ASTM A333 Grade 6 Pipe Standard Specification for Seamless and Welded Steel Pipe for Low-Temperature Service

ASTM A333 specification covers wall seamless and welded carbon and alloy steel pipe intended for use at low temperatures. The pipe shall be made by the seamless or welding process with the addition of no filler metal in the welding operation. All seamless and welded pipes shall be treated to control their microstructure. Tensile tests, impact tests, hydrostatic tests, and nondestructive electric tests shall be made in accordance to specified requirements.

ASTM A333 Grade 6 pipe is the most popluar and common grade material for low temperature services 

ASTM A333 Grade 6 Materials and Manufacture

1 Manufacture—Except as provided in paragraph 4.2, the pipe shall be made by the seamless or welding process with the addition of no filler metal in the welding operation. Grade 4 shall be made by the seamless process.

ASTM A333 Grade 6 Heat Treatment:

1 All seamless and welded pipe, other than Grades 8 and 11, shall be treated to control their microstructure in accor-dance with one of the following methods:

2.1.1 Normalize by heating to a uniform temperature of not less than 1500 F [815 deg C] and cool in air or in the cooling chamber of an atmosphere controlled furnace.

2.1.2 Normalize as in 4.2.1.1, and, at the discretion of the manufacturer, reheat to a suitable tempering temperature.

2.1.3 For the seamless process only, reheat and control hot working and the temperature of the hot-finishing operation to a finishing temperature range from 1550 to 1750°F [845 to 945°C] and cool in air or in a controlled atmosphere furnace from an initial temperature of not less than 1550°F [845°C].

2.1.4 Treat as in 4.2.1.3 and, at the discretion of the manufacturer, reheat to a suitable tempering temperature.

2.1.5 Seamless pipe of Grades 1, 6, and 10 may be heat treated by heating to a uniform temperature of not less than 1500掳F [815掳C], followed by quenching in liquid and reheating to a suitable tempering temperature, in place of any of the other heat treatments provided for in 4.2.1.

ASTM A333 Grade 6 Compsition

The steel shall conform to the requirements as to chemical composition prescribed in Table 1.

When Grades 1, 6, or 10 are ordered under this specification, supplying an alloy grade that specially re-quires the addition of any element other than those listed for the ordered grade in Table 1 is not permitted. However, the addition of elements required for the deoxidation of the steel is permitted.

ASTM A333 Grade 6 Tensile Requirements

The material shall conform to the requirements as to tensile properties prescribed in Table 3.

ASTM A333 Grade 6 Pipe Impact Requirements

For Grades 1, 3, 4, 6, 7, 9, and 10, 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, when tested at temperatures in conformance with 14.1 shall be not less than the values prescribed in Table 4. The impact test is not required for Grade 11.

1.1 If the impact value of one specimen is below the minimum value, or the impact values of two specimens are less than the minimum average value but not below the minimum value permitted on a single specimen, a retest shall be allowed. The retest shall consist of breaking three additional specimens and each specimen must equal or exceed the required average value. When an erratic result is caused by a defective speci-men, or there is uncertainty in test procedures, a retest will be allowed.

2 For Grade 8 each of the notched bar impact specimens shall display a lateral expansion opposite the notch of not less than 0.015 in. [0.38 mm].

2.1 When the average lateral expansion value for the three impact specimens equals or exceeds 0.015 in. [0.38 mm] and the value for one specimen is below 0.015 in. [0.38 mm] but not below 0.010 in. [0.25 mm], a retest of three additional specimens may be made. The lateral expansion of each of the retest specimens must equal or exceed 0.015 in. [0.38 mm].

2.2 Lateral expansion values shall be determined by the procedure in Test Methods and Definitions A 370.

2.3 The values of absorbed energy in foot-pounds and the fracture appearance in percentage shear shall be recorded for information. A record of these values shall be retained for a period of at least 2 years.

ASTM A333 Grade 6 Pipe Lengths

If definite lengths are not required, pipe may be ordered in single random lengths of 16 to 22 ft (Note 3) with 5 % 12 to 16 ft (Note 3), or in double random lengths with a minimum average of 35 ft (Note 3) and a minimum length of 22 ft (Note3)with 5 % 16 to 22 ft (Note 3).

ASTM A333 Grade 6 Pipe General Requirements

Material furnished to this specification shall conform to the applicable requirements of the current edition of Specification A 999/A 999M unless otherwise provided herein.

ASTM A333 Grade 6 Pipe Hydrostatic or Nondestructive Electric Test

1 Each pipe shall be subjected to the nondestructive electric test or the hydrostatic test. The type of test to be used shall be at the option of the manufacturer, unless otherwise specified in the purchase order.

2 The hydrostatic test shall be in accordance with Specification A 999/A 999M.

3 Nondestructive Electric Test nondestructive electric tests shall be in accordance with Specification A 999/A 999M, with the following addition:

3.1 If the test signals were produced by visual imperfec-tions (listed in 15.3.2), the pipe may be accepted based on visual examination, provided the imperfection is less than 0.004 in. (0.1 mm) or 12.5% of the specified wall thickness (whichever is greater).

ASTM A333 Grade 6 Pipe Product Marking

1 Except as modified in 16.1.1, in addition to the marking prescribed in Specification A 999/A 999M, the mark-ing shall include whether hot finished, cold drawn, seamless or welded, the schedule number and the letters “LT” ollowed by the temperature at which the impact tests were made, except when a lower test temperature is required because of reduced specimen size, in which case, the higher impact test tempera-ture applicable to a full-size specimen should be marked.

1.1 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 S1 is specified

1.2 When the pipe is furnished in the quenched and tempered condition, the marking shall include the letters “QT,” and the heat treatment condition shall be reported to the purchaser or his representative.

Referred ASTM Documents for ASTM A333 Pipes

a. ASTM A370 The test plan for the definitions for the mechanical strength test of the steel products
b. ASTM A999/ A999M The specification for the general requirements of stainless and alloy steel pipe

c. ASTM A671 The specification for ERW EFW steel pipe for lower temperature and atmospheric applications
d. E23 The test plan for notched bar impact testing for the iron and steel materials
e. E165 Practice for liquid penetrant examination for industry
f. E709 Guide for magnetic practice testing