Stainless Steel: 317 (UNS S31700)

Since its invention, Stainless Steel has gained huge popularity because of its highly useful properties including corrosion resistance, high strength and durability. Based on the chemical composition of stainless steel, it is available in different grades. Characterized by different properties these grades are used for varied applications. One of the common grades of stainless steel is grade 317 also known as UNS S31700.

About Grade 317 Stainless Steel

Grade 317 is a modified version of grade 316. 317 Stainless Steel is highly resistant to corrosion even in extreme environments. It also provides good mechanical properties at high temperatures. Furthermore, it can be easily fabricated and welded.  This grade is particularly known for its resistance to corrosion in acidic environments. It is widely used for chemical and petrochemical processing, marine applications, and food processing. It is also used in medical implants and surgical instruments.

AISI 317 Chemical Composition

The main differentiation factor between the various grades of stainless steel is its chemical properties. Even a small variation in the chemical composition of these stainless steel grades can lead to major differentiation in their properties. 

Let us have a quick look at the chemical composition of AISI 317:

 

Iron, Fe

61%

Chromium, Cr

19%

Nickel, Ni

13%

Molybdenum, Mo

3.50%

Manganese, Mn

2%

Silicon, Si

1%

Carbon, C

0.080%

Phosphorous, P

0.045%

Sulfur, S

0.030%

 

Physical Properties

The knowledge of the physical properties of grade 317 can help you make an informed decision while selecting it for various applications ensuring optimal performance. Below are the physical properties of grade 317.

Density 8 g/cm3

Melting point 1370°C

Mechanical Properties

The mechanical properties of grade 317 are the determining factors of its uses in various applications. Here are the various mechanical properties of grade 317:

 

Tensile strength

620 MPa

  

Yield strength

275 MPa

  

Elastic modulus

193 GPa

  

Poisson's ratio

0.27-0.30

  

Elongation at break (in 50 mm)

45%

  

Hardness, Rockwell B

85

  

 

Thermal Properties

The thermal properties of various grades of stainless steel vary based on their chemical composition. Below are the thermal properties of grade 317.

Thermal expansion coefficient (@ 0-100°C/32-212°F)

16 µm/m°C

  

Thermal conductivity (@ 100°C/212°F)

16.3 W/mK

  

Applications

Grade 317 is an austenitic chromium-nickel-molybdenum grade of stainless steel with high corrosion resistance and formability. This thus easily fits into usages directly or indirectly related to various industries including: 

  • Chemical and petrochemical industry
  • Fertilizer, and power generation; 
  • Food processing,
  • Water supply systems
  • Medical instruments.