Chemical Composition

Element	Grade LF1	Grade LF2	Grade LF3	Grade LF5	Grade LF6	Grade LF9	Grade LF787
Carbon,max	0.30	0.30	0.20	0.30	0.22	0.20	0.07
Manganese	0.60-1.35	0.60-1.35	0.90 max	0.60-1.35	1.15-1.50	0.40-1.06	0.40-0.70
Phosphorus, max	0.035	0.035	0.035	0.035	0.025	0.035	0.025
Sulfur, max	0.040	0.040	0.040	0.040	0.025	0.040	0.025
SiiconA	0.15-0.30	0.15-0.30	0.20-0.35	0.20-0.35	0.15-0.30	...	0.40 max
Nickel	0.40 maxB	0.40 maxB	3.3-3.7	1.0-2.0	0.40 maxB	1.60-2.24	0.70-1.00
Chromium	0.30 maxB,C	0.30 maxB,C	0.30 maxC	0.30 maxC	0.30 maxB,C	0.30 maxC	0.60-0.90
Molybdenum	0.12 maxB,C	0.12 maxB,C	0.12 maxC	0.12 maxC	0.12 maxB,C	0.12 maxC	0.15--0.25
Copper	0.40 maxB	0.40 maxB	0.40 max	0.40 max	0.40 maxB	0.75-1.25	1.00-1.30
Columbium	0.02 maxD	0.02 maxD	0.02 max	0.02 max	0.02 max	0.02 max	0.02 min
Vanadium	0.08 max	0.08 max	0.03 max	0.03 max	0.04-0.11	0.03 max	0.03 max
Nitrogen	...	...	...	...	0.01-0.000	...	...

Note:

A. When vacuum carbon-deoxidation is required by Supplementary Requirement S4, the silicon content shall be 0.12 % maximum.
B. The sum of copper, nickel, chromium, vanadium and molybdenum shall not exceed 1.00 % on heat analysis.
C. The sum of chromium and molybdenum shall not exceed 0.32 % on heat analysis.
D. By agreement, the limit for columbium may be increased up to 0.05 % on heat analysis and 0.06 % on product analysis.

Mechanical Properties

	Grades
	LF1 and LF5 Class 1	LF2 Classes 1 and 2	LF3 Classes 1 and 2 LF5 Class 2	LF6		LF9	LF787
				Class 1	Classes 2 and 3		Class 2	Class 3
Tensile strength, ksi [MPa]	60-85 [415-585]	70-95 [485-655]	70-95 [485-655]	66-91 [455-630]	75-100 [515-690]	63-88 [435-605]	65-85 [450-585]	75-95 [515-655]
Yield strength, min, ksi [MPa]B,C Elongation:	30 [205]	36 [250]	37.5 [260]	52 [360]	60 [415]	46 [315]	55 [380]	65 [450]
Standard round specimen, or small proportional specimen, min % in	25	22	22	22	20	25	20	20
4D gage length Strip specimen for wall thickness 5⁄16 in. [7.94 mm] and over and for all small sizes tested in full section; min % in 2 in. [50 mm]	28	30	30	30	28	28	28	28
Equation for calculating min elongation for strip specimens thinner than 5⁄16 in. [7.94 mm]; min % in 2 in. [50 mm] t = actual thickness in inches	48t + 13	48t + 15	48t + 15	48 t + 15	48t + 13	48t + 13	48t + 13	48t + 13
Reduction of area, min, %	38	30	35	40	40	38	45	45

Note:

A. See 7.3 for hardness tests.
B. Determined by either the 0.2 % offset method or the 0.5 % extension under load method.
C. For round specimens only

Referenced Documents

ASTM A788/A788M	Specification for Steel Forgings, General Requirements.
ASTM A961/A961M	Specification for Common Requirements for Steel Flanges, Forged Fittings, Valves, and Parts for Piping Applications.
ASME B 16.5	Steel Pipe Flanges and Flanged Fittings.
ASME B 16.9	Factory-Made Wrought Steel Butt-Welding Fittings.
ASME B 16.10	Face-to-Face and End-to-End Dimensions of Ferrous Valves.
ASME B 16.11	Forged Steel Fittings, Socket-Welding and Threaded.
ASME B 16.30	Unfired Pressure Vessel Flange Dimensions.
ASME B 16.34	Valves-Flanged, Threaded, and Welding End.
ASME B 16.47	Large Diameter Steel Flanges.
AWS A 5.1	Mild Steel Covered Arc-Welding Electrodes.
AWS A 5.5	Low-Alloy Steel Covered Arc-Welding Electrodes.
API 600	Steel Gate Valves with Flanged or Butt-Welding Ends.
API 602	Compact Design Carbon Steel Gate Valves for Refinery Use.
API 605	Large Diameter Carbon Steel Flanges.