NM360 Wear-Resistant Steel Plate

Product Overview

NM360 is the entry grade of the Chinese quenched and tempered abrasion-resistant plate series and is produced to GB/T 24186-2022. Where NM400 and above are chosen for hardness, NM360 is chosen for the balance it strikes: 330 – 390 HBW is roughly three times the hardness of ordinary structural plate, while the relatively low carbon and alloy content of the grade keeps it the easiest grade in the series to weld, form and machine.

The grade is typically specified where the abrasion is real but not extreme, or where a part has to be built by welding and forming before it is put into service — coal handling chutes and troughs, hopper liners, truck body liners and general plant wear plate. If you need a plate that a workshop can work with using ordinary good practice, rather than one that demands preheat discipline on every cut and every pass, NM360 is the one to price first.

How we supply it differently: plate is sourced from first-tier Chinese mills, and can leave China cut and nested to your drawing, edge-milled, rolled or drilled, and shot blasted to Sa 2.5 with a weldable shop primer. You receive parts, not just plate — and you do not have to schedule blasting, cutting and forming capacity of your own to get there.

Mechanical Properties & Hardness

Figures are the mill’s guaranteed values for NM360E/F. Tensile strength, elongation and impact energy are performance requirements: where they are not specified in the contract, only Brinell hardness is guaranteed, so state them on the order if your incoming inspection is going to test for them.

Chemical Composition (Ladle Analysis, % Max)

The low phosphorus and sulphur ceilings are the point of the grade: the mill’s clean-steel practice holds P at or below 40 ppm, S at or below 10 ppm and H at or below 1.2 ppm in production, which is what keeps the cold-cracking sensitivity and the brittle-to-ductile transition temperature down.

Carbon Equivalent & Weldability

CEQ = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15. These are the mill ceilings for grades ordered to a high-weldability requirement; the actual figure for your heat is on the mill certificate.

Supply Range

Tighter widths and shorter lengths are available as cut-to-size or as nested parts to drawing. Longer plate than 24,000 mm is not rolled in this series.

Typical Applications

• Coal handling and mining machinery — Middle troughs, middle plates and bottom sealing plates of ore containers — a 16 – 60 mm application the grade is regularly supplied against, with core hardness held at ≥ HB360.
• Chutes, hoppers and transfer points — Liner plate for moderate sliding abrasion where the liner has to be cut, rolled and welded on site.
• Truck bodies and buckets — Body liners and wear strips on equipment that is repaired and rebuilt rather than replaced.
• Mixed fabrication work — Anywhere one workshop has to cut, form and weld the same material, and NM400 would make the forming and welding steps materially harder.

Choose NM360 when the wear is moderate or when fabrication effort matters as much as wear life.

Step up to NM400 if the liner is being worn out faster than the maintenance cycle can absorb, or if the abrasion is a sliding rather than an impact duty.

Fabrication: Cutting & Forming

Cutting methods compared

Laser gives the tightest tolerance but the narrowest thickness window; oxy-fuel takes the widest range of thickness at the loosest tolerance; plasma sits between them. Water jet is the only method that introduces no heat at all.

Maximum flame cutting speed

Maximum recommended flame cutting speed in mm/min. The mill datasheet lists a ceiling only from the thickness at which preheat control becomes necessary; thinner plate is cut at higher speed.

Preheat before cutting

Cutting NM360 does not call for a preheat at the thicknesses covered by the mill datasheet — the grade is the softest in the series and is the one grade that can be tapped, not just thread milled. Use the welding preheat table below as the reference for any heat input operation.

• Cut clean. Mill scale, rust and oil all degrade cut quality. Clean the cut line on both faces before cutting, and clear the cutting area top and bottom.
• Tune the process, do not just run it. Nozzle size, gas pressure, cutting method and speed have to be set to the grade and thickness in front of you. Hot cutting — flame, plasma or laser — is the correct method for these grades when it is set up properly.
• Watch narrow cut-offs. Where the part being cut off is narrower than about 200 mm, the cutting heat can soften it through its width. Where that matters, use underwater plasma arc cutting, underwater laser cutting or water jet cutting — the water jet is a cold cut with no heat-affected zone and no local softening at all.
• Shearing. Plate below about 10 mm can be sheared. As the grade gets harder, shear stress and tool wear rise, so blade clearance has to be increased and the blade kept hard, sharp and slightly radiused at the corners.
• Slow cooling helps. Where cutting cracks are a concern, keeping the still-warm cut parts together and covering them so they cool slowly reduces the risk.

Fabrication: Drilling, Milling & Boring

Recommended drilling parameters for NM360, from the mill datasheet. Cool with an 8 – 10 % emulsion and keep chip evacuation smooth — chip evacuation is what governs hole quality, tool life and reliability. If the geometry allows it, use the shortest drill that will reach.

• Milling. Face milling at %s with a hard-coated carbide blade and 0.10 – 0.12 mm per tooth. Use climb milling: it makes thinner chips, puts a small tensile stress on the tool, and the downward cutting force presses the plate onto the table, so the cut is stable and tool wear is low.
• Threads. %s
• Boring. Rough bore first, then finish bore, with a hard-coated carbide blade at about 120 m/min and 0.08 mm per revolution.
• Tool life. Machining data published for wear-resistant plate assumes rigid clamping and a continuous coolant supply. If you get vibration, reduce overhang and cutting speed before you change the tool.

Welding

Minimum preheating temperature, gas-shielded welding, in °C. Preheat depends strongly on thickness, so the table is a floor, not a target.

• Groove preparation. Prepare grooves mechanically wherever possible. Where flame cutting is used, leave machining allowance and then remove the heat-affected zone and oxides by milling, planing or grinding. Narrow grooves — I type, narrow V or U — reduce filler metal and heat input; a groove angle of 30° to 50° is suggested.
• Cleanliness. Clean the groove edges and at least 50 mm either side, and grind out moisture, oil, grease and other contamination. Use a stainless steel brush or a grinding wheel.
• Dry the consumables. Stick electrodes must be dried at 300 – 350 °C for two hours before use; welding flux at 200 – 300 °C for one hour.
• Preheat properly. Whole-plate heating gives better results than local heating. Where local heating is used, the groove and the material 100 mm either side of it must all reach the specified temperature. Electric heating mats or flame heating are both acceptable.
• Why it matters. These grades have a relatively high carbon equivalent, are sensitive to hydrogen, and are prone to cold cracking and to heat-affected-zone softening. Correct preheat, correct consumables and a controlled heat input are what prevent both.

Grade Comparison: NM360 – NM600

The harder the grade, the better the resistance to sliding abrasion — and the harder it is to cut, form, drill and weld. The hardest plate is not automatically the cheapest answer: price the whole cycle, including the fabrication step, before you specify.

International Equivalent Grades

Cross-references are indicative only. They are based on nominal hardness and delivery condition, they are not a statement of equivalence, and grades are not interchangeable between makers — always confirm the actual data sheet for the plate you are offered, including the CEQ and the impact temperature.

Processing & Delivery Services

Tell us the application and the drawing rather than just the grade, and we will quote the plate together with the cutting, forming, machining and surface preparation that gets it to your site ready to fit.

Ordering & Documentation

To quote accurately we need: grade, thickness × width × length (or a nesting drawing), quantity, hardness acceptance range if you are sampling, edge condition (sheared, flame cut or machined), surface condition (bare, blasted, or blasted and primed), destination port and required delivery date.

Every shipment is supplied with a mill test certificate traceable to heat number and plate identification. Where the contract does not specify tensile strength, elongation or impact energy, the mill guarantees Brinell hardness only — so if those properties matter for your acceptance, state them on the order.

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