American Piping Products stocks A691 EFW pipe in the grades and classes listed on the following tables:
Pipe gradeSteel typeASTM SpecificationHB, maxA
CM-65carbon-molybdenum steelA204/A204MA201
CM-70carbon-molybdenum steelA204/A204MB201
CM-75carbon-molybdenum steelA204/A204MC201
CMSH-70carbon-manganese-silicon steel, normalizedA537/A537M1
CMS-75carbon-manganese-silicon steelA299/A299M
CMSH-80carbon-manganese-silicon steel, quenched and temperedA537/A537M2
0.5  CR0.5%  chromium, 0.5% molybdenum steelA387/A387M2201
1 CR1% chromium, 0.5% molybdenum steelA387/A387M12201
1.25 CR1.25% chromium, 0.5% molybdenum steelA387/A387M11201
2.25 CR2.25% chromium, 1% molybdenum steelA387/A387M22201
3 CR3% chromium, 1% molybdenum steelA387/A387M21201
5 CR5% chromium, 0.5% molybdenum steelA387/A387M5225
9 CR9% chromium 1% molybdenum steelA387/A387M9241
919% chromium, 1% molybdenum, vanadium, columbiumA387/A387M91241
AHardness values listed are applicable to S3.
ClassHeat treatment of pipeRadiographyPressure test
20stress relievednono
21stress relievedyesno
22stress relievedyesyes
23stress relievednoyes
40normalized and temperednono
41normalized and temperedyesno
42normalized and temperedyesyes
43normalized and temperednoneyes
50quenched and temperednonenone
51quenched and temperedyesnone
52quenched and temperedyesyes
53quenched and temperednoneyes


This specification covers steel pipe 16 inches in outside diameter or larger that is electric fusion welded (EFW) with filler metal added, fabricated from pressure vessel quality plate and suitable for high-pressure service at moderate temperatures. Several grades designate the type of plate used; classes designate the type of heat treatment performed during the manufacture of the pipe, whether the weld is radiographically examined, and if the pipe has been pressure tested.

Chemical composition

Product analysis of plate: The pipe manufacturer shall make an analysis of each mill heat of plate material. The product analysis shall meet the requirements of the plate specification to which the material was ordered.

Product analysis of weld: The pipe manufacturer shall make an analysis of the finished deposited weld material from each 200 feet or fraction thereof. Analysis shall conform to the welding procedure for deposited weld material.

Heat treatment

Classes 10, 11, 12 and 13 are not heat treated. All other classes must be heat treated according to the parameters shown below:

Pipe gradeASTM SpecificationPost-weld heat treat temperature range (stress relieving), °F (°C)Normalizing temperature, max unless otherwise noted, °F (°C)Quenching temperature, max unless otherwise noted, °F (°C)Tempering temperature, min, °F (°C)
CM-65A204/A204M1100-1200 (590-650)1700 (925)
CM-70A204/A204M1100-1200 (590-650)1700 (925)
CM-75A204/A204M1100-1200 (590-650)1700 (925)
CMSH-70A537/A537M1100-1200 (590-650)1700 (925)
CMS-75A299/A299M1100-1200 (590-650)1700 (925)
CMSH-80A537/A537M1100-1200 (590-650)A1700 (925)1100-1250 (590-675)
0.5 CRA387/A387M1100-1300 (590-705)1850 (1010)1700 (925)1150-1375 (620-745)
1 CRA387/A387M1100-1350 (590-730)1850 (1010)1700 (925)1150-1375 (620-745)
1.25 CRA387/A387M1100-1375 (590-745)1850 (1010)1700 (925)1150-1375 (620-745)
2.25 CRA387/A387M1200-1400 (650-760)1850 (1010)1700 (925)1250-1400 (675-760)
3 CRA387/A387M1200-1400 (650-760)1850 (1010)1700 (925)1250-1400 (675-760)
5 CRA387/A387M1200-1400 (650-760)1850 (1010)1700 (925)1250-1400 (675-760)
9 CRA387/A387M1325-1375 (715-745)B1325-1375 (715-745)
91A387/A387M1350-1420 (730-770)1900-2000 (1040-1095)1900 min (1040 min)1350-1440 (730-780)

ARequires quenching and tempering.

B9 CR steel is an air-hardenable steel, at times retaining austenite down to near atmospheric temperature. Good practice is to allow the steel to cool to 150° F or lower before subjecting the steel to a tempering treatment or post-weld heat treatment.

Permissible Variations in Wall Thickness and Weight

Dictated by the requirements of the specification to which the manufacturer ordered the plate.

Permissible Variations in Outside Diameter

Based on circumferential measurement +/-0.5% of the specified outside diameter.

Reference documents

ASTM A20/A20M Specification for General Requirements for Steel Plates for Pressure Vessels
ASTM A370 Test Methods and Definitions for Mechanical Testing of Steel Products
ASTM A387/A387M Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum
ASTM A435/A435M Specification for Straight-Beam Ultrasonic Examination of Steel Plates
ASTM A530/A530M Specification for General Requirements for Specialized Carbon and Alloy Steel Pipe
ASTM E165 Practice for Liquid Penetrant Examination for General Industry
ASTM E709 Guide for Magnetic Particle Testing
ASTM A204/A204M Specification for Pressure Vessel Plates, Alloy Steel, Molybdenum
ASTM A299/A299M Specification for Pressure Vessel Plates, Carbon Steel, Manganese-Silicon
ASTM A537/A537M Specification for Pressure Vessel Plates, Heat-Treated, Carbon-Manganese-Silicon Steel