CF8M Properties, Welding Guidelines


What is CF8M stainless steel?

CF8M is a chromium-nickel-molybdenum alloy with high resistance to oxidation and pitting corrosion. It has excellent resistance to chlorides and other chemical environments.

CF8M material is a non-hardenable alloy as it is an austenitic grade that can not be hardened by heat treatment. CF8M is usually used for service temperature up to 1500 Degree Fahrenheit.

CF8M has good strength and toughness at elevated temperatures. This alloy is used in applications such as values, fittings, process piping flanges, and structural members in the chemical industry.

CF8M Material Specification

CF8M is a versatile austenitic stainless steel that offers good corrosion resistance and strength. It has excellent weldability and formability, making it a popular choice for many applications.

UNS Number of Cf8M Material is J92900. The CF8M material specification covers the chemical and mechanical requirements for this grade of stainless steel.

The main material specifications for CF8M Materials are:

  • ASTM A351
  • ASTM A451
  • ASTM A743
  • ASTM A744
  • 1.4408
  • EN 10283

CF8M Chemical Composition

CF8M is a material composed of chromium, nickel and molybdenum. It offers excellent resistance to both corrosion and heat. It was specifically designed to provide superior corrosion resistance in harsh environments.

The main chemical composition of CF8M material are listed in below Table:

ElementWeight %
Carbon (C)0.08 Max.
Manganese (Mn)1.50 Max.
Silicon (Si)1.50 Max.
Sulfur (S)0.040 Max.
Phosphorus (P)0.040 Max.
Chromium (Cr)18- 21
Nickel (Ni)9.0 -12
Molybdenum (Mo)2.0 -3.0
Chemical Composition of CF8M Casting Material

CF8M Mechanical Properties

CF8M mechanical properties are important to consider when selecting a material for use in corrosive environments. CF8M Tensile Strength is 70 Ksi Minimum, Yield Strength is 30 Ksi & 30% elongation.

The Mechanical Properties of CF8M material are given in the below table:

Tensile Strength70 Ksi (485 MPa) minimum
Yield Strength30 Ksi (205 MPa) minimum
Elongation30% minimum
Hardness 146-212 HB
CF8M Mechanical Properties

CF8M equivalent material

The equivalent material of CF8M is SS316 material and not SS316L which has low carbon content. Comparison of chemical composition of Cf8M and SS316 are given in the below table.

ElementCF8MSS316
Carbon (C)0.08 Max.0.08 Max.
Manganese (Mn)1.50 Max.2.00 Max.
Silicon (Si)1.50 Max.0.75 Max.
Sulfur (S)0.040 Max.0.030 Max.
Phosphorus (P)0.040 Max.0.045 Max.
Chromium (Cr)18- 2116- 18
Nickel (Ni)9.0 -1210- 14
Molybdenum (Mo)2.0 -3.02.0 -3.0
CF8M vs. SS316

CF8M Welding

CF8M material is a non-hardenable alloy as it is an austenitic grade that can not be hardened by heat treatment. CF8M is usually used for service temperature up to 1500 Degree Fahrenheit.

CF8M welding-repair-procedure

CF8M material can be welded using stick welding, TIG Welding or MIG Welding. It is having good weldability and can be easily welded with other stainless steel grades or carbon steel if required.

Welding shall be carried out using stringer beads and low heat input. A high heat input can create issue of sensitization in the material which can impact its corrosion resistance properties.

Stick Welding of CF8M Material

Stick welding of CF8M can be carried out using E316-15/ E316-16 type stick welding electrode. E316-15 or E316-16 or E316-17, any of these welding rod can be used for welding applications. CF8M to SS304 can also be welded using the same E316L type welding electrode.

TIG/ MIG Welding of CF8M Material

TIG Welding or MIG Welding of CF8M material is carried out using ER316 welding filler wire. Pure argon gas is used for welding shielding applications. No preheat is required for welding of CF8M material.

For open root in Groove welds, back purging using pure argon or helium is required when welding CF8M material. No back purging is required for Fillet weld or T-Joints.

Is CF8M the same as 316L?

No, CF8M and SS316L are not the same material. The equivalent grade of SS316L is CF3M. A Comparison of CF8M and SS316 Chemical properties are given in the below table for reference.

ElementCF8MSS316
Carbon (C)0.08 Max.0.08 Max.
Manganese (Mn)1.50 Max.2.00 Max.
Silicon (Si)1.50 Max.0.75 Max.
Sulfur (S)0.040 Max.0.030 Max.
Phosphorus (P)0.040 Max.0.045 Max.
Chromium (Cr)18- 2116- 18
Nickel (Ni)9.0 -1210- 14
Molybdenum (Mo)2.0 -3.02.0 -3.0
CF8M vs. SS316

CF8M vs. SS304

Both SS304 and CF8M are type of austenitic stainless steel material although both are not same chemical composition. CF8M is having higher added molybdenum that gives higher pitting corrosion resistance compared to SS304 materials.

Also, CF8M is having high strength and higher overall corrosion resistance properties compared with SS304 grade.

Cost wise, SS304 is cheaper than CF8M alloy.

CF8 vs. CF8M

Both CF8 and CF8M are austenitic stainless steel alloys having almost similar chemical composition and mechanical properties. Although, CF8M has higher corrosion resistance compared to CF8.

Below tables highlights the main differences between CF8 and CF8M material chemical compositions.

ElementCF8MCF8
Carbon (C)0.08 Max.0.08 Max.
Manganese (Mn)1.50 Max.1.50 Max.
Silicon (Si)1.50 Max.2.00 Max.
Sulfur (S)0.040 Max.0.030 Max.
Phosphorus (P)0.040 Max.0.045 Max.
Chromium (Cr)18- 2118- 21
Nickel (Ni)9.0 -128- 11
Molybdenum (Mo)2.0 -3.00.50 Max.
CF8M vs. CF8 alloy

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