Project Description

Ⅰ. Overview of ASTM A387 Chromoly Steel Plate:

ASTM A387 specification covers chromium-molybdenum alloy steel plates intended primarily for welded boilers and pressure vessels designed for elevated temperature service.

 

Ⅱ. Maximum Thickness

The maximum thickness of plates is limited only by the capacity of the composition to meet the specified mechanical property requirements.

 

Ⅲ. Chemical Requirements of  ASTM A387 Chromoly Steel Plate

Chemical Requirements for ASTM A387 Pressure Vessel Plates
Elements
Gr.2
Gr.12
Gr.11
Gr.22
Gr.22L
Gr.21
Gr.21L
Gr.5
Gr.9
Gr.91
S50460
K11757
K11789
K21590
K21590
K31545
K31545
S50200
K90941
K90901
Carbon, max
  Heat Analysis
0.05-0.21
0.05-0.17
0.05-0.17
0.05-0.15A
0.10 max
0.05-0.15A
0.10 max
0.15 max
0.15 max
0.08-0.12
  Product Analysis
0.04-0.21
0.04-0.17
0.04-0.17
0.04-0.15A
0.12 max
0.04-0.15A
0.12 max
0.15 max
0.15 max
0.06-0.15
Manganese
  Heat Analysis
0.55-0.80
0.40-0.65
0.40-0.65
0.30-0.60
0.30-0.60
0.30-0.60
0.30-0.60
0.30-0.60
0.30-0.60
0.30-0.60
  Product Analysis
0.50-0.88
0.35-0.73
0.35-0.73
0.25-0.66
0.25-0.66
0.25-0.66
0.25-0.66
0.25-0.66
0.25-0.66
0.25-0.66
Phosphorous, max
  Heat Analysis
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.020
  Product Analysis
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
Sulfur, max
  Heat Analysis
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.010
  Product Analysis
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.025
0.012
Silicon
  Heat Analysis
0.15-0.40
0.15-0.40
0.50-0.80
0.50 max
0.50 max
0.50 max
0.50 max
0.50 max
1.00 max
0.20-0.50
  Product Analysis
0.13-0.45
0.13-0.45
0.44-0.86
0.50 max
0.50 max
0.50 max
0.50 max
0.55 max
1.05 max
0.18-0.56
Chromium
  Heat Analysis
0.50-0.80
0.80-1.15
1.00-1.50
2.00-2.50
2.00-2.50
2.75-3.25
2.75-3.25
4.00-6.00
8.00-10.00
8.00-9.50
  Product Analysis
0.46-0.85
0.74-1.21
0.94-1.56
1.88-2.62
1.88-2.62
2.63-3.37
2.63-3.37
3.90-6.10
7.90-10.10
7.90-9.60
Molybdenum
  Heat Analysis
0.45-0.60
0.45-0.60
0.45-0.60
0.90-1.10
0.90-1.10
0.90-1.10
0.90-1.10
0.45-0.65
0.90-1.10
0.85-1.05
  Product Analysis
0.40-0.65
0.40-0.65
0.40-0.70
0.85-1.15
0.85-1.15
0.85-1.15
0.85-1.15
0.40-0.70
0.85-1.15
0.80-1.10
Nickel, max
  Heat Analysis
0.40
  Product Analysis
0.43
Vanadium
  Heat Analysis
0.04 max
0.18-0.25
  Product Analysis
0.05 max
0.16-0.27
Columbium
  Heat Analysis
0.06-0.10
  Product Analysis
0.05-0.11
Boron
  Heat Analysis
  Product Analysis
Nitrogen
  Heat Analysis
0.030-0.070
  Product Analysis
0.025-0.080
Aluminum, max
  Heat Analysis
0.02
  Product Analysis
0.02
Titanium, max
  Heat Analysis
0.01
  Product Analysis
0.01
Zirconium, max
  Heat Analysis
0.01
  Product Analysis
0.01
A The carbon content for plates over 5 in. [125 mm] in thickness is 0.17 max on product analysis

 

Ⅳ. Tensile Requirements

Tensile Requirements for ASTM A387 Class 1 Pressure Vessel Plates
Grade 2 and 12
Grade 11
Grade 22, 21, 5, 9, 21L, 22L
Tensile Strength
Ksi(Mpa)
55~80
(380~550)
60~85
(415~585)
60~85
(415~585)
Yield Strength, min
Ksi(Mpa)
33(230)
35(240)
30(205)
Elongation in 8 in.[200mm], min, %
18
19
Elongation in 2 in.[50mm], min, %
22
22
18
Reduction of area, min, %
45B
40C

 

Tensile Requirements for ASTM A387 Class 2 Pressure Vessel Plates
Grade 2
Grade 11
Grade 12
Grade 22, 21, 5, 9
Grade 91
Tensile Strength
Ksi(Mpa)
70~90
(485~620)
75~100
(515~690)
65~85
(450~585)
75~100
(515~690)
85~110
(585~760)
Yield Strength, min
Ksi(Mpa)
45(310)
45(310)
40(275)
45(310)
60(415)
Elongation in 8 in.[200mm], min, %
18
18
19
Elongation in 2 in.[50mm], min, %
22
22
22
18
18
Reduction of area, min, %
45B
40C

B: Measured on round test specimens.
C: Measured on flat specimen.

 

Ⅴ. Heat Treatment

1. Except for Grade 91, all plates shall be thermally treated either by annealing, normalizing- and -tempering, or, when permitted by the purchaser, accelerated cooling from the austenitizing temperature by air blasting or liquid quenching, followed by tempering. Minimum tempering temperatures shall be as follows:

Grade
Temperature, °F [°C]
2, 12, 11
1150 (620)
22, 22L, 21, 21L, 9
1250 (675)
5
1300 (705)

2. Grade 91 plates shall be thermally treated, either by normalizing-and-tempering or by accelerated cooling from the austenitizing temperature by air blasting or liquid quenching, followed by tempering. Grade 91 plates shall be austenitized at 1900 to 1975°F [1040 to 1080°C] and shall be tempered at 1350 to 1470°F [730 to 800°C].

3. Grade 5, 9, 21, 21L, 22, 22L, and 91 plates ordered without the heat treatment required by item 2 and item 3 shall be furnished in either the stress-relieved or the annealed condition