ASTMA 403/A 403M: American Society for Testing and Materials
Wrought Austenitic Stainless Steel Piping Fittings
Scope: This specification covers wrought stainless steel fittings for pressure piping applications.

Chemical Composition

Identification  Symbol

Grade CR

UNS Designation

Composition, %

Carbon

Manganese

Phosphorus

Sulfur

Silicon

Nickel

Chromium

Molybdenum

Titanium

N2C

Other Elements

WP304

CR304

S30400

0.08

2

0.045

0.03

1

8.0±11.0

18.0±20.0

WP304H

CR304L

S30403

0.03

2

0.045

0.03

1

8.0±12.0

18.0±20.0

WP304L

CR304H

S30409

0.04±0.10

2

0.045

0.03

1

8.0±11.0

18.0±20.0

WP316

CR316

S31600

0.08

2

0.045

0.03

1

10.0±14.0

16.0±18.0

2.00±3.00

WP316L

CR316L

S31603

0.03

2

0.045

0.03

1

10.0±14.0

16.0±18.0

2.00±3.00

WP321

CR321

S32100

0.08

2

0.045

0.03

1

9.0±12.0

17.0±19.0

WP321H

CR321H

S32109

0.04±0.10

2

0.045

0.03

1

9.0±12.0

17.0±19.0

WP347

CR347

S34700

0.08

2

0.045

0.03

1

9.0±12.0

17.0±19.0

WP347H

CR347H

S34709

0.04±0.10

2

0.045

0.03

1

9.0±12.0

17.0±19.0

Mechanical Properties
All WP and CR Grades	Tensile Strength, min, ksi [MPa]	Yield Strength, min, ksi [MPa]
304, 304LN, 304H, 309,310, 316, 316LN, 316H,317, 317L, 321, 321H,347, 347H, 348, 348H	75 [515]	30 [205]
S31725
304L, 316L	70 [485]	25 [170]
304N, 316N, S31726	80 [550]	35 [240]
XM-19	100 [690]	55 [380]
S31254	94 [650] to 119 [820]	44 [300]
S33228	73 [500]	27 [185]
S34565	115 [795]	60 [415]

Elongation Requirements
Standard round specimen, or small proportional specimen, or strip-type specimen, minimum % in 4D	Longitudinal	Transverse
	28	20

Fitting Classes for WP Grades
Class	Construction	Nondestructive Examination
S	Seamless	None
W	Welded	Radiography or Ultrasonic
WX	Welded	Radiography
WU	Welded	Ultrasonic

1.1 This specification covers wrought stainless steel fittings for pressure piping applications.
1.2 Several grades of austenitic stainless steel alloys are included in this specification Grades are designated with a prefix, WP or CR, based on the applicable ASME or MSS dimensional and rating standards, respectively.
1.3 For each of the WP stainless grades, several classes of fittings are covered, to indicate whether seamless or welded construction was utilized. Class designations are also utilized to indicate the nondestructive test method and extent of nondestructive examination (NDE). Table 1 is a general summary of the fitting classes applicable to all WP grades of stainless steel covered by this specification. There are no classes for the CR grades. specification requirements are covered elsewhere.