ASTM A541 Specification

Scope
Chemical Composition
Mechanical Properties

This specification² covers requirements for quenched and tempered carbon and alloy steel forgings for pressure vessel components. 1.2 All grades are considered weldable under proper conditions. Welding technique is of fundamental importance, and it is presupposed that welding procedure and inspection will be in accordance with approved methods for the grade of material used.

Chemical Composition

	Composition, %
	Grade 1	Grade 1A	Grade 2	Grade 3	Grade 1C	Grade 11 Class 4	Grade 22 Classes 4 and 5	Grade 4N	Grade 5	Grade 3V	Grade 22 Class 3	Grade 22V	Grade 3VCb
Carbon	0.35 max	0.30 max	0.27 max	0.25 max	0.18 max	0.10–0.20	0.05–0.15	0.23 max	0.23 max	0.10–0.15	0.11–0.15	0.11–0.15	0.10-0.15
Manganese	0.40–0.90	0.70–1.35	0.50–0.90	1.20–1.50	1.30 max	0.30–0.80	0.30–0.60	0.20–0.40	0.20–0.40	0.30–0.60	0.30–0.60	0.30–0.60	0.30-0.60
Phosphorus	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.020 max	0.015 max	0.015 max	0.020 max
Sulfur	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.025 max	0.020 max	0.015 max	0.010 max	0.010 max
Silicon^A	0.35 max	0.40 max	0.35 max	0.35 max	0.35 max	0.50–1.00	0.50 max	0.30 max	0.30 max	0.10 max	0.50 max	0.10 max	0.10 max
Nickel	0.40 max	0.40 max	0.50–1.00	0.40–1.00	0.25 max	0.50 max	0.50 max	2.8–3.9	2.8–3.9	. . .	0.25 max	0.25 max	0.25 max
Chromium	0.25 max	0.25 max	0.25–0.45	0.25 max	0.15 max	1.00–1.50	2.00–2.50	1.25–2.00	1.25–2.00	2.8–3.3	2.00–2.50	2.00–2.50	2.7-3.3
Molybdenum	0.10 max	0.10 max	0.55–0.70	0.45–0.60	0.05 max	0.45–0.65	0.90–1.10	0.40–0.60	0.40–0.60	0.90–1.10	0.90–1.10	0.90–1.10	0.90-1.10
Vanadium	0.05 max	0.05 max	0.05 max	0.05 max	0.02–0.12	0.05 max	0.05 max	0.03 max	0.08 max	0.20–0.30	0.02 max	0.25–0.35	0.20-0.30
Titanium	...	...	...	...	...	...	...	...	...	0.015–0.035	...	0.030 max	0.015 max
Boron	...	...	...	...	...	..	...	...	...	0.001–0.003	...	0.0020 max
Copper	...	...	...	...	...	...	...	...	...	...	...	0.20 max	0.25 max
Columbium	...	...	...	...	...	..	...	...	...	...	...	0.07 max	0.015-0.070
Calcium	...	...	...	...	...	..	...	...	...	...	...	0.015 max^B	0.0005-0.0150

Note:

A. When vacuum carbon-deoxidation is required for the classes included in Supplementary Requirements S10, the silicon content shall be 0.10 % max.
B. For Grade 22V, rare earth metals (REM) may be added in place of calcium, subject to agreement between the producer and the purchaser. In that case the total amount of REM shall be determined and reported.

Mechanical Properties

	Grade 1 and 1A	Grades 2 Class 1, 3 Class 1, 1C and 11 Class 4	Grade 2 Class 2 and Grade 3 Class 2	Grade 22 Class 4	Grade 22 Class 5	Grade 4N Class 1 and Grade 5 Class 1	Grades 4N Class 2 and 5 Class 2	Grade 4N Class 3	Grades 3V and 22V	Grade 22 Class 3	Grade 3VCb
Tensile strength, ksi [MPa]	70–95 [485–655]	80–105 [550–725]	90–115 [620–795]	105–130 [725–895]	115–140 [795–965]	105–130 [725–895]	115–140 [795–965]	90–115 [620–795]	85–110 [585–760]	85–110 [585–760]	85–110 [585-760]
Yield strength (0.2 % offset), min, ksi [MPa]	36 [250]	50 [345]	65 [450]	85 [585]	100 [690]	85 [585]	100 [690]	70 [485]	60 [415]	55 [380]	60 [415]
Elongation in 2 in. or 50 mm, min, %	20	18	16	16	15	18	16	20	18	18	18
Reduction of area, min, %	38	38	35	45	40	48	45	48	45	45	45