NM400 vs NM450 vs NM500: How to Choose Wear Plate Grade

NM400 vs NM450 vs NM500 is the usual shortlist when buyers pick a GB/T 24186 wear-plate grade. Start from duty (sliding abrasion vs impact vs forming), then pick the hardness class. This article gives a decision table and links each grade to its canonical page.

Canonical product page: GB/T 24186 NM450 holds chemistry, full hardness tables, sizes and RFQ fields. This article explains the topic in the title; it is not a second datasheet.

Grade choice table

Grade	Primary surface HBW	Bias
GB/T 24186 NM400	370 to 430	Abrasion + fabrication balance
GB/T 24186 NM450	420 to 480	Middle hardness step
GB/T 24186 NM500	470 to 540	Severe sliding abrasion

Full NM300 to NM600 hardness map

Grade	Nominal HBW	Primary surface band (from canon pages)	Product page
NM300	~300	270 to 330 (<=80 mm)	GB/T 24186 NM300
NM360	~360	330 to 400 (<=80 mm)	GB/T 24186 NM360
NM400	~400	370 to 430 (<=80 mm)	GB/T 24186 NM400
NM450	~450	420 to 480 (<=80 mm)	GB/T 24186 NM450
NM500	~500	470 to 540 (<=70 mm)	GB/T 24186 NM500
NM550	~550	520 to 580 (<=70 mm)	GB/T 24186 NM550
NM600	~600	570 to 640 (<=60 mm)	GB/T 24186 NM600

Bands above are copied from the canonical GB/T 24186 product pages on this site. Confirm the ordered edition and thickness on the MTC.

How to choose

Impact + abrasion: often a slightly lower hardness with toughness control (D/E when ordered).
Pure sliding abrasion: higher HBW if fabrication allows.
Middle ground: GB/T 24186 NM450.
Higher hardness does not always win if bends crack or thickness is wrong.

FAQ

How do I choose between NM400 and NM500?

Choose GB/T 24186 NM400 (about 370 to 430 HBW for <=80 mm) when you need abrasion resistance with better forming and welding balance. Choose GB/T 24186 NM500 (about 470 to 540 HBW for <=70 mm) when sliding abrasion is severe and forming is limited. Start from the wear mode and fabrication plan, not from the highest brochure number.

Is NM450 a middle ground between 400 and 500?

Yes. GB/T 24186 NM450 sits between them with a primary surface band about 420 to 480 HBW for <=80 mm. It is the common step when NM400 wears too fast but NM500 is harder to fabricate for your shop. Confirm thickness bands and chemistry on the canonical page before ordering.

Which grade for impact + abrasion?

Impact-heavy duty often favors a slightly lower hardness class with toughness control - and D/E impact options when ordered on GB/T 24186 grades. Pure hardness chasing can backfire if edges crack. Discuss impact test temperature and energy on the PO, and compare GB/T 24186 NM400, GB/T 24186 NM450 and GB/T 24186 NM500 with your fabricator.

Which grade for pure sliding abrasion?

Higher HBW usually wins if fabrication allows: GB/T 24186 NM500, GB/T 24186 NM550 or GB/T 24186 NM600 depending on severity and thickness limits. Still specify the surface band by thickness and protect cut edges. Use the hardness map on this page rather than guessing.

Does higher hardness always win?

No. Cracking, poor bends, wrong thickness or untreated thermal HAZ can erase hardness gains. Match grade to duty, lock HBW on the PO/MTC, and RFQ via the canonical pages GB/T 24186 NM400, GB/T 24186 NM450 and GB/T 24186 NM500.

Ordering pointer

On the inquiry, write grade GB/T 24186 NM450, thickness, width, length, hardness band, delivery condition and certificate (3.1 or 3.2). Send RFQs via Gangsteel - HENAN GANG IRON AND STEEL CO.,LTD.