Chromium-Molybdenum Alloy Steel Pipes, Fittings and Flange

What are alloy steels and low alloy steels?

According to ASTM A 941 the definition terminology, alloy steels are steels(other than stainless steel) containing deliberate amounts of one or more of the following elements shown in below chart,

Alloying Element	Mass Percent(%) Minimum
Aluminum	0.30
Boron	0.0008
Chromium	0.30
Cobalt	0.30
Copper	0.40
Lead	0.40
Manganese	1.65
Molybdenum	0.08
Nickel	0.30
Niobium	0.06
Silicon	0.60
Titanium	0.05
Tungsten	0.30
Vanadium	0.10
Zirconium	0.05
Any other element, except P, S, N and Carbon	0.10

On the contrary, low alloy steels are alloy steels that contain less than the minimum percentages of alloying elements that define and alloy steel.

Chromium-Molybdenum alloy steels for pipes, fittings and flanges

The Cr-Mo alloy steels are most widely used alloy steels for piping components which are mainly applied to high pressure & high temperature services such as oil refinery pipeline, power plants, heat exchangers, furnace systems and pressure reactor vessels.

1) Seamless pipes: ASTM A 335, Grade P5, P9, P11, P12, P22, P91, P911

2) Butt weld fittings: ASTM A 234, Grade WP5, WP9, WP11, WP12, WP22, WP91, WP911

3) Flanges & Forgings: ASTM A 182, Grade F5, F9, F11, F12, F22, F91, F911

1-1. Chemical composition of ASTM A 335, Gr. P5, P9, P11, P12, P22, P91, P911

SPEC.	CHEMICAL COMPOSITION(%)
ASTM A335	C	Mn	P	S	Si	Cr	Mo	Others
P5	0.15	0.30~0.60	0.025	0.025	0.5	4.00~6.00	0.45~0.65	-
P9	0.15	0.30~0.60	0.025	0.025	0.25~1.00	8.00~10.00	0.90~1.10	-
P11	0.05~0.15	0.30~0.60	0.025	0.025	0.50~1.00	1.00~1.50	0.44~0.65	-
P12	0.05~0.15	0.30~0.61	0.025	0.025	0.5	0.80~1.25	0.44~0.65	-
P22	0.05~0.15	0.30~0.60	0.025	0.025	0.5	1.90~2.60	0.87~1.13	-
P91	0.08~0.12	0.30~0.60	0.02	0.010	0.20~0.50	8.00~9.50	0.85~1.05	*A
P911	0.09~0.13	0.30~0.60	0.02	0.010	0.10~0.50	8.50~10.50	0.90~1.10	*B
All requirements are maximum unless otherwise specified A refers to V(0.18~0.25), N(0.030~0.070), Ni(0.40 max), Al(0.04 max), Cb(0.060~0.10) *B refers to V(0.18~0.25), N(0.030~0.070), Ni(0.40 max), Al(0.04 max), Cb(0.060~0.10), W(0.90~1.10) B(0.0003~0.006), W(0.90~1.10)

1-2. Mechanical properties of ASTM A 234, Gr. WP5, WP9, WP11, WP12, WP22, WP91, WP911

ASTM A335	Tensile Strength (Min. Mpa)	Yield Strength (Min. Mpa)	Elongation L. (Min%)	Elongation Tr. (Min%)
P5	415	205	20	-
P9	415	205	20	-
P11	415	205	20	-
P12	415	220	20	-
P22	415	205	20	-
P91	585	415	30	20
P911	620	440	30	20

2-1. Chemical composition of ASTM A 234, Gr. WP5, WP9, WP11, WP12, WP22, WP91, WP911

SPEC.	CHEMICAL COMPOSITION(%)
ASTM A234	C	Mn	P	S	Si	Cr	Mo	Others
WP5	0.15	0.30~0.60	0.04	0.03	0.5	4.00~6.00	0.44~0.65	-
WP9	0.15	0.30~0.60	0.03	0.03	1.00	8.00~10.00	0.90~1.10	-
WP11	0.05~0.15	0.30~0.60	0.03	0.03	0.50~1.00	1.00~1.50	0.44~0.65	-
WP12	0.05~0.20	0.30~0.80	0.045	0.045	0.6	0.80~1.25	0.44~0.65	-
WP22	0.05~0.15	0.30~0.60	0.04	0.04	0.5	1.90~2.60	0.87~1.13	-
WP91	0.08~0.12	0.30~0.60	0.02	0.01	0.20~0.50	8.00~9.50	0.85~1.05	*A
WP911	0.09~0.13	0.30~0.60	0.02	0.01	0.10~0.50	8.50~9.50	0.90~1.10	*B
All requirements are maximum unless otherwise specified A refers to V(0.18~0.25), N(0.030~0.070), Ti(0.01 max), Al(0.02 max), Co(0.060~0.10), N(0.03~0.07) *B refers to V(0.18~0.25), N(0.040~0.090), Ni(0.40 max), Al(0.02 max), Ti(0.01 max), W(0.90~1.10) B(0.0003~0.006), Zi(0.01 max)

2-2. Mechanical Properties of ASTM A 234, Gr. WP5, WP9, WP11, WP12, WP22, WP91, WP911

ASTM A234	Tensile Strength (Min. Mpa)	Yield Strength (Min. Mpa)	Elongation L. (Min%)	Elongation Tr. (Min%)
WP5	415~585	205	20	-
WP9	415~585	205	20	-
WP11	415~585	205	20	-
WP12	415~585	220	20	-
WP22	415~585	205	20	-
WP91	585~760	415	30	20
WP911	620~840	440	30	20

3-1. Chemical composition of ASTM A 182, Gr. F5, F9, F11, F12, F22, F91, F911

SPEC.	CHEMICAL COMPOSITION(%)
ASTM A182	C	Mn	P	S	Si	Ni	Cr	Mo	Others
F5	0.15	0.30~0.60	0.030	0.030	0.50	0.50	4.00~6.00	0.44~0.65	-
F9	0.15	0.30~0.60	0.030	0.030	0.50~1.00		8.00~10.00	0.90~1.10	-
F11	0.05~0.15	0.30~0.60	0.030	0.030	0.50~1.00		1.00~1.50	0.44~0.65	-
F12	0.05~0.15	0.30~0.60	0.045	0.045	0.50		0.80~1.25	0.44~0.65	-
F22	0.05~0.15	0.30~0.60	0.040	0.040	0.50		2.00~2.50	0.87~1.13	-
F91	0.08~0.12	0.30~0.60	0.020	0.010	0.20~0.50	0.40	8.00~9.50	0.85~1.05	*A
F911	0.09~0.13	0.30~0.60	0.020	0.010	0.10~0.50	0.40	8.50~9.50	0.90~1.10	*B
All requirements are maximum unless otherwise specified A refers to V(0.18~0.25), N(0.030~0.070), Al(0.04 max) *B refers to V(0.18~0.25), N(0.040~0.090), Al(0.04 max), W(0.90~1.10),B(0.0003~0.006)

3-2. Mechanical Properties of ASTM A 182, Gr. F5, F9, F11, F12, F22, F91, F911

ASTM A234	Tensile Strength (Min. Mpa)	Yield Strength (Min. Mpa)	Elongation (Min%)	HB (Min.)
F5	485	275	20	143-217
F9	585	380	20	179-217
F11	415	205	20	121-174
F12	415	220	20	121-174
F22	415	205	20	170
F91	585	415	20	248
F911	620~840	440	19	187-248

Views: Author：hbmetals Date:15/02/07