QUALITY ASSURANCE

ASTM A420


Chemical Composition (%) of ASTM A420

Grade

C

Mn

P

S

Si

WPL6(1)(2)

0.3

0.60-1.35

0.035

0.04

0.15-0.30

WPL9

0.2

0.40-1.06

0.03

0.03

-


Grade

Ni

Cu

Cr

Mo

V

Nb

WPL6(1)(2)

0.4

0.4

0.3

0.12

0.08

0.02

WPL9

1.60-2.24

0.75-1.25

-

-

-

-


GENERAL NOTE:
All values are maximum unless otherwise indicated.

NOTES:
(1) For each reduction of 0.01% C below 0.30%, an increase of 0.05% Mn above 1.06% will be permitted, up to a maximum of 1.35%.
(2) Fittings made from forgings may have 1.35% max Mn.


Mechanical properties of ASTM A420

Tensile Requirements

WPL6

WPL9

Tensile Strength
min, ksi [MPa]

60-85[415-585]

63-88[435-610]

Yield Strength
min, ksi [MPa]

35[240]

46[315]


Where the wall thickness lies between two values above, the min elongation value is determined by the following equations:

WPL6,WPL9

Longitudinal E=48t+15.00,E=48t+13.00

Transverse E=32t+6.50,E=32t+8.00

E = elongation in 2in [50mm], %

t = actual thickness of specimen, in [mm]

Impact Test Properties

Since these pipe fittings are primarily used for low-temperature service, the properties of charpy V-notch impact test must be considered.

Charpy Impact Requirements for WPL6, WPL9, and WPL3


Size of Specimen

A*

B*

mm

ft·lbf

J

ft·lbf

J

10 by 10.0

13

17.6

10

13.6

10 by 7.5

10

13.6

8

10.8

10 by 5.0

7

9.5

5

7.0

10 by 2.5

4

5.4

3

4.1


A*Charpy V-Notch Impact Value Required for Acceptance (Average of Three Specimens)

B*Minimum Charpy V-Notch Impact Value Without Requiring Retest (One Specimen Only of a Set)Charpy Impact Requirements for WPL8


Size of Specimen

A*

B*

mm

ft·lbf

J

ft·lbf

J

10 by 10.0

25.0

33.9

20.0

27.1

10 by 7.5

21.0

28.5

17.0

23.1

10 by 5.0

17.0

23.1

14.0

19.0

10 by 2.5

8.0

10.8

6.0

8.1

A*Charpy V-Notch Impact Value Required for Acceptance (Average of Three Specimens)

B*Minimum Charpy V-Notch Impact Value Without Requiring Retest (One Specimen Only of a Set)


Impact Test Temperature

Grade

°F [°C]

WPL6

−50 [−45]

WPL9

−100 [−75]

WPL3

−150 [−100]

WPL8

−320 [−195]