SUS321 Stainless Steel

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We are the leading supplier Malaysia of SS321 / 1.4542 Stainless Steel.  Stainless Steel Grade 321 and SUS347 are the basic austenitic 18/8 steel (SUS304) stabilised by Titanium (SUS321) or Niobium (SUS347) additions.

With the strong global sourcing in 904L Stainless Steel, our sales and supplier network including : Australia, Pakistan,  Malaysia, Singapore, Taiwan, China, Vietnam, Belgium, Japan, South Korea, Philippines, France, United Kingdom, Indonesia, Thailand, Hong Kong, China, Sweden, United States, Dubai, Finland, Brunei, Germany.


Leading Supplier of Stainless Steel 321

Specifications of Grade 321 Stainless Steel also equivalent to 
  • SUS321 | SS321 | UNS S32100 | 1.4541


Properties of SUS321 Stainless Steel

Stainless Steel Grade 321 (SUS321) and Stainless Steel Grade 347 (SUS347) are the basic austenitic 18/8 steel (SUS304) stabilised by Titanium (SUS321) or Niobium (SUS347) additions. These grades are used because they are not sensitive to inter-granular corrosion after heating within the carbide precipitation range of 425-850°C.

SS321 (Stainless Steel Type 321) is the grade of choice for applications in the temperature range of up to about 900°C, combining high strength, resistance to scaling and phase stability with resistance to subsequent aqueous corrosion.

SUS321H is a modification of SUS 321 with higher carbon content, to provide improved high-temperature strength.

A limitation with SUS321 is that titanium does not transfer well across a high temperature arc, so is not recommended as a welding consumable. In this case SUS 347 is preferred – the niobium performs the same carbide stabilization task but can be transferred across a welding arc. SS347 is, therefore, the standard consumable for welding SS 321. SS 347 is only occasionally used as parent plate material.

Like other austenitic grades, Grade 321 and Grade 347 Stainless Steel have excellent forming and welding characteristics, are readily brake or roll formed and have outstanding welding characteristics. Post-weld annealing is not required. They also have excellent toughness, even down to cryogenic temperatures. SUS321 does not polish well, so is not recommended for decorative applications.

Grade 304L Stainless Steel (SUS304L) is more readily available in most product forms, and so is generally used in preference to 321 if the requirement is simply for resistance to intergranular corrosion after welding. However, SUS304L has lower hot strength than SUS321 and so is not the best choice if the requirement is resistance to an operating environment over about 500°C.


Chemical Formula of SUS 321 Stainless Steel

Fe | <0.08% C | 17-19% Cr | 9-12% Ni | <2% Mn | <1% Si | 0.3-0.7% Ti | <0.045% P | <0.03% S


Key Properties 

These properties are specified for flat rolled product (plate, sheet and coil) in ASTM A240/A240M. Similar but not necessarily identical properties are specified for other products such as pipe and bar in their respective specifications.

Grade CMnSiPSCrMoNiN
SUS 310min. -----24.0-19.0-
SUS 310Smin. -----24.0-10.0


Mechanical Properties for SS321 

GradeTensile Strength (MPa) minYield Strength 0.2% Proof (MPa) minElongation (% in 50mm) minHardness
Rockwell B (HR B) maxBrinell (HB) max
SUS 3215152054095217
SUS 321H5152054095217
SUS 3475152054092201

* SUS 321H also has a requirement for a grain size of ASTM No 7 or coarser.


Physical Properties for SS 321 

GradeDensity (kg/m3)Elastic Modulus (GPa)Mean Coefficient of Thermal Expansion (mm/m/°C)Thermal Conductivity (W/m.K)Specific Heat 0-100°C (J/kg.K)Electrical Resistivity (nW.m)
0-100°C0-315°C0-538°Cat 100°Cat 500°C


Corrosion Resistance for UNS S32100 Stainless Steel

Equivalent to SUS304 in the annealed condition, and superior if a weldment in these grades has not been post-weld annealed or if the application involves service in the 425-900°C range.

Subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above about 60°C. Considered resistant to potable water with up to about 200mg/L chlorides at ambient temperatures, reducing to about 150mg/L at 60°C.


Heat Resistance for SUS 321 Stainless Steel 

Good oxidation resistance in intermittent service to 900°C and in continuous service to 925°C. These grades perform well in the 425-900°C range, and particularly where subsequent aqueous corrosive conditions are present.

SUS321H has higher hot strength and is particularly suitable for high-temperature structural applications.


Heat Treatment for SS321 Stainless Steel (1.4541) 

Solution Treatment (Annealing)

heat to 950-1120°C and cool rapidly for maximum corrosion resistance.


heat to 870-900°C for 1 hour per 25mm of thickness and air cool. Stabilization is recommended for most severe service conditions (above 425°C) and particularly for material annealed at the upper side of the annealing temperature range.

Stress Relief

Heat to 700°C for 1 to 2 hours and air cool.

* These grades cannot be hardened by thermal treatment.


Excellent weldability by all standard fusion methods, both with and without filler metals. AS 1554.6 pre-qualifies welding of SUS321 and SUS347 with Type 347 Stailess Steel rods or electrodes; high silicon version of SUS 347 is also pre-qualified for welding of SUS 321.


Comparison of SUS321 Stainless Steel (UNS S32100)

GradeUNS NoOld BritishEuronorm Swedish SSJapanese JIS
SS321S32100321S3158B, 58C1.4541X6CrNiTi18-102337SUS 321
SS321HS32109321S51-1.4878X10CrNiTi18-10-SUS 321H
SS347S34700347S3158G1.4550X6CrNiNb18-102338SUS 347

* These comparisons are approximate only. The list is intended as a comparison of functionally similar materials, not as a schedule of contractual equivalents. If exact equivalents are needed original specifications must be consulted.


Possible Alternative Grades to Grade 321 Stainless Steel

GradeWhy it might be chosen instead of 321
SS304LThe requirement is for resistance to intergranular corrosion, not for high temperature strength
3CR12Only mild “high temperature” environment is present… up to about 600°C.
SS304HOnly mild “high temperature” environment is present… up to about 800°C.
SS310The temperature of the operating environment is up to about 1100°C – too high for 321 or 321H.
The temperature of the operating environment is up to about 1150°C- too high for 321 or 321H.


Technical Applications in Type 321 Stainless Steel 

SUS321 Stainless Steel can be used in the following applications : 

  • Furnace parts
  • Oil burner parts
  • Carburising boxes
  • Heat Treatment baskets and jigs
  • Heat Exchangers
  • Welding filler wire and electrodes


Our Sales and Supplier Network in SUS321 / SS321 / 321 Grade Stainless Steel : 

With over 15 years of experience and strong global sourcing networking in the market, we are proud to be the SUS 321 Stainless Steel Supplier and Exporter to :

  • Australia, Pakistan,  Malaysia, Singapore, Taiwan, China, Vietnam, Belgium, Japan, South Korea, Philippines, France, United Kingdom, Indonesia, Thailand, Hong Kong, China, Sweden, United States, Dubai, Finland, Brunei, Germany.

Besides, we have the full range of Stainless Steel sheets, Stainless Steel Round Bar, Stainless Steel Rods, Stainless Steel Plate which consists of 

300 Series Stainless Steel : SUS304, SUS304L, SUS309, SUS310, SUS316Ti, SUS317, SUS321, SUS347

400 Series Stainless Steel  : SUS403, SUS410, SUS420, SUS431, SUS440C, SUS630, SUS904L 

Nitronic 30, Nitronic 50, Nitronic 60

– Super Duplex S32750, S32760 


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