Molybdenum and its applications

 

Martensitic stainless steel

The martensitic grades tend to have relatively low chromium levels and some of the chromium that is present is tied up as carbides. This results in a relatively low corrosion resistance, below that of the standard Type 304/304L austenitic grades. Because of their limited toughness and lower corrosion resistance, the martensitic grades are only specified when high strength is required. Common applications include turbine blades, cutlery, furnace parts, fasteners, and shafts.

Chemical Composition* (weight%) of some common martensitic stainless steels**

Common Name	UNS Number	C	Mn	Si	Cr	Ni	Mo	Other
403	S40300	0.15	1.00	0.50	11.5-13.0	0.60	…
410	S41000	0.08-0.15	1.00	1.00	11.5-13.5	0.75	…
XM-30	S41040	0.18	1.00	1.00	11.0-13.0	…	…	Nb 0.05-0.30
414	S41400	0.15	1.0	1.00	11.5-13.5	0.75	1.25-2.50
415	S41500	0.05	0.50-1.00	0.60	11.5-14.0	3.5-5.5	0.50-1.00
416	S41600	0.15	1.25	1.00	12.0-14.0	…	0.60	S 0.15 min.
420	S42000	0.15 min	1.00	1.00	12.0-14.0	…	…
431	S43100	0.20	1.00	1.00	15.0-17.0	1.25-2.50	…
444A	S44402	0.60-0.75	1.00	1.00	16.0-18.0	…	0.75
444B	S44403	0.75-0.95	1.00	1.00	16.0-18.0	…	0.75
444C	S44404	0.95-1.20	1.00	1.00	16.0-18.0	…	0.75

Notes:

*		Taken from ASTM specifications for plate, sheet and strip when available or from company data sheets. For complete compositional requirements consult these sources.
**		Chemistry maximum, unless range or minimum is indicated, EN chemistry does not correspond exactly to ASTM chemistry