Stainless Steel Plate Sheet 347

Sandmeyer Steel Company stocks Alloy 347 stainless steel plate in thicknesses from 3/16" through 4". A high carbon version, Alloy 347H (UNS S34709) stainless steel plate, can also be ordered in the same thickness range.

Available thicknesses for Alloy 347:

3/16" 1/4" 5/16" 3/8" 1/2" 5/8" 3/4" 7/8" 1" 1 1/8"
4.8mm 6.3mm 7.9mm 9.5mm 12.7mm 15.9mm 19mm 22.2mm 25.4mm 28.6mm
1 1/4" 1 1/2" 1 3/4" 2" 2 1/4" 2 1/2" 2 3/4" 3" 3 1/2" 4"
31.8mm 38.1mm 44.5mm 50.8mm 57.2mm 63.5mm 69.9mm 76.2mm 88.9mm 101.6mm
Alloy 347 (S34700) is stabilized stainless steel plate which offers as its main advantage an excellent resistance to intergranular corrosion following exposure to temperatures in the chromium carbide precipitation range from 800 to 1500°F (427 to 816°C). Alloy 347 stainless steel plate is stabilized by the addition of columbium and tantalum.

Alloy 347 stainless steel plate is also advantageous for high temperature service because of its good mechanical properties. Alloy 347 stainless steel plate offers higher creep and stress rupture properties than Alloy 304 and, particularly, Alloy 304L, which might also be considered for exposures where sensitization and intergranular corrosion are concerns.

General Properties


Alloy 347 (UNS S34700) is columbium stabilized austenitic stainless steel plate with good general corrosion resistance and somewhat better resistance in strong oxidizing conditions than 321 (UNS S32100). It has excellent resistance to intergranular corrosion after exposure to temperatures in the chromium carbide precipitation range of 800 – 1500°F (427 – 816°C). The alloy has good oxidation resistance and creep strength to 1500°F (816°C). It also possesses good low temperature toughness.

Alloy 347H (UNS S3409) stainless steel plate is the higher carbon (0.04 – 0.10) version of the alloy. It was developed for enhanced creep resistance and for higher strength at temperatures above 1000°F (537°C). In most instances, the carbon content of the plate enables dual certification.

Alloy 347 stainless steel plate cannot be hardened by heat treatment, only by cold working. It can be easily welded and processed by standard shop fabrication practices.

Applications

  • Chemical Processing
  • Food Processing – equipment and storage
  • Petroleum Refining – fluid catalytic cracking units, polythionic acid service
  • Pharmaceutical Production
  • Waste Heat Recovery – recuperators

Standards

ASTM........A 240
ASME........SA 240
AMS..........5512

Corrosion Resistance

Alloy 347 stainless steel plate exhibits good general corrosion resistance that is comparable to 304. It was developed for use in the chromium carbide precipitation range of 800 – 1500°F (427 – 816°C) where un-stabilized alloys such as 304 are subject to intergranular attack. In this temperature range, the overall corrosion resistance of Alloy 347 stainless steel plate is superior to Alloy 321 stainless steel plate. Alloy 347 also performs somewhat better than Alloy 321 in strongly oxidizing environments up to 1500°F (816°C).

The alloy can be used in nitric solutions, most diluted organic acids at moderate temperatures and in pure phosphoric acid at lower temperatures and up to 10% diluted solutions at elevated temperatures. Alloy 347 stainless steel plate resists polythionic acid stress corrosion cracking in hydrocarbon service. It can also be utilized in chloride or fluoride free caustic solutions at moderate temperatures.

Alloy 347 stainless steel plate does not perform well in chloride solutions, even in small concentrations, or in sulfuric acid.

Chemical Analysis

Weight % (all values are maximum unless a range is otherwise indicated)
Element 347 347H
Chromium 17.00 min.-19.00 max. 17.00 min.-19.00 max.
Nickel 9.00 min.-13.00 max. 9.00 min.-13.00 max.
Carbon 0.08 0.04 min.-0.10 max.
Manganese 2.00 2.00
Phosphorus 0.045 0.045
Sulfur 0.03 0.03
Silicon 0.75 0.75
Columbium & Tantalum 10 x (C + N) min.-1.00 max. 8 x (C + N) min.-1.00 max.
Iron Balance Balance

Physical Properties

Density

0.288 lbs/in3
7.96 g/cm3

Specific Heat

0.12 BTU/lb-°F (32 – 212°F)
500 J/kg-°K (0 – 100°C)

Modulus of Elasticity

28.0 x 106 psi
193 GPa

Thermal Conductivity 200°F (100°C)

133 BTU/hr/ft2/ft/°F
16.3 W/m-°K

Melting Range

2550 – 2635°F
1398 – 1446°C

Electrical Resistivity

72 Microhm-cm at 20°F

Mechanical Properties

Typical Values at 68°F (20°C)

Yield Strength
0.2% Offset
Ultimate Tensile
Strength
Elongation
in 2 in.
Hardness
psi (min.) (MPa) psi (min.) (MPa) % (min.) (max.)
30,000 205 75,000 515 40 201 Brinell

Fabrication Data

Alloy 347 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.

Machining

The cold work hardening rate of 347 stainless steel plate makes it less machinable than 410 stainless steel, but similar to 304. The table below provides relevant machining data.

Operation Tool Lubrication CONDITIONS
      Depth-mm Depth-in Feed-mm/t Feed-in/t Speed-m/min Speed-ft/min
Turning High Speed Steel Cutting Oil 6 .23 0.5 .019 12-16 39-52
Turning High Speed Steel Cutting Oil 3 .11 0.4 .016 18-23 59-75
Turning High Speed Steel Cutting Oil 1 .04 0.2 .008 23-28 75-92
Turning Carbide Dry or Cutting Oil 6 .23 0.5 .019 67-76 220-249
Turning Carbide Dry or Cutting Oil 3 .11 0.4 .016 81-90 266-295
Turning Carbide Dry or Cutting Oil 1 .04 0.2 .008 99-108 325-354
      Depth of cut-mm Depth of cut-in Feed-mm/t Feed-in/t Speed-m/min Speed-ft/min
Cutting High Speed Steel Cutting Oil 1.5 .06 0.03-0.05 .0012-.0020 16-21 52-69
Cutting High Speed Steel Cutting Oil 3 .11 0.04-0.06 .0016-.0024 17-22 56-72
Cutting High Speed Steel Cutting Oil 6 .23 0.05-0.07 .0020-.0027 18-23 59-75
      Drill ø mm Drill ø in Feed-mm/t Feed-in/t Speed-m/min Speed-ft/min
Drilling High Speed Steel Cutting Oil 1.5 .06 0.02-0.03 .0007-.0012 9-13 29-42
Drilling High Speed Steel Cutting Oil 3 .11 0.05-0.06 .0020-.0024 11-15 36-49
Drilling High Speed Steel Cutting Oil 6 .23 0.08-0.09 .0031-.0035 11-15 36-49
Drilling High Speed Steel Cutting Oil 12 .48 0.09-0.10 .0035-.0039 11-15 36-49
          Feed-mm/t Feed-in/t Speed-m/min Speed-ft/min
Milling Profiling High Speed Steel Cutting Oil     0.05-0.10 .002-.004 11-21 36-69

Welding

Alloy 347 stainless steel plate can be readily welded by most standard processes. A post weld heat treatment is not necessary.

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