ASTM A707 / A707M

This specification covers forged carbon and alloy steel flanges intended primarily for petroleum and gas pipelines in areas subject to low ambient temperatures. Included are flanges to specified dimensions or to dimensional standards such as those MSS, ASME, and API specifications that are referenced in Section 2. Supplementary requirements are provided for use when additional requirements are desired. These shall apply only when specified individually by the purchaser in the order. Eight grades, four yield-strength classes, and three different notch toughness levels are included. The availability of a particular size of flange of a specific grade and class is limited only by the capability of the composition to meet the specified mechanical property requirements. However, current practice normally limits the following:
(a) Grade L1 to Classes 1 and 2,
(b) Grade L2 to Classes 1, 2, and 3,
(c) Grade L3 to Classes 1, 2, and 3,
(d) Grade L4 to Classes 1, 2, and 3,
(e) Grade L7 to Classes 1 and 2, and
(f) Grades L5, L6, and L8 are generally available in any class.
This specification is expressed in both inch-pound units and in SI units. However, unless the order specifies the applicable “M” specification designation (SI units), the material shall be furnished to inch-pound units.

Grade

Grade	Description
L1	-
L2	-
L3	-
L4	-
L5	-
L6	-
L7	-
L8	-

Chemical Properties

Grade	Carbon, max, %	Manganese,%	Phosphorus, max, %	Sulfur, max, %	Silicon, max, %	Chromium,%	Nickel,%	Molybdenum,%	Vanadium,%	Nitrogen,%	Copper,%	Columbium, %
L1	0.23	0.55 - 1.60	0.035	0.040	0.37	0.34 max	0.43 max	0.13 max	0.06 max	...	0.43 max	0.03 max
L2	0.33	0.55 - 1.45	0.035	0.040	0.37	0.34 max	0.43 max	0.13 max	0.06 max	...	0.43 max	0.03 max
L3	0.25	1.05 - 1.60	0.030	0.035	0.32	0.34 max	0.43 max	0.13 max	0.03 – 0.13	0.005–0.035	0.18 minC	0.03 max
L4	0.20	0.40 - 0.70	0.030	0.035	0.37	0.34 max	1.60 – 2.05	0.19 – 0.33	0.06 max	...	0.43 max	0.03 max
L5	0.09	0.35 – 0.75	0.030	0.035	0.37	0.56–0.94	0.67 – 1.03	0.14 – 0.28	0.06 max	...	0.95–1.35	0.02 min
L6	0.09	1.75 – 2.30	0.030	0.035	0.17	0.34 max	0.43 max	0.22 – 0.38	0.06 max	...	0.43 max	0.05–0.11
L7	0.22	1.00 max	0.030	0.035	0.37	0.34 max	3.18 – 3.82	0.13 max	0.06 max	...	0.43 max	0.03 max
L8	0.22	0.15 – 0.45	0.025	0.025	0.37	1.44 – 2.06	2.68 – 3.97	0.35 – 0.65	0.06 max	...	0.43 max	0.03 max

Note : C When specified.

Mechanical Properties

Class	Yield strengthA min, ksi [MPa]	Tensile strength, min, ksi [MPa]	Elongation in 2 in. or 50 mm, min, %	Reduction of area, min, %	Hardness, HBW	Cv energy absorption,B,C min, avg, ft·lbf [J]	Cv energy absorption,B,D min, ft·lbf [J]
Class 1	42 [290]	60 [415]	22	40	149–207	30 [41]	24 [33]
Class 2	52 [360]	66 [455]	22	40	149–217	40 [54]	32 [43]
Class 3	60 [415]	75 [515]	20	40	156–235	50 [68]	40 [54]
Class 4	75 [515]	90 [620]	20	40	179–265	50 [68]	40 [54]