• Metallica is one of the biggest stainless steel 321/321H product supplier and manufacturer in India, with over 250 customers in India and overseas. We are bulk buyers and exporters of stainless steel 321/321H pipes, fittings and flanges from our factory in India, and are able to give you the best price and quality just in time.
  • We stock all major forms of stainless steel 321/321H grade such as SS 321/321H pipe and tube, SS 321/321H forged flange and fittings, SS 321/321H butt-welding pipe fittings, SS 321/321H elbow, SS 321/321H tee, SS 321/321H reducer, SS 321/321H stub end, gaskets, fasteners, valves, sanitary fittings etc. Being one of the largest volume stainless steel 321/321H supplier in Mumbai, we can guarantee you the lowest prices.
  • At Metallica Metals, we believe in selling in volume and increasing our customer base across the globe, enabling us to work on low margins. We have an extensive trader network across India and the Middle East, who buy from us on a regular basis.
  • In addition to traders, we have many EPC contractors, companies and end users in various industries as our customers for stainless steel. We are leading stainless steel 321/321H suppliers for various applications ranging from low/medium/high pressure or temperatures.
  • Our company is a professional steel enterprise, specialized in steel plate, section steel, steel bar, stainless steel etc.
Stainless Steel 321/321H Supplier, Manufacturer, Distributor, Wholesaler in India and Overseas
  • Largest Stainless Steel 321/321H Products Supplier in India, with over 300 Tons in Stock

  • We Sell Stainless Steel 321/321H Products in Price Range of Rs. 200/KG to Rs. 600/KG.

  • Our Annual Sales Volume for Stainless Steel 321/321H Products is Over 1500 tons.

  • Stainless Steel 321/321H Pipes, are Sold with Complete Range of Related Pipe Fittings.

  • On-Time Delivery with Quality Assurance and Price Guarantee for Stainless Steel 321/321H.

What is SS 321/321H?

Stainless Steel 321 is a basic austenitic 18/8 steel (Grade 304) blend of chromium and nickel is stabilised by Titanium (321) addition. SS 321 is used because they are not sensitive to intergranular corrosion after heating within the carbide precipitation range of 425-850°C. Stainless Steel 321 is the grade of choice for applications in the temperature range of up to about 900°C, combining high strength, resistance to scaling, embrittlement and phase stability with resistance to subsequent aqueous corrosion. It is protected from temperatures ranging from 800 to 1500° F. The metal displays high strength and resistance to various forms of corrosions, including that from aqueous environments. Type 321 finds application in heavy welding components, along with dynamic environments that are subject to changes. Beyond this, stainless steel 321 has excellent forming characteristics, does not require annealing after being welded, and displays toughness in a range of temperatures. The metal shows strength even when exposed to cryogenic temperatures. Additionally, it is often chosen over Type 304 for its increased resistance to creep and rupture. Both metals may be susceptible to stress corrosion cracking. It is used to manufacture high quality carbon structural steel seamless steel tubes for hot rolling and cold drawing (rolling) of superheated steam pipe, boiling water pipe and locomotive boiler superheated steam pipe, large smoke pipe, small smoke pipe and arch brick.

SS 321H is a modification of SS 321 with a higher carbon content, to provide improved high temperature strength. In addition, 321H is stabilized by an addition of niobium to resist intergranular corrosion. It is also able to withstand higher temperatures than type 321, due to its elevated carbon levels. While 321H displays the same welding and forming characteristics of type 321, the metal cannot be hardened by heat treatment. It is utilized in situations where type 321 cannot withstand the high temperatures, typically those exceeding 1000° F. Type 321H displays better resistance against creep than both 321 and 304 stainless steels. 321H also shows resistance against acid corrosion in a variety of environments. Lower temperatures provide better resistance, but the metal is able to withstand up to a 10% acid solution, that has been diluted, at elevated temperatures. However, the metal shows very little resistance against chlorine or sulfuric solutions at any given temperature. Given their similar composition and characteristics, it is possible for stainless steels 321 and 321H to become dually certified.

What is the Difference Between SS 304, SS 316, SS 317, SS 321, SS 321H and SS 347?

The main variant of 321 is 321H which contains a higher quantity of carbon. 321 may contain up to 0.08% while 321H must contain between 0.04% and 0.08% carbon. The higher quantity of carbon confers greater strength at elevated temperatures. It is often chosen over Type 304 for its increased resistance to creep and rupture. 321 stainless steel is basically from 304 stainless steel. They differ by a very very small addition of Titanium. The real difference is their carbon content. The higher the carbon content the greater the yield strength. 321 stainless steel has advantages in high temperature environment due to its excellent mechanical properties. Compared with 304 alloy, 321 stainless steel has better ductility and resistance to stress fracture. In addition, 304L can also be used for anti-sensitization and intergranular corrosion.

Difference between 321 and other grades:

Type 304

The most common of austenitic grades, containing approximately 18% chromium and 8% nickel. It is used for chemical processing equipment, for food, dairy, and beverage industries, for heat exchangers, and for the milder chemicals.

Type 316

Contains 16% to 18% chromium and 11% to 14% nickel. It also has molybdenum added to the nickel and chrome of the 304. The molybdenum is used to control pit type attack. Type 316 is used in chemical processing, the pulp and paper industry, for food and beverage processing and dispensing and in the more corrosive environments. The molybdenum must be a minimum of 2%.

Type 317

Contains a higher percentage of molybdenum than 316 for highly corrosive environments. It must have a minimum of 3% “moly”. It is often used in stacks which contain scrubbers.

Type 317L

Restricts maximum carbon content to 0.030% max. and silicon to 0.75% max. for extra corrosion resistance.

Type 317LM

Requires molybdenum content of 4.00% min.

Type 317LMN

Requires molybdenum content of 4.00% min. and nitrogen of .15% min.

Type 321
Type 347

These types have been developed for corrosive resistance for repeated intermittent exposure to temperature above 800 degrees F. Type 321 is made by the addition of titanium and Type 347 is made by the addition of tantalum/columbium. These grades are primarily used in the aircraft industry.

Applications of 321/321H

  • For construction parts which should be resistant to scaling up to about 850°C and extensively inured to the effect of sulphurous gases. Inclination to carbonisation in reduced gases is very low.
  • Expansion joints
  • Chemical and Petrochemical processing
  • Pharmaceutical production
  • Waste treatment including thermal oxidizers
  • Equipment and storage units for Food processing
  • Aerospace Applications– piston engine manifolds
  • Food Processing – equipment and storage
  • Petroleum Refining – polythionic acid service
  • Exhaust Systems
  • Manifolds
  • Heat Exchangers
  • Piping
  • Furnace Parts
  • Chimney and Stack Liners
  • Storage Tanks
  • Bellows

Properties, Limitations and Processing Characteristics of Stainless Steel 321/321H


  • It is the second most commonly used stainless steel and represents around 20% of the entire world production of stainless steel.
  • Oxidation resistant to 1600°F
  • Stabilized against weld heat affected zone (HAZ) intergranular corrosion
  • Resists polythionic acid stress corrosion cracking
  • Excellent resistance oxidation to 1500°F (816°C)
  • Good low temperature toughness
  • Comparable corrosion resistance and machinability to Type 304
  • Readily welded by most standard processes
  • It is malleable and ductile and has good weldability.
  • Its austenitic structure allows it to be deep drawn without intermediate annealing. It is also unnecessary to anneal it following welding thin sections.
  • It is generally recommended that Stainless 347 is used for welding rods and electrodes. (347 employs niobium and tantalum in preference to titanium)
  • In its annealed state it is virtually non-magnetic even when cold worked, unlike 304 which can be significantly attracted to a magnet after cold working. This may make it more suitable in some applications.
  • It also maintains its strength down to cryogenic temperatures.
  • The key element that differentiates it from most other stainless steels is the inclusion of molybdenum, between 2% and 3%, which enhances its resistance corrosion in general and pitting corrosion in particular.


It is protected from temperatures ranging from 800 to 1500° F. The metal displays high strength and resistance to various forms of corrosions, including that from aqueous environments. Type 321 finds application in heavy welding components, along with dynamic environments that are subject to changes. The inclusion of molybdenum may have some adverse effects on its formability.

Processing / Welding

Alloy 321 stainless steel plate can be readily welded by most standard processes. A post weld heat treatment is not necessary. Standard welding processes for this steel grade are:

  •  TIG-Welding
  •  MAG-Welding Solid Wire
  •  Arc Welding (E)
  •  Laser Bean Welding

In quenched condition the material can be slightly magnetizable. With increasing cold forming the magnetizability increases.

Product Specification

Product TP321/321H, 1.4449/1.4438, UNS S31700/UNS31703 Stainless Steel

AISI 317, AISI 317L, ASTM A167, ASTM A182, ASTM A213, ASTM A240, ASTM A249, ASTM A269, ASTM A276, ASTM A312, ASTM A314, ASTM A403, ASTM A409, ASTM A473, ASTM A478, ASTM A511, ASTM A554, ASTM A580, ASTM A632, ASTM A813, ASTM A814, QQ S763, UNS S31700, UNS S31703, DIN 1.4438, ASTM A774, ASTM A778

  • 0Cr18Ni10Ti
  • The main variant of 321 is 321H which contains a higher quantity of carbon.
  • 347 is similar to 321 but uses Niobium in place of Titanium. Niobium easily forms very hard, extremely small grained carbides giving it even greater resistance to intergranular corrosion.
  • Titanium in 316Ti has broadly the same effect on 316, making it suitable where the performance required is similar to that of 321 but in a marine environment.
Type and Form Straight, Coiled, Seamless, Seam welded, cold redrawn and annealed

  • Tube
  • Pipe
  • Fittings
  • Flanges
  • Special Sections
  • Sheet
  • Plate
  • Flat Bar
  • Round Bar
  • Hollow Bar
  • Angles
  • i Beam
  • U Channel
End Plain End, Beveled End, Threaded
Length 6 Meter, Custom Lengths, Single Random, Double Random
Other Grades TP304, TP304L, TP304LN, TP316, TP316Ti, TP316H, TP316L, TP316LN, TP317, TP317/317L, TP321, TP347, TP310S
Test Certificates Material Test Certificates (MTC) as per EN 10204 3.1 and EN 10204 3.2
ASTM Reference Standards
  • A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels.
  • A370 Test Methods and Definitions for Mechanical Testing of Steel Products.
  • A480 A480M Specification for general requirements for Flat-rolled stainless and Heat-Resisting steel plate, sheet, and strip.
  • A632 Specification for Seamless and welded austenitic stainless-steel tubing (small-diameter) for general service.
  • A1016 A1016M Specification for General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless-Steel Tubes.
  • E527 Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS)
Testing Mechanical Testing Such as Tensile of Area, Hardness Test, Chemical Analysis – Spectro Analysis, Positive Material Identification – PMI Testing, Flattening Test, Micro and MacroTest, Pitting Resistance Test, Flaring Test, Intergranular Corrosion (IGC) Test
Documents Commercial Invoice, Packing List, Certificate of Origin, Fumigation Certificates, Raw Material Test Reports, Material Traceability Records, Quality Assurance Plan (QAP), Heat Treatment Charts, Test Certificates certifying NACE MR0103, NACE MR0175, Material Test Certificates (MTC) as per EN 10204 3.1 and EN 10204 3.2, Guarantee Letter, NABL approved Laboratory Test Reports

Chemical, Mechanical, Physical Properties and Creep Properties of 321/321H


UNS S32100 S32109
WERKSTOFF NR. 1.4878 1.4541

ASTM Specification

Pipe / Tube (SMLS) Sheet / Plate Bar Forging Fitting
A 213, A 249 A 167, A 240 A 276 A 182 A403

Chemical Composition

ELEMENT 321 321H
NI 9.0 – 12.0 9.0 – 12.0
C 0.08 max 0.04 – 0.10
MN 2.0 max 2.0 max
P 0.045 max 0.045 max
S 0.030 max 0.030 max
SI 1.0 max 1.0 max
CR 17.0 – 19.0 17.0 – 19.0
TI 5(C+N) – 0.70 max 4(C+N) – 0.70
N 0.10 max 0.10 max

Physical Properties

DENSITY 7.92 g/cm 3 / 0.286 lb/in 3
MELTING POINT 1398 – 1446 (°C) / 2550 – 2635 (°F)
ANNEALED 1040 – 1100 (°C) / 1900 – 2000 (°F)
QUENCH Rapid Air/Water
Coefficient of Thermal Expansion (min/in)-°F at 68 – 212°F 9.2
at 68 – 1832°F 20.5
Thermal Conductivity BTU/hr-ft-°F at 200°F 9.3
Specific Heat BTU/lbm -°F at 32 – 212°F 0.12
Modules of Elasticity (annealed)2-psi in tension (E) 28 x 10 ^6

Mechanical Properties

Grade Tensile Strength Yield Strength 0.2% Elongation – Hardness
ksi (min.) Offset ksi (min.) % in 50 mm (min.) (Brinell) MAX
321 75 30 40 217

Creep Properties

1% Elongation(1) for Rupture(2) for
Temperature °C 1,000 h N/mm2 10,000 h N/mm2 1,000 h N/mm2 10,000 h N/mm2 100,000 h N/mm2
600 110 85 200 142 65
700 45 30 88 48 22
800 15 10 30 15 10

Fabrication Data

Alloy 321 stainless steel plate can be easily welded and processed by standard shop fabrication practices.

Cold Forming

The alloy is quite ductile and forms easily.

Hot Forming

The high sulfur content of Alloy 303 also has a detrimental impact on hot workability. If hot forming is required, once again, 304 should be considered as an alternate selection.


The cold work hardening rate of 321 stainless steel plate makes it less machinable than 410 stainless steel, but similar to 304. The table below provides relevant machining data.

Heat Treatment and Resistance

321 resists oxidation up to 900oC in intermittent use and to 925oC in continuous use. It also avoids intergranular corrosion in the range 425 and 850oC.


Annealing at 1800-2000 F (928-1093 C) air cool. This process will result in maximum ductility. For maximum corrosion resistance, see the note on settled anneal under corrosion.


This alloy doesn’t harden by heat treating. High properties may only be obtained through cold reduction.

Corrosion Resistance

  • exhibits good general corrosion resistance that is comparable to 304.
  • developed for use in the chromium carbide precipitation range of 1800 – 1500°F (427 – 816°C) .
  • can be used in most diluted organic acids at moderate temperatures .
  • can be used in pure phosphoric acid at lower temperatures.
  • can be used in up to 10% diluted solutions at elevated temperatures.
  • resists polythionic acid stress corrosion cracking in hydrocarbon service.
  •  utilized in chloride or fluoride free caustic solutions at moderate temperatures.
  •  does not perform well in chloride solutions, even in small concentrations, or in sulfuric acid service.

Surface Treatment

  1. NO.1: surface treated with heat treatment and pickling after hot rolling.
    Generally used for cold rolling materials, industrial tank tanks, chemical industrial equipment, etc.
  2. NO.2D: matt cold rolled products obtained by heat treatment and pickling after cold rolling.
    Used for automobile parts, decoration materials, pipes, etc.
  3. NO.2B: NO.2D products after temperature-adjusted rolling have better gloss and flatness than NO.2D surfaces.
    The surface treatment with improved mechanical properties satisfies almost all USES.
  4. NO.3: NO.2D surface is ground by NO. 100~120 grinding band, with good gloss and discontinuous coarse grain.
    Used for interior and exterior decoration, electrical products and kitchen equipment, etc.
  5. NO.4: NO.2D surface after 150~320 abrasive belt grinding products, with better gloss and discontinuous coarse lines, stripes smaller than NO.3.
    Used for elevator decoration, kitchen equipment, interior and exterior decoration, electrical products, etc.
  6. HL: no.2d surface is continuously ground by polishing sand belt with appropriate particle size, and products with long continuous grinding stripes (subdivided 150~320).
    Mainly used for building decoration, elevator decoration, etc.
  7. BA: after cold rolling, a bright annealing is applied and the product is obtained through leveling.
    The surface has excellent gloss and high reflectance.
    It’s like a mirror surface.
    Used for household appliances, mirrors, kitchen equipment, decorative materials, etc.

Over 200 Tons in Stock for 321/321H Stainless Steel Products!

As one of the biggest 321/321H stainless steel stockholder and supplier in India, Metallica carries inventory of over 200 tons in its warehouses in Mumbai, Maharashtra India. We sell our 321/321H steel products throughout India, and to international clients.

How are Steel Pipes Certified?

Certification of Steel Pipes

Manufacturers issue a Material Test Report or Mill Test Report to validate that the product meets the chemical analysis and mechanical properties specification. The MTR will contain all relevant data to the product and will accompany the product through its lifecycle.

The following are typical parameters that may be recorded on an MTR:

  • Chemical composition including carbon content, alloys, and sulfur
  • Material size, weight, identification, and grade
  • Material heat number, which ties back to the processing batch
  • Mechanical properties like tensile strength, yield strength, and elongation

At Metallica, we will Provide you with Original MTR’s for all 321/321H Stainless Steel Pipe and its Related Products! We will Send Our Test Certificates, along with Quotation