440C in superheated steam service?

[ssinclair]

Does anyone have experience using 440C stainless steel for valve seats in superheated steam service? The steam is approx 2600 psig @ 900F. Looking for good hardness and wear resistance. The material I have read indicates good hardness but problems with corossion if it is tempered above 800F.

 

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Stainless Steel 440 C No Related Metal names.

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Chemistry Data
There is no chemistry data available for this grade.

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Principal Design Features This is a high carbon martensitic stainless with moderate corrosion resistance good strength and the ability to obtain and keep excellent hardness (Rc 60) and wear resistance.

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Applications Ball bearings and races, gage blocks, molds and dies, cutlery, valve components, knives and measuring instruments.

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Machinability Best machined in the annealed condition. Tough, stringy chips can be best handled by the use of chip breakers. Carbide or ceramic tooling is recommended.

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Welding This alloy is not commonly welded due to its tendency to air harden. If it must be welded, preheat to 500 F (260 C) and post weld treat at 1350-1400 F (732-760 C) for 6 hours followed by a slow furnace cooling to avoid cracking. Use similar filler metal and high heat inputs during operations.

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Hot Working Pre-heat to 1400 F (760 C), then bring slowly up to 1900-2200 F (1038-1204 C)before proceeding. Do not work this material below 1700 F (927 C). Cool material slowly after working and once at room temperature, anneal fully.

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Cold Working This alloy is considered only slightly cold workable by common practices.

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Annealing 1550-1600 F (843-871 C), followed by very slow furnace cooling.

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Tempering For maximum properties, soak at 300 F (148 C). Maximum obtainable hardness is RC 60.

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Hardening Bring the material slowly up to 1400 F (760 C), then on to a soak temperature of 1850 F (1010 C), air or oil cool.

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Mechanical Data
There is no Mechnical data available for this grade.

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