The chemical compositions of martensitic, precipitation hardening stainless steel

The chemical compositions for some commonly used martensitic, precipitation hardening stainless steels are provided in the following tables. When specifying stainless steel chemistry, it is important to reference the appropriate ASTM standard and the UNS  (Unified Numbering System) number associated with the specific  alloy or grade.  UNS numbers are internationally recognized specific chemistry requirements.  If common names such as AISI numbers are referenced, the UNS number should also be used to avoid confusion. 

These compositions exclude phosphorus (P), sulfur (S), and silicon (Si).  Chemical composition requirements may vary with the specific product requirements so please refer to the appropriate specification.

Table 1: Common Martensitic Stainless Steel Chemical Compositions (Weight Percent)

Martensitic Stainless Steels
Common Name	UNS No.	C	Cr	Ni	Mo	N	Mn	Cu	Other
410	S41000	0.08-0.15	11.5-13.5	0.75	–	–	1.00	–	–
420	S42000	0.15 min.	12.0-14.0	0.75	0.50	–	1.00	–	–
440A	S44002	0.60-0.75	16.0-18.0	–	0.75	–	1.00	–	–
440C	S44004	0.95-1.20	16.0-18.0	–	0.75	–	1.00	–	–

Table 2: Common Precipitation Hardening Stainless Steel Chemical Compositions (Weight Percent)

Precipitation Hardening Stainless Steels
Common Name	UNS No.	C	Cr	Ni	Mo	N	Mn	Cu	Other
XM-13	S13800	0.05	12.3-13.2	7.5-8.5	2.00-2.50	0.01	0.20	–	Al 0.90-1.35
XM-12	S15500	0.07	14.0-15.5	3.5-5.5	–	–	1.00	2.5-4.5	Cb+Ta 0.15-0.45
632	S15700	0.09	14.0-16.0	6.5-7.7	2.00-3.00	–	1.00	–	Al 0.75-1.50
630	S17400	0.07	15.0-17.5	3.0-5.0	–	–	1.00	3.0-5.0	Cb+Ta 0.15-0.45
631	S17700	0.09	16.0-18.0	6.5-7.7	–	–	1.00	–	Al 0.75-1.50

Notes for All Tables: Date was extracted from ASTM specifications for plate, sheet, and strip when available or from company data sheets.  Chemistries are the maximum percentage, unless range or minimum is indicated.

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