What is ASTM A358 Gr321 Cl 1 welded pipe?

What is ASTM A358?

ASTM A358 is a standard specification developed by the American Society for Testing and Materials (ASTM) for electric-fusion-welded (EFW) austenitic chromium-nickel stainless steel pipe intended for high-temperature service and general corrosive environments.

 

What is ASTM A358 Gr321 Cl 1 welded pipe?

ASTM A358 Grade 321 Class 1 welded stainless steel pipe is manufactured using the electric-fusion-welded (EFW) process. The material, based on TP321 (UNS S32100), is stabilized with the addition of titanium; this reduces the risk of chromium carbide precipitation-a phenomenon that typically occurs within the sensitization temperature range of approximately 425–850°C. The pipe features double-sided welds produced with the use of filler metal and undergoes 100% radiographic testing (RT). Following welding, the pipe is subjected to a solution heat treatment in accordance with standard requirements to improve the microstructural uniformity and corrosion resistance of the weld zone. This product is suitable for industrial piping systems operating in high-temperature or corrosive environments where stringent weld quality standards are required.

 

ASTM A358 Gr321 Cl 1 welded pipe Specification

Item	Detail
Standard	ASTM A358/A358M
Grade	321 (UNS S32100)
Class	Class 1
Manufacturing Process	Electric Fusion Welded (EFW)
Welding Method	Double-welded butt joint, filler metal in all passes
Radiography	100% complete radiographic examination (RT) of all welds
OD Range	8" NB – 110" NB (DN200 – DN2800)
Wall Thickness	Schedule 10 – Schedule 160 (3 mm – 100 mm)
Dimension Standard	ASME B36.19M / B36.10M
Application	High-temperature service, corrosive service, refinery piping, FGD systems, power generation

 

Chemical Composition (wt%)

Element	Min	Max
Carbon (C)	-	0.08
Manganese (Mn)	-	2.00
Phosphorus (P)	-	0.045
Sulfur (S)	-	0.030
Silicon (Si)	-	0.75
Chromium (Cr)	17.0	19.0
Nickel (Ni)	9.0	12.0
Titanium (Ti)	5 × (C + N)	0.70
Nitrogen (N)	-	0.10
Iron (Fe)	-	Balance

 

Mechanical Properties

Property	Requirement	Test Standard
Tensile Strength	≥ 515 MPa (75 ksi)	ASTM E8/E8M
Yield Strength (0.2% offset)	≥ 205 MPa (30 ksi)	ASTM E8/E8M
Elongation	≥ 35%	ASTM E8/E8M
Hardness (max)	201 HB	-

 

Heat Treatment

Parameter	Requirement
Annealing Temperature	1900 °F [1040 °C] min (for Grade 321)
Cooling	Water quench or equivalent rapid cooling (sufficient to prevent carbide re-precipitation)
Stabilization (S5)	Optional stabilizing heat treatment at lower temperature for 321, 321H, 347, 347H, 348
Intergranular Corrosion	Shall pass Practice E of ASTM A262 (on sensitized specimens)

 

ANSI/ASME B36.10M B36.19M Dimension Comparison Table

Outside Diameter		Wall Thicknesses Schedule
DN(in)	D(mm)	SCH 10S	SCH 20	SCH STD	SCH 60	SCH XS	SCH 140	SCH 160	SCH XXS
6"	168.3	3.4	–	7.11	–	10.97	–	18.26	21.95
8"	219.1	3.76	–	8.18	10.31	12.7	20.62	23.01	22.23
10"	273.1	4.19	6.35	9.27	12.7	12.7	28.58	25.4	–
12"	323.9	4.57	6.35	9.53	14.27	12.7	28.58	33.32	25.4
14"	355.6	4.78	7.92	9.53	15.09	12.7	31.75	35.71	–
16"	406.4	4.78	7.92	9.53	16.66	12.7	36.53	40.49	–
18"	457.2	4.78	7.92	9.53	19.05	12.7	39.67	45.24	–
20"	508	5.54	9.53	9.53	20.62	12.7	44.45	50.01	–
22"	558.8	5.54	9.53	9.53	22.23	12.7	47.63	53.98	–
24"	609.6	6.35	9.53	9.53	24.61	12.7	52.37	59.54	–
26"	660.4	–	12.7	9.53	–	12.7	–	–	–
28"	711.2	–	12.7	9.53	–	12.7	–	–	–
30"	762	7.92	12.7	9.53	–	12.7	–	–	–
32"	812.8	–	12.7	9.53	–	12.7	–	–	–
34"	863.6	–	12.7	9.53	–	12.7	–	–	–
36"	914.4	–	12.7	9.53	–	12.7	–	–	–
38"	965.2	–	–	9.53	–	12.7	–	–	–
40"	1016	–	–	9.53	–	12.7	–	–	–
42"	1066.8	–	–	9.53	–	12.7	–	–	–
44"	1117.6	–	–	9.53	–	12.7	–	–	–
46"	1168.4	–	–	9.53	–	12.7	–	–	–
48"	1219.2	–	–	9.53	–	12.7	–	–	–

 

ASTM A358 Class Comparison

Class	Weld Type	Filler Metal	Radiography
Class 1	Double-welded	All passes	100% RT
Class 2	Double-welded	All passes	None
Class 3	Single-welded	All passes	100% RT
Class 4	Single-welded	Inside pass may omit filler	100% RT
Class 5	Double-welded	All passes	Spot RT (≥ 12 in. per 20 ft)

 

Our export case study: For an expansion project at a high-temperature petrochemical facility in Europe

No.	Type	Size (inch)	Schedule	Material Grade	Description	Mandatory Requirements	Unit Weight (kg/m)
1	EFW	12	SCH 160	ASTM A358 Gr. 321 Class 1	Pipe, EFW, 100% RT, BE, ASTM A358 Gr. 321 Class 1, ASME B36.10M	100% Radiographic Testing (RT)	241.18
2	EFW	10	SCH 160	ASTM A358 Gr. 321 Class 1	Pipe, EFW, 100% RT, BE, ASTM A358 Gr. 321 Class 1, ASME B36.10M	100% Radiographic Testing (RT)	174.08
3	EFW	8	SCH 160	ASTM A358 Gr. 321 Class 1	Pipe, EFW, 100% RT, BE, ASTM A358 Gr. 321 Class 1, ASME B36.10M	100% Radiographic Testing (RT)	112.39

If you are interested in purchasing ASTM A358 Grade 321 EFW stainless steel pipe, please provide the following information:Required outside diameter (OD) or nominal pipe size (NPS), wall thickness (Schedule or actual thickness), pipe length, and the required pipe class (Class 1 through 5) based on welding, heat-treatment, and inspection requirements.

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Testing & Inspection Requirements (Class 1)

Test	Requirement
Hydrostatic Test	Per ASTM A358 Clause 12 (all lengths)
Radiographic Examination (RT)	100% of all weld seams (Class 1 requirement)
Transverse Tension Test	Per ASTM E8/E8M
Transverse Guided-Bend Weld Test	Face and root bend (or side-bend for wall > 3/8" and < 3/4")
Product Analysis (S1)	Chemical analysis on each length (plate + weld) - optional

ASTM A358 TP321 Stainless Steel EFW Pipes Bundle packing

Packaging Details:	Plastic Caps: For small- to medium-diameter pipes (typically under 24"). Wooden Disks: For extra-large diameter EFW pipes (e.g., 30"–110"). Plywood Cases: For small- to medium-sized pipes with thin walls, polished surfaces, or strict export requirements. Steel Frames: For large-diameter pipes with thin walls; internal cross-bracing may be added.
Delivery Detail:	7-15 days