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]

ASTM A420

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