A333 Pipe Specifications

NPS 1/4″ – 42″
Schedules 10 through 160, STD, XH and XXH


ASTM A333 covers nominal (average) wall seamless and welded carbon and alloy steel pipe intended for use at low temperatures. Several grades of ferritic steel are included. Some product sizes may not be available under this specification because heavier wall thicknesses have an adverse affect on low-temperature impact properties.

Material & Manufacture

The pipe shall be made by the seamless or welding process with the addition of no filler metal in the welding operation.

Heat Treatment Requirements

All seamless and welded pipe shall be treated to control their microstructure by the following methods: Normalizing per A 333/A 333M-05 section; section or section Quenched and Tempered per A 333/A 333M – 05 section Double Normalized and Tempered per A 333/A 333M – 05 section

Chemical Requirements

Composition, % 
ElementGrade 1Grade 3Grade 6
Carbon, max0.300.190.30
Manganese0.40 – 1.060.31 – 0.640.29 – 1.06
Phosphorous, max0.0250.0250.025
Sulfur, max0.0250.0250.025
Silicon0.18 -0.370.10 min
Nickel3.18 – 3.82

For each reduction of 0.01% carbon below 0.30%, an increase of 0.05% manganese above 1.06% would be permitted to a maximum of 1.35% manganese. When Grade 6 is ordered under this specification, supplying an alloy grade that specifically requires the addition of any element other than those listed for the ordered grade is not permitted. However, the addition of elements required for the deoxidation of the steel is permitted.

Tensile Requirements

The material shall conform to the requirements as proscribed:

Grade 1Grade 3Grade 6
Tensile Strength, min55,00038065,00045060,000415
Yield Strength, min30,00020535,00024035,000240
Elongation in 2 in. or 50 mm, (or 4D), min, %:
Basic minimum elongation for walls 5/16 in. [8 mm] and over in thickness, strip tests, and for all small sizes tested in full section353530203016.5
When the standard round 2-in. or 50-mm gage length or proportionally smaller size test specimen with the gage length equal to 4D (4 times the diameter) is used282022142212
For strip tests, a deduction for each 1/32in. [0.8 mm] decrease in wall thickness below 5/16 in. [8 mm] from the basic minimum elongation of the following percentage1.751.251.501.001.501.00
Elongation in 2 in. or 50 mm, min, %:
Wall ThicknessGrade 1Grade 3Grade 6
5/16 (0.312)8352530203016
9/32 (.281)7.2332428192815
1/4 (.250)6.4322327182715
7/32 (.219)5.6302626
3/16 (.188)4.8282424
5/32 (.156)4262222
1/8 (.125)3.2252121
3/32 (.094)2.4232020
1/16 (.063)1.6211818

Impact Requirements

For Grades 1, 3 and 6, the notched-bar impact properties of each set of three impact specimens, including specimens for the welded joint in welded pipe with wall thicknesses of 0.120 in. [3 mm] and larger, shall not be less than the values prescribed:

Size of Specimen, minMinimum Average Notched Bar Impact Value of Each Set of Three SpecimensMinimum Notched Bar Impact Value of One Specimen Only of a Set Impact Temperature
 ft-lbfJft-lbfJ GradeMin Impact
Test Temp
10 by 1013181014FC
10 by 7.510148111-50-45
10 by 6.67912793-150-100
10 by 579576-50-45
10 by 3.335734
10 by 2.54534

Mechanical Testing

Transverse or Longitudinal Tension Test and Flattening Test, Hardness Test, or Bend Test For material heat treated in a batch-type furnace, tests shall be made on 5% of the pipe from each treated lot. For small lots, at least one pipe shall be tested. For material heat treated by the continuous process, tests shall be made on a sufficient number of pipe to constitute 5% of the lot, but in no case less than 2 pipe. Hydrostatic Test Impact Test One notched bar impact test, consisting of breaking three specimens shall be made from each heat represtented in a heat-treatment load on specimens taken from the finished pipe.


Lengths required shall be specified on order. If no definite lengths required, following practice applies: Single Random — 17′ ~ 24′ lengths Double Random — 36′ ~ 44′ lengths

Required Markings on Each Length

(On Tags attached to each Bundle in case of Bundled Pipe) Markings will adhere to prescribed specifications in A 999/A999M and be: Rolled, Stamped, or Stenciled (Mfrs. Option) In addition, markings will include:

Hot Finished or Cold DrawnManufacture Name
Specification / GradeHydro or NDE
Seamless or Welded
Schedule Number
the letters “LT” followed by the temperature at which the impact tests were made * and **
the letters “QT” when the pipe is furnished in the quenched and tempered condition

* except when a lower test temperature is required because of reduced specimen size, in which case, the higher impact test temperature applicable to a full size specimen would be marked ** when the size of the finished pipe is insufficient to obtain subsize impact specimens, the marking shall not include the letters “LT” followed by an indicated test temperature unless Supplementary Requirement S! is specified.

Referenced Documents

  • ASTM A 370 Test Methods and Definitions for Mechanical testing of Steel Products
  • ASTM A999/A 999M Specification for General requirements for Alloy and Stainless Steel Pipe
  • ASTM A 671 Specification for General requirements for Alloy and Stainless Steel Pipe
  • ASTM E 23 Test Methods for Notched bar Impact testing of Metallic Materials

Order Information

Orders for material under this specification should include the following, as required, to describe the desired material adequately:

QuantityFeet, centimeters, or number of lengths
Name of materialSeamless or Welded Pipe
GradeGrade 1, Grade 3, or Grade 6
SizeNPS or Outside Diameter and Schedule Number of Average Wall Thickness
LengthSpecific or Random
End Finish
Optional Requirements
Heat Analysis Requirement
Stress Relieving
Repair by Welding
Other Temperatures for Impact Test
Hydrostatic Test or Nondestructive Electric Test
Test Report Required
Specification Designation and
Special Requirements or Exceptions to this Specification