Alloy Information For Type 321 Stainless Steel

Availability - Type 321 Stainless Steel

Seamless Stainless Steel Pipes 1/2" - 8"

Stainless Steel Tubes 1/2" - 8"

Weld Stainless Steel Pipes 1/2" - 12"

Stainless Steel Pipe Fittings 1/2" - 12"

Stainless Steel Flanges 1/2" - 12"

CHEMICAL ANALYSIS
C	Carbon .08 max
Mn	Manganese 2.00 max
P	Phosphorus 0.045 max*
S	Sulfur 0.30 max
Si	Silicon 1.00 max
Cr	Chromium 17.00 – 19.00
Ni	Nickel 9.00 – 12.00
N	Nitrogen .10 max
Ti	Titanium 5 x (C + N) min

GENERAL CHARACTERISTICS OF 321

Type 321 Stainless Steel is an austenitic stainless steel stabilized by additions of titanium to reduce or prevent carbide precipitation during welding and in service at 800 – 1650 º F (430 – 900 º C.) The titanium addition also improves high temperature properties. The grade has good resistance to corrosion and oxidation and good creep strength. Type 321 is good for applications at temperatures where carbide precipitation occurs in non – stabilized grades.

Type 321 stainless steel is a titanium – stabilized austenitic stainless steel that finds applications in a wide range of corrosive environments. It is particularly suited to applications where intermittent heating between 800 and 1650 º F (430 to 900 º C) is required.

FORGING TYPE 321 STAINLESS STEEL

Type 321 Stainless Steel has good inherent forgeability, but its differences from carbon and alloy steels must be taken into account. Type 321 has higher hot strength than carbon, alloy, even martensitic stainless steels, hence much higher forging pressures or more hammer blows are required to forge it – and other austenitic stainless steels. In fact two or three times as much energy is required to forge 300 series stainless steels as is required for carbon and alloy steels.

Type 321 Stainless Steel is forged between 2300 º F and 1700 º F (1260 º C and 930 º C,) and air cooled, but
to be more specific, a forging temperature coincident with forging conditions might be specified, as follows:

Severe reductions (ingot breakdown, roll forging, drawing, blocking, and backward extrusion)	2300 (1260)
Moderate reductions (finish forging and upsetting)	2200 (1200)
Slight reductions (coining, restriking and end upsetting)	2050 (1120)

APPLICATIONS

Airplane exhaust manifolds
Pump Shafts
Mechanical Seals
Heat Exchangers
Stainless Steel Pipe Fittings
Ball Valves
Stainless Steel Pipes
Boiler shells
Process equipment
Expansion joints
Cabin heaters
Fire walls
Flexible couplings
Pressure vessels
Stainless Steel Flanges (i.e. flanges, slip-ons, blinds, weld-necks, lapjoints, long welding necks, socket welds, elbows, tees, stub-ends, returns, caps, crosses, reducers, and pipe nipples)

HEAT TREATMENT

Type 321 stainless steel cannot be hardened by heat treatment, in fact the only heat treat operation that is performed on it is that of annealing, at around 1950 º F (1065 ºC,) followed by a water quench. This treatment gives maximum corrosion resistance for type 321 forgings.

MACHINABILITY

Type 321 Stainless Steel, like all austenitic stainless steels, machines to give tough, stringy chips. Chip breakers are recommended and since the alloy has a rapid work hardening rate, positive feeds are recommended.

WELDABILITY

Type 321 Stainless Steel may be welded by shielded fusion and resistance welding operations. Austenitic stainless steel welds do not harden on cooling, hence the welds will show good toughness.
Oxyacetylene welding is not recommended due to the possibility of carbon pick up in the weld area.
The alloy can be welded without loss of corrosion resistance due to carbide precipitation and the steel can be used in the as-welded condition. For use at elevated temperatures however, a postweld stabilizing heat treatment at 1550 – 1650 º F (840 – 900 º C) is recommended.

Source: Yaang Pipe Industry Co., Limited (www.yaang.com)

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