| 3/16" | 1/4" | 5/16" | 3/8" | 1/2" | 5/8" |
|---|---|---|---|---|---|
| 4.8mm | 6.3mm | 7.9mm | 9.5mm | 12.7mm | 15.9mm |
| 3/4" | 7/8" | 1" | 1 1/8" | 1 1/4" | 1 1/2" |
| 19mm | 22.2mm | 25.4mm | 28.6mm | 31.8mm | 38.1mm |
| 1 3/4" | 2" | 2 1/4" | 2 1/2" | 2 3/4" | 3" |
| 44.5mm | 50.8mm | 57.2mm | 63.5mm | 69.9mm | 76.2mm |
| 3 1/2" | 4" | ||||
| 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.
