A240 SS321H Steel Plate Applications & Ordering Guide

ASTM A240 / ASME SA240 Type 321H (UNS S32109) is specified for industrial fabrications where the drawing or material list names this grade. This applications page explains where the grade is used, what service conditions drive selection, and which certificate details belong on the purchase order. Gangsteel supplies ASTM A240 / ASME SA240 Type 321H with EN 10204 mill test certificates.

Typical Applications and Service Conditions

ASTM A240 / ASME SA240 Type 321H plate is ordered for pressure equipment, process vessels, heat-exchanger related fabrications, structural members under the governing code, and project packages that call the grade by name. Match the mill test certificate grade mark to the calculation sheet; do not treat near-equivalents as automatic substitutes.

Service drivers include the design temperature and pressure of the governing code (ASME, EN/PED, class society, or project specification), weld procedure qualification needs, toughness or creep allowables where applicable, and inspection scope. Delivery condition Solution annealed; ASTM grain size No. 7 or coarser for H grades should be stated explicitly on the purchase order.

Industry Use Cases

Pressure equipment and process: shells, heads, and related platework when drawings name ASTM A240 / ASME SA240 Type 321H. Power and energy: boiler and heat-recovery fabrications under the ordered edition. Marine / offshore (when classed): only when the society material list names this exact grade stamp. Always keep heat-number traceability on cut pieces.

Chemical Composition - Supporting Data (ASTM A240 / ASME SA240 Type 321H)

Ti min = 4x(C+N), max 0.70% (H-grade rule). Grain size No. 7 or coarser for austenitic H grades.

Element	Min %	Max % / requirement
C	0.04	0.10
Mn	-	<=2.00
Si	-	<=0.75
P	-	<=0.045
S	-	<=0.030
Cr	17.0	19.0
Ni	9.0	12.0
Ti	4x(C+N)	0.70

Mechanical Properties - Supporting Data (ASTM A240 / ASME SA240 Type 321H)

Confirm thickness, specimen orientation, and any supplementary impact, UT, or hardness requirements on the PO.

Property	Requirement
Tensile strength, min	515 MPa (75 ksi)
Yield strength (0.2% offset), min	205 MPa (30 ksi)
Elongation in 50 mm, min	40%
Hardness, max	217 HBW / 95 HRB
Delivery condition	Solution annealed

Related / Near-Equivalent Grades

Near-equivalents are for cross-reference only. They are not automatic code substitutes. Substitution requires engineer approval and matching certificate scope.

System	Grade	Note
ASME	SA240 Type 321H	ASME twin
ASTM	Type 321 / 347H	Stabilized / Nb-stabilized relatives
UNS	S32109	321H designation

Frequently Asked Questions

Where is ASTM A240 / ASME SA240 Type 321H typically applied?

ASTM A240 / ASME SA240 Type 321H is applied where design documents, class material lists, or purchaser specs name this grade for pressure, process, structural, or marine fabrications as applicable. Match the MTC marking to the drawing.

What service conditions drive selection of ASTM A240 / ASME SA240 Type 321H?

Design temperature and pressure, toughness or creep allowables, weldability, corrosion or process media, and the governing code edition drive selection. Delivery condition Solution annealed; ASTM grain size No. 7 or coarser for H grades must align with the ordered specification.

Can a near-equivalent replace ASTM A240 / ASME SA240 Type 321H on an applications drawing?

Not without redesign and written approval. Near-equivalents differ in chemistry, heat treatment, impact temperature, or product form. Commercial swaps create non-conformance when the dossier names ASTM A240 / ASME SA240 Type 321H.

What fabrication notes matter for ASTM A240 / ASME SA240 Type 321H?

Use approved WPS/PQR packages for the thickness and filler, control heat input, and preserve heat-number traceability on cut pieces. State any supplementary UT, PMI, or impact tests on the purchase order.

What certificate and marking should an applications PO demand?

EN 10204 3.1 is standard; 3.2 when a purchaser-appointed inspector witnesses tests. The MTC should show heat analysis, tensile results, delivery condition, and heat number aligned with ASTM A240 / ASME SA240 Type 321H.

How should I RFQ ASTM A240 / ASME SA240 Type 321H plate from Gangsteel for a project?

Send ASTM A240 / ASME SA240 Type 321H (UNS S32109), thickness x width x length (or nesting list), quantity, delivery condition, optional NDT/PMI, certificate type, destination, and any dual-mark needs. Note the end use when special flatness or cut-to-size packaging is required.

Ordering and Mill Certificates

State grade ASTM A240 / ASME SA240 Type 321H (UNS S32109), dimensions, quantity, delivery condition, optional NDT/PMI, and certificate (EN 10204 3.1 standard; 3.2 when third-party inspection is ordered). Gangsteel supplies export plate and related products with mill test certificates. Contact Gangsteel for stock and mill production RFQs.