Pipes and Tubes

Pipes and Tubes

SS 304 Tube and SS 304 Pipe is made from austenitic stainless steel also known as 18/8 stainless steel because of its chemical composition. SS 304 pipes and tubes due to its austenitic structure are ductile in nature. It also has excellent low temperature properties and responds well to hardening by cold working. If intergranular corrosion in the heat affected zone may occur, it is suggested that SS 304L be used.

Chemical Composition

GRADE

 

NI

CR

Si

C

MN

P

S

N

Fe

SS 304

MIN %

8

18

     

MAX %

13

20

0.75

0.08

2

0.045

0.03

0.1

BALANCE

SS 304H

MIN %

8

18

     

MAX %

12

20

0.75

0.03

2

0.045

0.03

0.1

BALANCE

SS 304L

MIN %

8

18

0.04

     

 

MAX %

10.5

20

0.75

0.1

2

0.045

0.03

 

BALANCE

Specification

Stainless steel 304/H/L Seamless Pipe : ASTM/ASME SA 312/ A 312

Stainless steel 304/H/L Seamless tube : ASTM/ASME SA 213/A 213

Stainless steel 304/H/L ERW Pipe          : ASTM/ASME SA 312/ A 312

Stainless steel 304/H/L ERW Tube          :ASTM/ASME SA 249/ A 249

General Specifications

GRADE

UNS

OLD BRITISH

EURONORM

SWEDISH SS

JAPANESE JJ

   

BS

EN

NO

NAME

   

SS 304

S30400

304S31

58E

1.4301

X5CrNi 18-10

2332

SUS 304

SS 304L

S30403

304S11

1.4306

X2CrNi 19-10

2352

SUS 304L

SS 304H

S30409

304S51

1.4948

X6CrNi 18-10

Production Process

Stainless steel 304 Tube and Stainless steel 304 Pipe or UNS 304000 are manufactured by 304 stainless steel pipe supplier such as ERW ( Electric Resistance Welded), Seamless and EFW ( Electric Fusion Welding) Pipes and Tubes having different form such as round, square, rectangle, etc. having specific end as Plain End, Bevel End and Threaded End with nominal thickness of different schedule ranging from SCH 5 to SCH XXS. 

The process through which  stainless steel pipe SS 304 and tubes can be manufactured include cold pilgering process, Extrusion process, tube mill Process also Piercing process followed by heat treatment and mechanical testing.

Fabrication and Heat treatment

According to the 304 stainless steel pipe specifications, this grade readily hardens. In SS 304 pipes and tubes fabrication methods involving cold working may require an intermediate annealing stage to alleviate work hardening and avoid tearing or cracking. 

Fabrication methods, like forging, that involve hot working should occur after uniform heating to 1149-1260°C. The fabricated components should then be rapidly cooled to ensure maximum corrosion resistance.

Stainless steel 304 cannot be hardened by heat treatment.  At the completion of fabrication a full annealing operation should be employed to reduce internal stresses and optimise corrosion resistance. Solution treatment or annealing is done by rapid cooling after heating to 1010-1120°C.

Properties

Stainless steel 304 has good resistance to oxidation in intermittent service up to 870°C and in continuous service to 925°C. However, continuous use at 425-860°C is not recommended if corrosion resistance in water is required. In this instance 304L is recommended due to its resistance to carbide precipitation.

Mechanical Properties

Grade

Tensile Strength

Yield Strength

Elongation

Hardness, MAX

[MPA]

[MPA]

(% in 50mm) min

HBW

HRB

SS 304

515

205

40

95

217

SS 304H

260

90

40

95

217

SS 304L

485

170

35

95

Where high strength is required at temperatures above 500°C and up to 800°C, grade 304H is recommended. This material will retain aqueous corrosion resistance.

SS 304 Tube and SS 304 Pipe has a higher corrosion  resistance than regular steel and is widely used because of the ease in which it is formed into various shapes.

Physical Properties

Grade

Density (g/cm3)

Elastic Modulus (GPa)

Mean Co-eff of Thermal Expansion (μm/m/°C)

Thermal Conductivity (W/m.K)

Specific Heat 0-100°C (J/Kg.K)

Electrical Resistivity (nΩ.m)

0-100°C

0-315°C

0-538°C

at 100°C

at 500°C

SS 304/H/L

8

193

17.2

17.8

18.4

16.2

21.5

500

720

Application

  • Food processing equipment, particularly in beer brewing, milk processing & winemaking
  • Kitchen benches, sinks, troughs, equipment and appliances
  • Architectural paneling, railings & trim
  • Chemical containers, including for transport
  • Heat Exchangers
  • Woven or welded screens for mining, quarrying & water filtration
  • Threaded fasteners
  • Springs