How to Choose the Right Inconel Round Bar for Your Project

Material failure is not a possibility in high-performance industries, such as aerospace, oil and gas, and chemical processing. Even one component failure may lead to disastrous effects, multi-million dollar downtime and even safety risks. In extreme conditions, such as high temperature, hostile corrosion, or tough mechanical loads, regular steel is not going to be good enough.

It is at this point that Inconel Round Bars come into play. These are supernickel-based high-performance alloys which are designed to handle the conditions that would ruin other conventional materials. Nevertheless, making a decision based on a wrong grade may be as hazardous as making a decision based on a substandard material.

The problem is the knowledge of the three major ones: Inconel 718, Inconel 625, and Incoloy 925. All grades are excellent in particular uses, although the misuse of the wrong grade may cause early cracking, disastrous corrosion, or structural collapse.

At USA Piping Solution, we maintain a full-fledged inventory of Nickel Alloy Inconel Round Bars and collaborate with engineers in different regions of the world to make sure that they pick the best grade of the same to be used in their critical applications. This guide will allow you to make the right choice depending on the requirements on your project

Extreme Strength & Heat (Choose Inconel 718)

Inconel 718 Round Bars are the best when your project needs retention at high temperatures. This grade is the most popular type of the world precipitation-hardening nickel alloy, and with reason.

Key Properties and Applications

High performance of Inconel 718 comes along due the precipitation hardening, which is a metallurgical process that builds microscopic-sized precipitates of the alloy. These precipitates are barriers to dislocation mobilities, which remarkably increase the strength and the high temperature deformation resistance of the material.

The alloy has a retention of its mechanical properties up to 1300°F (700 °C), hence ideal in:

•  Turbine blades, disks, and shafts (jet engine parts).
•  Gas turbine equipment (baskets, cases, ducts)
•  High pressure valves and fasteners.
•  Components of steam turbine Nuclear reactor internals.

Technical Specifications

Inconel 718 is produced based on the ASTM B637 standards that outline the chemical traits and mechanical characteristics that need to be met in case of the application in aerospace and industry. The alloy will normally have:

•  Tensile Strength: 180-220 ksi (1240-1517 MPa)
•  Yield Strength: 150-180 ksi (1034-1241 MPa)
•  Operating Temperature: 700C to 1300F (380 o C to 1300 F ).
•  High fatigue efficiency even in cyclic loading.

Innel rod form especially finds application in machining complicated parts where tolerance of dimensions is very important. To use high yield strength at high temperatures, browse our inventory of Inconel 718 Round Bars.

Maximum Corrosion Resistance (Choose Inconel 625)

Inconel 625 round bar is a better choice when maximum strength is not important, but corrosion resistance is required. This grade has a high level of resistance to a wider variety of corrosive conditions than nearly any other nickel alloy.

Key Properties and Applications

Inconel 625 has a very high percentage of molybdenum content (8-10%), which is combined with a significant amount of chromium and nickel, which is the secret of its amazing corrosion resistance. This mixture gives excellent resistance to:

Pitting and crevice corrosion in chloride corrosion, Stress corrosion cracking in high-temperature water, Oxidation up to 1800 °C (980 °C)

• The elimination of acids such as hydrochloric and sulfuric acid has primary uses:
• Heat exchangers, reaction vessels Chemical processing equipment.
• Maritime engineering (piping of seawater, offshore platforms)
• Pollution prevention systems ( desulfurization of flue gas).
• Tubing Nuclear steam generator Tubing Aerospace exhaust systems.

Technical Specifications

Inconel 625 to the ASTM B446 standards, provides: 

•  Tensile Strength: 120-160 ksi (827-1103 MPa)
•  Yield Strength: 60-110 ksi (414-758 MPa)
•  Operating Temperature: To 1800 °F (980 °C) in oxidizing conditions.
• Outstanding weldability without heat treatment of the post-weld.
  
  

Inconel 625 can be produced more easily and fabricated as it is more ductile compared to precipitation-hardened alloys because its strength is solid-solution strengthened.

Inconel 625 round bar is recommended to use if the project concerns seawater or acids are harsh.

Sour Gas & Downhole Drilling (Choose Inconel/Incoloy 925)

Incoloy 925 round bar (technically Inconel 925) is the best strength to corrosion trade-off balance in oil and gas appliances of sour gas service and downhole applications.

Important Nomenclature Clarification -Although most of the engineers seek Inconel 925 round bar, it is noteworthy that the material is officially referred to as Incoloy 925 (UNS N09925). Inconel and Incoloy are the same manufacturer ( Special Metals Corporation ), except that Incoloy usually denotes iron-nickel-chromium alloys, whereas Inconel denotes nickel-chromium alloys. The terms, however, are interchangeable within the industry to refer to this particular grade.

Key Properties and Applications

Incoloy 925 is a mixture of high-strength Inconel 718 with increased corrosion resistance like Incoloy 825. This special combination renders it the best suited to the most demanding oil and gas uses:

•  The compliance of sour gas service under NACE MR0175.
• Wellhead equipment and packers, hangers, Downhole drilling equipment, and tools.
• High-pressure high temperature (HPHT) applications.

Technical Specifications

Incoloy 925 comes under ASTM B805 specification, and provides:

•  Tensile Strength: 130-170 ksi (896-1172 MPa)
•  Yield Strength: 95-130 ksi (655-896 MPa)
•  Superior resistance to a hydrogen sulfide (H 2 S) environment.
•  Excellent stress corrosion cracking strength in chloride-containing fluids.

The precipitation hardening capability of the alloy enables it to retain its strength at up to 1200 o C (650 C) temperature and in the sour gas corrosion.

For sour gas applications, we recommend our specializedIncoloy 925 round bars.

Quick Comparison Table: 718 vs. 625 vs. 925

Manufacturing Factors: Surface Finish and Tolerance

Using Inconel bar stock, both performance and cost are impacted heavily when specifying the Inconel bar stock. These factors would be understood to ensure you do get the material that has been optimized to meet your application.

Bar Stock Forms

Inconel alloy round rods are furnished in three major conditions:

• Hot Rolled (Black Bar): The most economical variant that has a mill scale surface. Applicable to where the finish at the surface is not essential or where the surface layer is going to be removed by considerable machining.
• Cold Drawn (Bright Bar): Excellent surface and dimensional finish. The cold drawing process hardens the surface, and this may enhance the strength but may also decrease ductility.
• Peeled/Polished: Finished surface that is of high quality through machining or grinding. Necessary in situations where fatigue loading is required, or where cracking may be triggered at surface defects.
• Precision and Tolerances: When machining complex components, precision grinding of Inconel bar stock becomes a serious issue. Inconel alloys have a notorious hard-to-machine nature because of the nature of work-hardening and low thermal conductivity. A final diameter and high-quality finish lead to a decrease in machining time and tool wear.

We supply various finishes of Inconel pipes and rodsto meet your specific manufacturing requirements.

Ready to discuss your project needs? Contact us today for a quick quote!

Conclusion

The choice of the appropriate Inconel Round Bars for your project is reduced to knowing what it is you need the most:

• Use Inconel 718 where high temperature strength at high temperatures is most important (aerospace, gas turbines)
• Select Inconel 625 where the need is corrosion resistance in harsh conditions (chemical processing, marine).
• Use Incoloy 925 where both strength and sour gas resistance are needed (oil and gas, downhole use)

The impact of making a wrong grade can be disastrous - jet engines can crash, oil wells might blow up. Do not make a bet with material failure due to the lack of full information.

At USA Piping Solution, it is not just material we are selling you, this is our metallurgical know-how to make your project successful. Our technical department knows the peculiarities of every grade and may assist you in the difficult decision-making process.

Need Expert Material Selection Guidance?

Talk to our accredited metallurgists to make sure that you choose the ideal Inconel grade to use in your critical application.

Request a Quote for Inconel Rods Today!