{"id":3573,"date":"2026-09-16T11:01:47","date_gmt":"2026-09-16T08:01:47","guid":{"rendered":"https:\/\/www.defencemetal.com\/index.php\/en\/maraging-300\/"},"modified":"2026-09-25T16:25:20","modified_gmt":"2026-09-25T13:25:20","slug":"maraging-300","status":"publish","type":"page","link":"https:\/\/www.defencemetal.com\/index.php\/en\/maraging-300\/","title":{"rendered":"Maraging 300"},"content":{"rendered":"

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Maraging 300 \/ (1.6358) \/ UNS K93120 \/ AMS 6514 \/ AMS 6521<\/h1>\n
DEFENCE METAL<\/span><\/p>\n
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Maraging 300<\/div>\n
UNS K93120 \u00b7 W.Nr. 1.6358 (also 1.6354) \u00b7 X2NiCoMo18-9-5 \u00b7 18Ni(300) \/ C300 \u00b7 18.0-19.0% Ni \u2013 8.5-9.5% Co \u2013 4.6-5.2% Mo \u2013 0.50-0.80% Ti \u2013 0.05-0.15% Al \u2013 C \u2264 0.03%<\/div>\n
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Not to be confused with<\/div>\n

Maraging 250<\/a>Maraging 350<\/a><\/div>\n<\/div>\n

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For what<\/div>\n
The most widely used grade of the maraging family. An essentially carbon-free iron-nickel martensitic precipitation-hardening steel that hardens by intermetallic precipitation, not carbides.<\/div>\n<\/div>\n
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Forms<\/div>\n
Round bar \u00b7 Flat bar \u00b7 Plate \u00b7 Sheet \u00b7 Tube \u00b7 Forgings<\/div>\n<\/div>\n
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Standards<\/div>\n
AMS 6514<\/b> (bars, forgings, mechanical tubing, rings, forging stock \u2014 consumable electrode vacuum melted, annealed) \u00b7 AMS 6521<\/b> (sheet, strip, plate \u2014 consumable electrode melted, solution heat treated) \u00b7 AMS 6463<\/b> (welding wire, vacuum melted) \u00b7 MIL-S-46850 (300 ksi class; bar, plate, sheet, strip, forgings, extrusions) \u00b7 ASTM A538 Grade C (MAR-18-300, pressure vessel plate \u2014 the standard is no longer active) \u00b7 W.Nr. 1.6358 \/ X2NiCoMo18-9-5
The AMS numbers have been verified against the grade, because they are frequently confused in the trade. The nominal compositions in the SAE title records are: AMS 6512 = 18Ni-7.8Co-4.9Mo-0.40Ti (Maraging 250), AMS 6514 = 18.5Ni-9.0Co-4.9Mo-0.65Ti (Maraging\u2026<\/span><\/div>\n<\/div>\n
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Advantage<\/div>\n
The part is machined to finished size soft, then hardened, and its dimensions barely move. In the solution annealed condition it is 28-35 HRC and is machined in that state; 3-6 hours at 480-510 \u00b0C raises it to 50-55 HRC with no quench.<\/div>\n<\/div>\n
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Welding<\/div>\n
Filler metal: maraging wire of approximately the same composition as the base metal; for Maraging 300 the verified AMS number is AMS 6463<\/b> (18.5Ni-8.5Co-5.2Mo-0.72Ti-0.10Al, vacuum melted).<\/div>\n<\/div>\n
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Limits<\/div>\n
It is not stainless. It contains no chromium and does not exhibit passive behaviour in 3% NaCl; it rusts like carbon steel in the atmosphere and in marine environments and must be protected (cadmium plating, phosphating, paint or similar). Carpenter data sheets classify its corrosion resistance as ‘Humidity Restricted’;<\/div>\n<\/div>\n
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Compiled from manufacturer data sheets \u00b7 confirm against the current specification before ordering<\/div>\n<\/div>\n<\/div>\n

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