Chrome Moly Plate

here are many chromium molybdenum steel products available, each of which has very different chemical and mechanical properties, but they are often grouped as a single category. Chrome moly is the most common name for this group but other names that are used include chromalloy, croalloy, and Cr-Mo (pronounced “cro-mo”).

Typical applications will include:

« Boilers

« Pressure Vessels

« Heat Exchangers

« Flanges

« Valves

« Ducting

« Pipe Supports

Chrome Moly pressure vessel plates from Brown McFarlane are manufactured to the following steel standards:

ASME SA387

ASTM A387

EN10028-2

Size Range

Chrome Moly plates are available:

Thicknesses:	6 mm -100 mm
Widths:	2000 mm, 2500 mm
Length:	up to 12000 mm

Chrome Moly Plate ASME SA387 and ASTM A387

Both SA387 and A387 are described as a “Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum”. The specification covers alloy steel plates intended primarily for welded boilers and pressure vessels designed for elevated temperature use.

Plates are available under these specifications in several grades each having different nominal Chromium (Cr) and Molybdenum (Mo) contents as follows:

Grade	Nominal Cr Content (%)	Nominal Mo Content (%)
2	0.50	0.50
12	1.00	0.50
11	1.25	0.50
22, 22L	2.25	1.00
21, 21L	3.00	1.00
5	5.00	0.50
9, 91	9.00	1.00

Each grade except Grades 21L, 22L, and 91 is available in two classes of tensile strength described as Class 1 and Class 2.

The most regularly specified grades and hence those that are most readily available from stock are Grades 12, 11, 22, 5, and 9 and in most case stock plates will be produced to the tensile requirements of Class 2.

Chrome Moly Plate SA387 / A387 Grade 11 Class 2

C	Mn	P	S
0.05 – 0.17	0.40 – 0.65	0.025	0.025
Si	Cr	Mo	V
0.50 – 0.80	1.00 – 1.50	0.45 – 0.65	–

Tensile Requirements – SA/A387 Grade 11 Class 2

Yield MPa	Tensile MPa	Elongation (50mm)	Reduc’n Of Area*
310 min	515 to 690	22% min	–

Chrome Moly Plate SA387 / A387 Grade 12 Class 2

C	Mn	P	S
0.05 – 0.17	0.40 – 0.65	0.025	0.025
Si	Cr	Mo	V
0.15 – 0.40	0.80 – 1.15	0.45 – 0.60	–

Tensile Requirements – SA/A387 Grade 12 Class 2

Yield MPa	Tensile MPa	Elongation (50mm)	Reduc’n Of Area*
275 min	450 to 585	22% min	–