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Alloy Steel

Alloy steel is steel that is alloyed with a variety of elements in total amounts between 1.0% and 50% by weight to improve its mechanical properties. Alloy steels are broken down into two groups: low alloy steels and high alloy steels. The difference between the two is disputed. Smith and Hashemi define the difference at 4.0%, while Degarmo, et al., define it at 8.0%.[1][2] Most commonly, the phrase "alloy steel" refers to low-alloy steels. Strictly speaking, every steel is an alloy, but not all steels are called "alloy steels". The simplest steels are iron (Fe) alloyed with carbon (C) (about 0.1% to 1%, depending on type). However, the term "alloy steel" is the standard term referring to steels with other alloying elements added deliberately in addition to the carbon. Common alloyants include manganese (the most common one), nickel, chromium, molybdenum, vanadium, silicon, and boron. Less common alloyants include aluminium, cobalt, copper, cerium, niobium, titanium, tungsten, tin, zinc, lead, and zirconium.

Alloy Steel Products

Pipe Fittings

Seamless, Welded

Pipe Fittings

Seamless, Welded

Elbow, Tee, Cross, Reducer, Bend, Stub End

Forged Fittings

Socket weld, Threaded

Forged Fittings

Socket weld, Threaded

Elbow, Tee, Cross, Coupling, Olets, Union, Bushing

Flanges

Forged, Plate

Flanges

Forged, Plate

SORF, WNRF, BLRF, SWRF

Technical Properties of Alloy Steel

ASTM A234

Specification for Piping Fittings of Wrought Alloy Steel for Moderate and High Temperature Service

Gr. C Mn P
max		 S
max		 Si
WP1 0.28
max		 0.3
0.9		 0.045 0.045 0.1
0.5
WP12 CL1 0.05
0.2		 0.3
0.8		 0.045 0.045 0.6
max
WP12 CL2 0.05
0.2		 0.3
0.8		 0.045 0.045 0.6
max
WP11 CL1 0.05
0.15		 0.3
0.6		 0.03 0.03 0.5
1.0
WP11 CL2 0.05
0.2		 0.3
0.8		 0.04 0.04 0.5
1.0
WP11 CL3 0.05
0.2		 0.3
0.8		 0.04 0.04 0.5
1.0
WP22 CL1 0.05
0.15		 0.3
0.6		 0.04 0.04 0.5
max
WP22 CL3 0.05
0.15		 0.3
0.6		 0.04 0.04 0.5
max
WP5 CL1 0.15
max		 0.3
0.6		 0.04 0.03 0.5
max
WP5 CL3 0.15
max		 0.3
0.6		 0.04 0.03 0.5
max
WP9 CL1 0.15
max		 0.3
0.6		 0.03 0.03 1.0
max
WP9 CL3 0.15
max		 0.3
0.6		 0.03 0.03 1.0
max
WPR 0.2
max		 0.4
1.06		 0.045 0.05  
WP91 0.08
0.12		 0.3
0.6		 0.02 0.01 0.2
0.5
WP911 0.09
0.13		 0.3
0.6		 0.02 0.01 0.1
0.5
Composition, %
Gr. Cr Mo Ni Cu Others
WP1   0.44
0.65		      
WP12 CL1 0.8
1.25		 0.44
0.65		      
WP12 CL2 0.8
1.25		 0.44
0.65		      
WP11 CL1 1.0
1.5		 0.44
0.65		      
WP11 CL2 1.0
1.5		 0.44
0.65		      
WP11 CL3 1.0
1.5		 0.44
0.65		      
WP22 CL1 1.9
2.6		 0.87
1.13		      
WP22 CL3 1.9
2.6		 0.87
1.13		      
WP5 CL1 4.
6.		 0.44
0.65		      
WP5 CL3 4.
6.		 0.44
0.65		      
WP9 CL1 8.
10.		 0.9
1.1		      
WP9 CL3 8.
10.		 0.9
1.1		      
WPR     1.6
2.24		 0.75
1.25		  
WP91 8.
9.5		 0.85
1.05		 0.4
max		   V 0.18
0.25
Nb 0.06
0.1
N 0.03
0.07
Al 0.02 max (6)
Ti 0.01 max (6)
Zr 0.01 max (6)
WP911 8.
9.5		 0.9
1.1		 0.4
max		   V 0.18
0.25
Nb 0.06
0.1
N 0.04
0.09
Al 0.02 max (6)
B 0.0003
0.006
W 0.9
1.1
Ti 0.01 max (6)
Zr 0.01 max (6)

ASTM A182

Specification for Alloy Steel Forgings for Piping Applications

Identification Symbol UNS Designation C Mn P S Si Cr Ni Mo Other Elements
F 1 K12822 0.28 0.6-0.9 0.045 0.045 0.15-0.35     0.44-0.65           
F 2B K12122 0.05-0.21 0.3-0.8 0.04 0.04 0.1-0.6 0.5-0.81   0.44-0.65           
F 5C K41545 0.15 0.3-0.6 0.03 0.03 0.5 4.0-6.0 0.5 0.44-0.65           
F 5aC K42544 0.25 0.6 0.04 0.03 0.5 4.0-6.0 0.5 0.44-0.65           
F 9 K90941 0.15 0.3-0.6 0.03 0.03 0.5-1 8.0-10.0   0.9-1.1           
F 10 S33100 0.1-0.2 0.5-0.8 0.04 0.03 1-1.4 7.0-9.0 19-22             
F 91 K90901 0.08-0.12 0.3-0.6 0.02 0.01 0.2-0.5 8-9.5 0.4 0.85-1.05 N[0.03-0.07]  Al [0.02D]
Ti [0.01D]
Cb [0.06-0.1]   V [0.18-0.25]
Zr [0.01D]  
F 92 K92460 0.07-0.13 0.3-0.6 0.02 0.01 0.5 8.5-9.5 0.4 0.3-0.6 N[0.03-0.07]  Al [0.02D]
Ti [0.01D]
Cb[0.04-0.09] B [0.001-0.006]
W [1.5-2.0]
 V [0.15-0.25] Zr [0.01D]  
F 122 K91271 0.07-0.14 0.7 0.02 0.01 0.5 10-11.5 0.5 0.25-0.6 N[0.04-0.1] Cu [0.3-1.7] Al [0.02D]
Ti [0.01D]
 Cb [0.04-0.1] B [0.005]
W [1.5-2.5]
 V [0.15-0.3] Zr [0.01D]  
F 911 K91061 0.09-0.13 0.3-0.6 0.02 0.01 0.1-0.5 8.5-9.5 0.4 0.9-1.1 N[0.04-0.09]  Al [0.02D]
Ti [0.01D]
Cb [0.06-0.1] B [0.0003-0.006]
W [0.9-1.1]
V [0.18-0.25] Zr [0.01D]  
F 11 K11597 0.05-0.15 0.3-0.6 0.03 0.03 0.5-1.0 1-1.5   0.44-0.65           
Class 1
F 11 K11572 0.1-0.2 0.3-0.8 0.04 0.04 0.5-1.0 1-1.5   0.44-0.65           
Class 2
F 11 K11572 0.1-0.2 0.3-0.8 0.04 0.04 0.5-1.0 1-1.5   0.44-0.65           
Class 3
F 12 K11562 0.05-0.15 0.3-0.6 0.045 0.045 0.5 max 0.8-1.25   0.44-0.65           
Class 1
F 12 K11564 0.1-0.2 0.3-0.8 0.04 0.04 0.1-0.6 0.8-1.25   0.44-0.65           
Class 2
F 21 K31545 0.05-0.15 0.3-0.6 0.04 0.04 0.5 max 2.7-3.3   0.8-1.06           
F 3V K31830 0.05-0.18 0.3-0.6 0.02 0.02 0.1 2.8-3.2   0.9-1.1  Ti [0.015-0.035]
B [0.001-0.003]
V [0.2-0.3]   
F 3VCb K31390 0.1-0.15 0.3-0.6 0.02 0.01 0.1 2.7-3.3 0.25 0.9-1.1  Cu [0.25] 
Ti [0.015]
Cb [0.015-0.07]
 V [0.2-0.3]
 Ca [0.0005–0.0150] 
F 22 K21590 0.05-0.15 0.3-0.6 0.04 0.04 0.5 2.0-2.5   0.87-1.13           
Class 1
F 22 K21590 0.05-0.15 0.3-0.6 0.04 0.04 0.5 2.0-2.5   0.87-1.13           
Class 3
F 22V K31835 0.11-0.15 0.3-0.6 0.015 0.01 0.1 2.0-2.5 0.25 0.9-1.1 Cu [0.2] 
Ti [0.03]
Cb [0.07]
B [0.002]
 V [0.25-0.35] Ca [0.015E] 
F 23 K41650 0.04-0.1 0.1-0.6 0.03 0.01 0.5 1.9-2.6 0.4 0.05-0.3 N[0.015F] 
Al [0.03]
Ti [0.005-0.06F]
Cb [0.02-0.08]
B [0.001-0.006]
W [1.45-1.75] V [0.2-0.3]   
F 24 K30736 0.05-0.1 0.3-0.7 0.02 0.01 0.15-0.45 2.2-2.6   0.9-1.1 N[0.12] 
Al [0.02]
 Ti [0.06-0.1]  B [0.0015-0.007] 
V [0.2-0.3]   
FR K22035 0.2 0.4-1.06 0.045 0.05     1.6-2.24    Cu [0.75-1.25]         
F 36 K21001 0.1-0.17 0.8-1.2 0.03 0.025 0.25-0.5 0.3 1-1.3 0.25-0.5 N[0.02]
Cu [0.5-0.8]
Al [0.05]    
V [0.02]   
Grade Symbol Tensile Strength,
min, ksi [MPa]		 Yield Strength, min,
ksi [MPa]B 		Elongation in 2 in.
[50 mm] or 4D,
min, %		 Reduction of
Area, min, %		 Brinell Hardness
Number, HBW,
unless otherwise
indicated
F 1 70 [485] 40 [275] 20 30 143–192
F 2 70 [485] 40 [275] 20 30 143–192
F 5 70 [485] 40 [275] 20 35 143–217
F 5a 90 [620] 65 [450] 22 50 187–248
F 9 85 [585]   55 [380] 20 40  179–217
F 10 80 [550] 30 [205] 30 50 . . .
F 91 90 [620]  60 [415] 20 40 190–248
F 92 90 [620]  64 [440] 20 45 269 max
F 122 90 [620]  58 [400] 20 40 250 max
F 911 90 [620]  64 [440] 18 40 187–248
F 11
Class 1		 60 [415] 30 [205] 20 45  121–174
F 11
Class 2		 70 [485] 40 [275] 20 30 143–207
F 11
Class 3		 75 [515] 45 [310] 20 30 156–207
F 12
Class 1		 60 [415] 32 [220] 20 45 121–174
F 12
Class 2		  70 [485] 40 [275] 20 30 143–207
F 21  75 [515]  45 [310] 20 30 156–207
F 3V & F 3VCb 85–110 [585–760] 60 [415] 18 45 174–237
F 22
Class 1		  60 [415]  30 [205] 20 35  170 max
F 22
Class 3		  75 [515]  45 [310] 20 30 156–207
F 22V 85–110 [585–780] 60 [415] 18 45  174–237
F 23  74 [510]  58 [400] 20 40  220 max
F 24  85 [585] 60 [415] 20 40 248 max
FR 63 [435] 46 [315] 25 38 197 max
F 36 Class 1  90 [620] 64 [440] 15 . . . 252 max
F 36 Class 2 95.5 [660]  66.5 [460] 15 . . . 252 max
AISI/SAE grade UNS DIN EN steel number EN steel name BS UNI JIS
(USA) (USA) (Germany) (Europe) (Europe) (UK) (Italy) (Japan)
4130   25CrMo4 1.7218   708A30 25CrMo4 (KB) SCM 420
GS-25CrMo4 CDS110 30CrMo4 SCM 430
      SCCrM1
4140/4142   41CrMo4 1.7223 42CrMo4 708M40 41CrMo4 SCM 440
42CrMo4 1.7225 708A42 38CrMo4 (KB) SCM 440H
42CrMoS4 1.7227 709M40 G40 CrMo4 SNB 7
43CrMo4 1.3563 En19 42CrMo4 SCM 4M
    En19C   SCM 4
4340   34CrNiMo6 1.6582 34CrNiMo6 817M40 35NiCrMo6 (KB) SNCM 447
40NiCrMo8-4 1.6562 En24 40NiCrMo7 (KB) SNB24-1-5
8620   21NiCrMo22 1.6543 20NiCrMo2-2 805A20 20NiCrMo2 SNCM 200 (H)
21NiCrMo2 1.6523 805M20
  K12822 15Mo3 1.5415 16Mo3 1503-243B 15Mo3 STBA12
K12320 240 16Mo3
K12020 243  
K11820    
F 5/F 5A K 41545 12CrMo195          
F 9 K 90941 X12CrMo91          
F 11 (CL2) K 11572 13CrMo44          
F 22 (CL3) K 21590 10CrMo910          
F 91   X10CrMoVNb9-1          
Hiton Fittings Pvt. Ltd.