is expected.

• Visual check for laminations, surface decarburization and edge quality.

• Maintain sample pieces for destructive testing if the order is for a safety-critical application.

Global price comparison (2025)

Important note: steel pricing is volatile — the figures below are market ranges observed in the supplier and market pages during 2025 and are presented as indicative procurement planning numbers (FOB/EXW or CIF terms and thickness materially affect the price). We cite representative suppliers and market reports for each region.

Price drivers you must consider: thickness (thin plate is cheaper per tonne to ship but more processing), plate finish (milled vs as-rolled), guaranteed impact test results and certificate depth, order quantity (MOQ), delivery Incoterm and steel cycle. Branded plates (SSAB Hardox) can cost 2–3× a budget NM400 plate depending on region and volume.

Decision checklist: when to pick NM400 vs alternatives

• Pick NM400 when: budget and delivery time are primary; the application is moderate abrasion (sliding), and you can accept supplier QC certificates instead of brand guarantees.

• Pick NM450 / NM500 or Hardox 450 / 500 when: particle impact is severe, life-cycle cost justifies higher material cost, or OEM/warranty calls for a branded grade.

• Pick layered composite liners or HARDOX Extreme when: extreme abrasion with high impact and sharp particles requires the highest hardness and specialized processing.

Storage, logistics and shelf life

Store plates flat on bearers, keep dry and covered to avoid corrosion, handle with lifting gear rated for plate weight and avoid edge nicks that concentrate wear. For long logistics chains, ask the supplier for anti-corrosion coatings or oiling and verify packaging for sea/rail shipments. Small orders via platforms will often be packaged for export — verify expected delivery windows and insurance terms.

Sustainability & recycling

NM series plates are typical quenched-and-tempered steels and are recyclable in conventional steel melting operations. Where sustainability matters, request mill statements about scrap origin, CO₂ intensity or any low-carbon initiatives (some leading suppliers publish environmental product declarations). Branded mills (SSAB) also publish sustainability reports for customers demanding low-emissions supply chains.

FAQs

Q1. Is NM400 the same as Hardox 400?
No — NM400 is the Chinese NM-series plate roughly in the AR400 hardness band. It is often equivalent in Brinell hardness to Hardox 400, but branded Hardox is produced to SSAB’s strict process and test regime and therefore carries a premium and stronger traceability. For many applications NM400 is a cost-effective substitute; for warranty-sensitive or OEM-specified work, use the branded product.

Q2. What thicknesses are commonly available?
Common NM400 thicknesses range from ~3–6 mm for light liners up to 20–50+ mm for heavy liners; practical supply range is typically 3–80 mm depending on mill capability. Thickness affects weldability and required heat treatment settings.

Q3. How should I weld NM400?
Use low-hydrogen consumables, match filler tensile properties appropriately, use controlled preheat/post-heat if specified, and follow a qualified welding procedure. Avoid excessive heat input close to edges where you want to preserve hardness. Consult the mill’s welding instructions.

Q4. What tests should I demand on the MTC (mill test certificate)?
At minimum: chemical analysis, tensile test, Brinell hardness map (multiple points), impact (Charpy V) at specified temperature for thick plates, and confirmation of the standard (GB/T 24186 or equivalent).

Q5. Is NM400 suitable for cold climates?
It can be, provided the mill’s impact test temperature and guaranteed toughness meet the service temperature. For low-temperature service, insist on Charpy V notch data at the operating temperature or a lower qualification temperature.