Type 347 stainless steel has slightly improved corrosion resistance over type 321 stainless steel in strongly oxidizing environments. Type 347 is stabilized with columbium, it is preferable for aqueous and low temperature environments due to its good resistance to intergranular attack. Both 347 and 321 offer good resistance to polythionic acid stress corrosion cracking, encountered in oil refineries. The high temperature oxidation resistance of 347 is similar to that of 304 stainless steel. Useful to 1500°F.

Stainless Steel Tube Standards:

American standards:

ASTM A249: Standard specification for welded austenitic steel boiler,superheater, heat-exchanger and condenser tubes.

ASTM A269:Standard specification for welded austenitic stainless steel tubing for general service.

ASTM A688:Standard specification for welded austenitic stainless steel feedwater heater tubes.

ASTM A554:Standard specification for welded stainless steel mechanical tubing.

ASTM A268:Specification for seamless and welded Ferritic/Martensitic stainless steel tubing for General Service

ASTM A789:Specification for seamless and welded Ferritic/Austenitic stainless steel tubing for General Service

ASTM A312:Seamless/Welded austenitic stainless steel pipe

Germanic standards:

DIN17455:General purpose welded circular stainless steel tubes

DIN17457: Welded circular austenitic stainless steel tubes subject to special requirements; technical delivery conditions

European Standard:

EN 10217-7:Welded Steel Tubes for pressure purposes-Part 7 Stainless steel tubes

U-Bent Tubes

SPEZILLA Tube heat exchanger tubes can also be supplied as 'u' bends or serpentines, manufactured according to various heat exchanger standard or to customer's own specifications.

Standard Technical Range

OD 9.5mm - 38.1mm
WT up to 6.35mm
Bending radii 1.25 x OD up to 1700mm
Bends can be supplied in accordance with TEMA R / ASTM SA/A556
Leg length up to 15000mm
Heat treatment where required by electric furnance or direct resistance
Hydrotesting up to 10,000 psi

Additional Testing

Dye penetrant of 'U' bend area
PMI testing
Heat Treatment

Heat Treatment

We are equipped to carry out heat treatment of bends plus a minimum 150mm of leg.

Heat Treatment Equipment

Heat treatment equipment is computer controlled with the added facility of data recording.
An argon protective atmopshere is used inside stainless and special alloy tubes during heat treatment.
We can provide all types of annealing; solution annealing and stress relieving.

SA-213-TP347H

Seamless ferritic and austenitic alloy steel boiler, superheater, and heat exchanger tubes

Chemical Properties:

Carbon: 0.04-0.10	Silicon: 0.75 max
Manganese: 2.00	Nickel: 9.00-13.0
Potassium: 0.04	Chromium: 17.0-20.0
Sulfur: 0.03	Molybdenum: n/a

Mechanical Properties:
Tensile Strength:
ksi: 75
MPa: 517
Yield:
ksi: 30
MPa: 207
Elongation in 2in. or 50mm, min. %: 35
Max. Hardness Rockwell B: 90

Standard Dimensions - U-Bent Tube
Outside diameter	6 ÷90 mm	¼”÷3 ½”
Maximum overall length	1 ÷ 28 m	3 ÷ 92 ft
Bending Radius Min.	1,5 × tube diameter
Bending Radius Max.	1500 mm	4ft

Inspections and Tests - U-Bent Tube
Chemical Composition
Mechanical Properties
Hydrostatic Test
Pneumatic Test
Eddy Current Test
Dye Penetrant Test
Magnetoscopic Test

Heat Treatment Conditions
Stress-Relieved Anneal
Annealed (Bright Annealing)

Materials - U-Bent Tube
Carbon Steel	SA 179 / A 179
Carbon Steel	SA 210 / A 210
Carbon Steel	SA 334 / A 334
Stainless Steel	SA 213 / A 213
	SA249 / A249
	SA268 / A268
	SA688 / A688
Duplex Stainless Steel	SA 789 / A 789
Copper & Cu Alloys	SB 111 / B 111
Titanium & Ti Alloys	SB 338 / B 338
For different materials please contact our sales department.

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