ASTM A240 Type 321 Stainless Steel Plate & Sheet

As a professional stainless steel plate supplier and China Mill-Direct Supply / Mill Direct Exporter, SHH STEEL is pleased to present ASTM A240 321 Stainless Steel Plate, also known as A240 Type 321.

ASTM A240 Type 321 is a titanium-stabilized austenitic chromium-nickel stainless steel. The addition of titanium stabilizes the carbon in the form of titanium carbides, effectively preventing the formation of chromium carbides at grain boundaries. This gives Type 321 outstanding resistance to intergranular corrosion after welding or after exposure to the sensitization temperature range (approximately 450–850°C). At the same time, the grade retains good general corrosion resistance, excellent toughness, and reliable mechanical properties at elevated temperatures.

Because of these characteristics, ASTM A240 321 is widely selected for welded equipment that operates at high temperature or that cannot receive post-weld solution annealing. It is commonly used in exhaust systems, heat exchangers, pressure vessels, expansion joints, and high-temperature process equipment.

SHH STEEL supplies ASTM A240 Type 321 as true Mill Direct Supply, sourcing directly from major Chinese stainless steel mills. This model provides competitive mill pricing, consistent quality, full heat traceability and shorter lead times. We offer thicknesses from 1 mm to 100 mm (thicker plates available on request), widths up to 2000–3000 mm, and lengths up to 12000 mm or cut-to-length. Material is normally supplied in the solution-annealed condition with No.1 or 2B finish, and other surface finishes can be arranged.

Heat Analysis (Ladle Analysis) according to ASTM A240 Type 321:

Product Analysis (typical permissible variations):

The minimum titanium content of five times the carbon content is the key stabilizing requirement. Titanium combines preferentially with carbon, preventing chromium carbide precipitation and thereby protecting the alloy from intergranular corrosion.

Room-Temperature Mechanical Properties (Annealed Condition)

Elevated-Temperature Behavior ASTM A240 Type 321 maintains useful strength at temperatures up to approximately 900°C and offers better resistance to sensitization than unstabilized 304 or 304H during continuous or intermittent high-temperature service.

Physical Properties

• Density: 7.93 g/cm³
• Melting Range: approximately 1400–1425°C
• Magnetic: Non-magnetic in the annealed condition

Type 321 is frequently chosen when the designer needs the sensitization resistance of a stabilized grade together with good high-temperature performance, without the higher cost of molybdenum-bearing alloys. When even higher elevated-temperature stability is required, astm a240 type 347 stainless steel sheet plate is often preferred. For general corrosion resistance with maximum weldability at lower temperatures, astm a240 type 304l stainless steel sheet plate remains the most economical choice. Japanese equivalent material is commonly supplied as jis g4305 sus321 steel plate.

In the annealed condition, ASTM A240 Type 321 offers corrosion resistance similar to Type 304 in most atmospheric, fresh-water and oxidizing environments. Its principal advantage is the excellent resistance to intergranular corrosion after welding or after exposure to the temperature range of 450–850°C.

It performs well in nitric acid and many organic media. Resistance to pitting and crevice corrosion in chloride environments is comparable to 304 and inferior to molybdenum-containing grades such as 316L or 316Ti. For combined high-temperature and chloride service, astm a240 type 316ti stainless steel sheet plate is frequently considered.

ASTM A240 Type 321 has excellent weldability by all standard fusion and resistance welding processes. Because the grade is titanium-stabilized, it can normally be used in the as-welded condition without risk of intergranular corrosion.

Matching or slightly over-alloyed filler metals (E347 / ER347) are recommended to maintain stabilization in the weld metal. Standard 308L fillers are sometimes used when the service temperature is moderate. Post-weld heat treatment is generally not required for corrosion resistance.

ASTM A240 Type 321 is supplied in the solution-annealed condition.

Recommended Solution Annealing Parameters

• Temperature: 950 – 1120°C (typically 1000 – 1100°C)
• Holding (soaking) time: – Plates ≤ 25 mm: minimum 10–20 minutes after the section reaches temperature – Plates 25–50 mm: minimum 20–40 minutes – Plates > 50 mm: 30–60 minutes or longer to ensure uniformity
• Cooling: Rapid cooling (water quench preferred for thicker sections) to retain the stabilized structure and maximum corrosion resistance

Stabilizing heat treatment (optional) at approximately 840–900°C for several hours can be applied in special cases to ensure complete titanium carbide precipitation, although modern melting practices usually make this unnecessary for most applications.

Dimensional tolerances conform to ASTM A240 and the general requirements of ASTM A480. Thickness, width, length and flatness are controlled within standard or tighter agreed limits.

Related grades commonly evaluated with ASTM A240 321 include astm a240 type 304 stainless steel sheet plate, astm a240 type 304l stainless steel sheet plate, astm a240 type 347 stainless steel sheet plate and jis g4305 sus321 steel plate.

ASTM A240 Type 321 is widely used in welded high-temperature and process equipment:

SHH STEEL is a China Mill-Direct Supply and Mill Direct Exporter of stainless steel plate. We maintain long-term cooperation with major Chinese mills and supply ASTM A240 Type 321 with the following advantages:

• Competitive mill-direct pricing
• Consistent quality and complete heat traceability
• Full Mill Test Certificates (EN 10204 3.1)
• Flexible dimensions and surface finishes
• Technical support for high-temperature material selection
• Reliable worldwide logistics and export documentation

ASTM A240 321 Stainless Steel Plate (A240 Type 321) is a titanium-stabilized austenitic stainless steel that combines excellent resistance to intergranular corrosion with reliable high-temperature performance. It is the material of choice for many welded structures and process equipment operating at elevated temperatures.

As a professional China Mill-Direct Supply and Mill Direct Exporter, SHH STEEL provides high-quality ASTM A240 Type 321 plate with competitive pricing, full certification and complete technical support.

Contact SHH STEEL today for stock availability, processing options or a competitive quotation.

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